NZ739541B2 - Processing Biomass For Use In Fuel Cells - Google Patents

Abstract

The disclosure relates to a method of processing biomass by the saccharification of a lignocellulosic or cellulosic material (e.g., by contacting the material with an enzyme) to produce a carbohydrate solution that can be used in a fuel cell, e.g., a direct glucose fuel cell, an indirect sugar fuel cell and a biological fuel cell. Particularly disclosed is a method comprising: enzymatically saccharifying a cellulosic or lignocellulosic material to form a sugar solution with a sugar concentration greater than 40% by weight, wherein the solution comprises xylose and glucose; delivering the sugar solution to a microbial fuel cell containing an anti-scale agent or an anti-fouling agent; and utilizing, the sugar solution at a pH of between 6 and 10 in the microbial fuel cell. cell and a biological fuel cell. Particularly disclosed is a method comprising: enzymatically saccharifying a cellulosic or lignocellulosic material to form a sugar solution with a sugar concentration greater than 40% by weight, wherein the solution comprises xylose and glucose; delivering the sugar solution to a microbial fuel cell containing an anti-scale agent or an anti-fouling agent; and utilizing, the sugar solution at a pH of between 6 and 10 in the microbial fuel cell.

Description

PROCESSING BIOMASS FOR USE IN FUEL CELLS RELATED APPLICATIONS This application claims priority to U.S. Provisional Application Serial No. 61/579,568, filed er 22, 2011, the complete disclosure therein incorporated herein by reference.

BACKGROUND Cellulosic and lignocellulosic materials (e.g., biomass materials) are produced, processed, and used in large quantities in a number of applications. Often such materials are used once, and then discarded as waste, or are simply considered to be waste materials, e.g., sewage, bagasse, sawdust, and stover.

A typical biomass material contains cellulose, hemicellulose, and lignin plus lesser amounts of proteins, extractables and minerals. The complex carbohydrates contained in the cellulose and hemicellulose fractions can be processed into fermentable sugars by saccharification, using a cellulolytic , and the sugars can then be used as an end product or intermediate, or converted by further bioprocessing, e.g., fermentation, into a variety of products, such as ls or organic acids. The product obtained depends upon the microorganism utilized and the conditions under which the bioprocessing occurs.

SUMMARY This ion relates to methods of processing (e.g., saccharifying) ydrate-containing materials (e.g., biomass materials or biomass-derived materials) to produce sugar (e.g., glucose) ons that can be used in fuel cells such as direct sugar fuel cells, indirect sugar fuel cells and biological fuel cells. The invention also relates to ing the carbohydrate-containing material derived sugars solutions in fuel cells.

The invention also relates to method comprising: enzymatically saccharifying a osic or lignocellulosic material to form a sugar solution with a sugar concentration r than 40% by weight, n the solution comprises xylose and e; delivering the sugar solution to a microbial fuel cell containing an anti-scale agent or an anti-fouling agent; and ing, the sugar solution at a pH of between 6 and 10 in the ial fuel cell.

In some implementations, the sugar solution is produced by the saccharification of a lignocellulosic or cellulosic material, for example by contacting the material with an enzyme (e.g., a cellulase). In other implementations the recalcitrance of the lignocellulosic or cellulosic material has been reduced relative to [Text continued on page 2] that of the material in its native state prior to saccharification. In some cases, ng the itrance of the feedstock includes treating the feedstock with a treatment.

The treatment can be, for example, ionization ion (e.g., electron beam radiation), sonication, pyrolysis, oxidation, steam explosion, chemical treatment, various mechanical treatments and combinations of any of these treatments. The al treatment can comprise any one or more of the treatments disclosed , applied alone or in any desired combination, and applied once or multiple times. When treating with ionizing radiation, e.g., electron beam radiation, the dosage can be at least 10 Mrad and less than about 200 Mrad (eg., 50 Mrad to lSOMrad).

In some entations, the method can include using an additive in the fuel cell. For example additives can be acids, bases, buffers (e.g., phosphate buffers), minerals, colloids, emulsions, emulsifiers, particulates, nano-particles, cations, anions, metal ions (e.g., Fe2+’ Fe3+, Mn2+, Cu2+, K+, Na+), vitamins, enzymes, peptones, extracts, surfactants, nutrients, gases (e.g., hydrogen, nitrogen, , argon, carbon monoxide, carbon dioxide) sources (e.g., ammonia, urea), , chemicals, en pigments, fragrances, anionic polymers, cationic polymers, non-ionic polymers, oligomers, lipids, fats, surfactants, dispersants, anti-foam agents, bacteriostatic agents, antimicrobial agents, rganisms, viscosity modifiers, oxidizing agents (e.g., peroxides, tes), reducing agents, anti-scale agents, corrosion inhibitors, antifouling agents, itating agents, coagulants added in any combination and sequence.

A typical biomass resource contains cellulose, hemicellulose, and lignin plus lesser amounts of proteins, extractables and minerals. In some implementations, cellulosic or lignocellulosic al includes paper, paper ts, paper waste, paper pulp, pigmented papers, loaded papers, coated papers, filled papers, magazines, printed matter, printer paper, polycoated paper, card stock, cardboard, paperboard, offal, cotton, wood, particle board, forestry wastes, sawdust, aspen wood, wood chips, s, switchgrass, miscanthus, cord grass, reed canary grass, grain residues, rice hulls, oat hulls, wheat chaff, barley hulls, agricultural waste, silage, canola straw, wheat straw, barley straw, oat straw, rice straw, jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn stover, soybean , corn fiber, alfalfa, hay, coconut hair, sugar processing residues, bagasse, beet pulp, agave bagasse, algae, d, manure, sewage, arracacha, buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum, WO 96452 potato, sweet potato, taro, yams, beans, favas, lentils, peas, and mixtures of any of these.

The cellulosic or lignocellulosic material can be mechanically treated to reduce the bulk density of the cellulosic or ellulosic material and/or increase its surface area. In some implementations, the method es ically treating the feedstock before and/or after reducing its recalcitrance. Mechanical treatments include, for example, cutting, milling, e.g., hammermilling, pressing, grinding, shearing and chopping. For e, comminuting the biomass material can be effective treatment applied to the s material. Mechanical treatment can reduce the bulk density of the feedstock and/or increase the e area of the feedstock. In some embodiments, after mechanical ent the material has a bulk y of less than 0.75 g/cm3, e.g., less than about 0.7, 0.65, 0.60, 0.50, 0.35, 0.25, 0.20, 0.15, 0.10, 0.05, or less, e.g., less than 0.025 g/cm3. Bulk density is determined using ASTM D1 895B.

In one aspect, the invention features utilizing, a sugar solution derived from a cellulosic or lignocellulosic material as described above in a fuel cell, e.g., a direct sugar fuel cell, an indirect sugar fuel cell and/or a biological fuel cell. Optionally the fuel can be a sugar or an alcohol derived from the saccharification of the cellulosic or lignocellulosic material.

Other features and advantages of the ion will be apparent from the following detailed description, and from the claims.

DESCRIPTION OF DRAWINGS is a diagram illustrating the enzymatic hydrolysis of cellulose to glucose. is a flow diagram illustrating conversion of a biomass feedstock for use in a fuel cell. is a diagram showing various processes using saccharified feedstock in fuel cells. is a diagrammatic view of an e of a direct glucose fuel cell. is a diagrammatic view of an example of an indirect sugar fuel cell. is a diagrammatic view of a half-cell of a biological fuel cell.

DETAILED DESCRIPTION ing to during saccharification, a cellulosic or lignocellulosic substrate is initially hydrolyzed by endoglucanases at random locations ing oligomeric intermediates. These intermediates are then substrates for exo-splitting glucanases such as cellobiohydrolase to produce cellobiose from the ends of the cellulose polymer. iose is a water-soluble 1,4-linked dimer of glucose. Finally cellobiase cleaves cellobiose to yield glucose. The glucose, or other sugars, derived from saccharification can be utilized in a fuel cell as will be described in detail herein.

Referring to a s for manufacturing sugar ons for incorporation into a fuel cell system can include, for e, optionally mechanically treating a cellulosic and/or lignocellulosic feedstock (step 110). Before and/or after this treatment, the feedstock can optionally be treated with another physical treatment, for example irradiation, to reduce or further reduce its itrance (step 112). A sugar solution is formed by saccharifying the feedstock (step 114) by, for example, the addition of one or more s (step 111).

Optionally, the method may also include transporting, e. g., by pipeline, railcar, truck or barge, the sugar solution (or the feedstock, enzyme and water, if saccharification is performed en route) to a manufacturing plant (step 116). For example, the methods of transporting and processing biomass as discussed in U.S. Patent 453 filed Jan 21, 2009 can be used herein; the complete disclosure of which is incorporated herein by reference. If desired, the steps of measuring lignin content (step 118) and setting or adjusting process parameters based on this measurement (step 120) can be performed at various stages of the process, for example, as described in U.S. Application Number 12/704,519, filed on February 11, 2011, the complete disclosure ofwhich is incorporated herein by reference. The sugar solution is then incorporated into a fuel cell or fuel cell system (122). Optionally, ts produced in the process can be further processed and/or d, for example, if sugars from the process are ted to products, the product can be d, for example by distillation (124).

The products produced in these processes can also be utilized in a fuel cell system. is a diagram g processes using saccharified feedstock in fuel cells. The sugar solution from the saccharified feedstock can be used in a direct sugar fuel cell, an ct sugar fuel cell or a biological fuel cell. Glucose and xylose are often the most abundant sugars available from biomass and sugar solutions derived from biomass can include a mixture of xylose and glucose in s . For example, only glucose can be present or only xylose can be present, especially in cases when the sugars have been ed and/or purified. When desired, other ratios can be ed, for example as a percent of total glucose and xylose, the amount of glucose can be between 100% and 90%, 90% and 80%, 80% and 70%, 70% and 60%, 60% and 50%, 50% and 40%, 40% and 30%, 30% and 20%, 20% and 10%, 10% and 0%. Although, the glucose and xylose are often abundant biomass d sugars, often providing more than 10 wt. % of the sugar to biomass (e.g., more than 20 wt.%, more than 30 wt.%, more than 40 wt.%, more than 50 wt.%, more than 60 wt.%, or even more than 70 wt.%) and are useful in these different fuel cells, other sugars and polysaccharides can also be useful. For example, arabinose, mannose, galactose and rhamnose, cellulose, starch, xylan, glucuronoxylan, arabinoxylan, glucomannan and xylogulcan can be used. Mixtures of any of these sugars can be utilized. In addition the sugars described herein can be isomerized (e.g., to fructose) and then used in a fuel cell. These different fuel cells and their use are discussed in more detail below.

Direct sugar fuel cells, for example glucose fuel cells, generally include a e electrode, an anode electrode, and a separator (e.g., an anion-exchange ne (AEM) or a diffusion layer.) The fuel cell may be acidic or alkaline. In the example shown in an AEM is sandwiched between an anode electrode and a cathode electrode, with flow fields being provided between each of the electrodes and the AEM. In some cases, the cell has a two-cylinder construction in which one electrode (e. g., the anode) is in the form of an inner cylinder and the other (e.g., the cathode) is in the form of an outer cylinder.

The active ent of the anode may be, for example, PdNi or Pd—Pt, and the active component of the cathode may be, for e, a combined catalyst of cobalt porphyrin x (CoTPP) and spinel (MnC0204) or other suitable catalyst.

In the embodiment of a direct sugar fuel cell shown in a fuel solution containing glucose and, generally, potassium ide (KOH), is fed into the anode flow channel, e.g., by a peristaltic pump (not shown), while oxygen is fed to the cathode flow field. Glucose is oxidized at the anode and the reduced product flows away through an anode exit channel. The electrons flow from the anode and through a load. Oxygen is reduced at the cathode and exhaust gas is vented from the cathode flow field.

WO 96452 Direct sugar fuel cells may or may not completely oxidize the sugar fuel to carbon dioxide and water while generating electricity. For example, the reaction for the total oxidation of e as shown here may occur.

Anode reaction: C6H1206 +24OH' 9 18H20 + 6C02 + 18e- e reaction: 602 + 12H20 + 24e- 9 24OH' Overall reaction: C6H1206 + 602 9 6C02 + 6H20 AH = -2830 KJ/mol Since the total oxidation of glucose proceeds through many intermediates (e.g., gluconic acid, glucaric acid, gamma-gluconolactone, gamma-glucaro lactone, 2- ketogluconic acid, arabinose, trihydroxyglutaric acid, tartaric acid, hydroxyl malonic acid and oxalic acid) any of these intermediates can also be used in a fuel cell. Any of these intermediates, if produced by some of the processed bed herein, (e.g., saccharification, tation) can be useful in generating electricity in a fuel cell.

Optionally, any sugar products not used in generating electricity in the direct sugar fuel cell can be r processed as shown in for example they can be fermented to an alcohol and the alcohol isolated by distillation. In some cases the fuel cell can use one sugar, for example glucose, and does not use other sugars, for example xylose, and the second sugar can be used in subsequent processes. In some other instances, a process, for example fermentation, only uses one sugar (e.g., glucose) g other sugars which can be then used in a fuel cell. In many cases, only a partial oxidation of glucose occurs in a direct sugar fuel cell. For example, the oxidation of e to gluconic acid occurs quickly ing 2 electrons and releasing at most about 200 KJ/mol of energy (e.g., about 7% of the available energy).

In terms of usable energy, the fuel cells convert at least 1% of the fuel to electric energy (e.g., at least 5%, at least 7%, at least 10%, at least 14%, at least 20%, at least %, at least 30 %, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%). In some cases between about 1% and 90% of the fuel is converted to electric energy (e.g., n about 1% and 70%, between about 1% and 50%, between about 1% and 20 %, between about 1% and 10%, between about 5% and 90%, between about 5% and 70%, between about 5% and 50%, between about 5% and 25%, between about 5% and 10%, between about 10% and 90%, between about % and 70%, between about 10% and 50%, between about 10% and 30%, between about 10% and 20%, between about 20% and 70%).

In addition to sugars and products such as alcohols, the solutions derived from biomass by the processes described herein can include various solids or dissolved compounds and/or materials. For example the solutions can include enzymes (e.g., parts of enzymes, active enzymes, denatured enzymes), amino acids, nts, live cells, dead cells, cellular debris (e.g., lysed cells, yeast extract) salts , acids, bases, (e.g., halides, sulfates, and phosphates, alkai, alkali earth, transition metal , partial hydrolysis products (e.g., ous and hemicellulose fragments), , lignin es, nic solids (e.g., siliceous materials, clays, carbon black, metals), remnants of saccharified biomass and combinations f.

Enzymes that can be present can be the intact or denatured enzymes utilized in the processing, or derived from these enzymes (e. g., proteins and amino acids). These can be dissolved/and or precipitated and suspended solids. For example, the sugar solutions can have up to about 10 wt.% enzymes (e.g., up to 9 wt. %, up to 8 wt. %, up to 5 wt. %, up to 2 wt. %, up to 1 wt. %, between about 0.1 and 5 wt. %, between about 1 wt. % and 5 wt. %, between about 2 wt. % and 5 wt. %, between about 0.1 wt. % and 1 wt. %, between about 0.01wt.% and 1 wt.%, between about 0.001 wt.% and 0.1 wt.%).

During saccharification of a biomass, an l pH can often be in the acidic region and therefore the solutions used, if used directly in a fuel cell system, can have a pH between about 2 and 5 (e.g., between about 4 and 5). The pH can also be adjusted up or down after saccharificaion and or saccharification done at a higher or lower pH . In some embodiments the on used in the fuel cell can therefore have pH values selected from a broad range. For example, the pH can be selected from a range of about 2 to about 10 (e.g., between about 2 and 5, between about 3 and 5, between about 3 and 6, between about 4 and 6, between about 5 and 10, between about 6 and 10 between about 8 and 10).

The sugar ons derived from the processes described herein and used in fuel cells systems can e non-sugar suspended or dissolved solids present at concentrations up to about 50 wt.%, for example between about 1 and 50 wt.%, 2 and 40 wt. %, 3 and 25 wt.%, 5 and 25 wt.%, 40 and 50 wt.%, 30 and 40 wt.%, 10 and 20 wt.%, 1 and 5 wt.%, 10 and 40 wt.%, less than about 50 wt.%, less than about 40 wt.%, less than about 30 wt.%, less than about 20 wt.%, less than about 10 wt.%, less than about 5 wt.%, less than about 1 wt.%, less than about 0.5 wt.%, less than about 0.01 wt.%. These solutions can have high turbidity, for e at least about 5 ometric turbidity units (NTU) (e. g., at least abouth NTU, at least about 50 NTU, at least abouthO NTU, at least about 100 NTU at least about 200 NTU, at least about 300 NTU, at least about 400 NTU and even greater than about 500 NTU).

In some cases the solids are completely or partially removed prior to being use in the fuel cells. For example the solids can be removed by filtration, centrifuging, settling, floatation and combinations of these. In some cases the solids are derived from a previously soluble material that has been precipitated, for example an enzyme that has been denatured. After removing the solids the turbidity of the solutions can be reduced by up to about 500 NTU (e.g., reduced by up to about 100 NTU, reduced by up to about 50 NTU, reduced by up to about 5 NTU).

In addition to being turbid, the sugar solutions produced from the ses described herein can be d due to colored impurities. For example some metal ions and polyphenols and lignin derived products produced or released during the processing of a lignocellulosic biomass can be highly colored. The solutions can be used directly in the fuel cell systems described herein or can be partially or completely decolorized prior to being used. For example the colored ties can be d out of the solution, destroyed (e.g., by chemical decomposition) and/or precipitated out of the solution.

The ionic strength of the biomass d sugar solutions can be high due to the source of the biomass as well as the processing of the biomass as described .

The solutions can be used directly or fully, selectively or partially de-ionized prior to being used in the fuel cell systems described herein.

In some ments the fuel cell can include biomass (e. g., lignocellulosic s, cellulosic biomass, starch) as well as a saccharifying enzyme. For example, sugar can be utilized in a fuel cell system while it is being produced by the action of a saccharifying enzyme on a biomass material.

In yet other embodiments the sugar solutions used in the fuel cells herein described can e an additive. Such additives can modify properties of the solutions such as the pH, viscosity, chemical potential, e tension, thermal properties, color, odor, y, ionic strength, conductivity, sterility and/or nutrient value. For example additives can be acids, bases, buffers (e.g., phosphate buffers), minerals, colloids, emulsions, emulsifiers, particulates, nano-particles, cations, anions, metal ions (e.g., Fe2+’ Fe3+, Mn2+, Cu2+, K+, Na+), vitamins, enzymes, peptones, extracts, surfactants, nutrients, gases (e.g., hydrogen, nitrogen, , argon, carbon de, carbon e), chemicals, nitrogen sources (e.g., ammonia, urea), pigments, fragrances, anionic polymers, cationic polymers, non-ionic polymers, oligomers, lipids, fats, surfactants, dispersants, oam agents, bacteriostatic agents, antimicrobial agents, rganisms, viscosity modifiers, oxidizing agents (e.g., peroxides, chlorates), reducing agents, anti-scale agents, corrosion inhibitors, antifouling agents, precipitating agents, coagulants added in any combination and sequence. Additives can be added in ranges from a few parts per million to l percents. For example 1 to 1000 ppm, 5 to 500 ppm, 5 to 100 ppm, 50 to 100 ppm, 100 to 1000 ppm. 1 to 10 wt.%, 2 to 10 wt.%, 5 to 10 wt.%, 2 to 5 wt.%). In some embodiments including s, anions, metal anions the amounts are between 1 to 1000ppm. In some embodiments where acids, bases or buffers are added, the final pH after addition of the additive can be chosen to be between pH 2 and 10, (e.g., between about 4 and 8, between about 5 and 7, between about 6 and 8, between about 4 and 5, between about 7 and 8, between about 8 and 10 and between about 2 and 4).

Additives can also be metered and added in amounts n about 1 uM to 5 M amounts (e.g., between about 1 mM and l M, between about 5 mM and 100 mM, between about 100 mM and 1 molar, between about 10 mM and 100mM). is a mmatic view of an example of an indirect sugar fuel cell.

Generally, the indirect sugar fuel cell uses a biological process to convert a primary fuel to a secondary fuel and the secondary fuel generates a current using a fuel cell.

The primary fuel (1) is brought into contact with a bio-component (2) where it produces a secondary fuel (3) and waste (4). The secondary fuel is brought into the fuel cell and comes into contact with the anode (5) where it is oxidized, producing a reduced product (8), releasing an electron to an external circuit, and providing a proton. The proton travels in the fuel cell through an ion selective membrane (6) to the cathode (7). Oxygen is supplied to the cathode where it is d by electrons supplied from the al circuit and combines with the proton producing water. In another possible design, the bio-component resides within the fuel cell, so that the production of product and electricity all occur within the fuel cell. In some cases, the ion ive membrane is also not required. In other cases the oxidant may be oxidants other than dioxygen (e.g., hydrogen peroxide, organic peroxides and nic peroxides).

The primary fuel used in the indirect fuel cell can be sugars (e.g., glucose and ) as well as polysaccharides that can be ed through the saccharification ofbiomass as previously discussed. The secondary fuel can be a fermentation product ofthe primary fuel. For example, the secondary fuel can be an alcohol or other fermentation t (e.g., ethanol, ol, butanol, polyols, acetic acid, lactic acid and H2 ). Generally, the primary and secondary fuels can be selected from the intermediates and products discussed below. The bio-component can be a microbial material including but are not limited to, any naturally occurring or cally modified microorganism or organism, for example, protists, e.g., animal protists (e.g., protozoa such as flagellates, amoeboids, ciliates, and sporozoa) and plant protists (e.g., algae such alveolates, chlorarachniophytes, cryptomonads, ids, glaucophytes, hytes, red algae, stramenopiles, and viridaeplantae). Other examples include seaweed, plankton (e.g. , macroplankton, mesoplankton, microplankton, ankton, picoplankton, and femptoplankton), phytoplankton, bacteria (e.g., gram positive bacteria, gram negative bacteria, and ophiles), human cells, mammalian cells, yeast and/or mixtures of these. There may be several bio-components, for example there may be several bacteria lized to generate different products useful for producing a current from different or the same components ofthe fuel. For example, fermentation methods and fermenting organisms discussed herein can be utilized to produce the secondary product.

Some species of rganisms that can be used to produce the secondary fuel in the indirect sugar fuel cell are: Clostridium saccharobulylacetonicum, idium saccharoperbulylacetonicum, Clostridium saccharobulylicum, Clostridium puniceum, Clostridium beijernckii, Clostridium acetobulylicum, Clostridium aurantibulyricum, Clostridiumfelsineum, Clostridium bulyricum, Geobacter species, strains of the genus omyces spp. e.g., omyces cerevisiae (baker’s yeast), Saccharomyces distaticus, Saccharomyces , strains ofthe genus Kluyveromyces, e.g., s Kluyveromyces mamianus, Kluyveromyces fragilis, strains of the genus Candida, e.g., Candida pseudotropicalis, and Candida brassicae, Pichia stipitis (a relative of Candida shehatae), strains of the genus Clavispora, e.g., species Clavispora lusitaniae and Clavispora opuntiae, strains of the genus Pachysolen, e.g., species Pachysolen tannophilus, and strains of the genus Bretannomyces, e.g., species Bretannomyces m'i (Philippidis, G. P., 1996, Cellulose version technology, in Handbook on Bioethanol: Production and Utilization, Wyman, C.E., ed., Taylor & Francis, Washington, DC, 179-212).

Commercially ble yeasts the may be used for the formation of secondary fuel e, for example, Red Star®/Lesaffre Ethanol Red able from Red Star/Lesaffre, USA) FALI® (available from Fleischmann’s Yeast, a division of Burns Philip Food Inc., USA), SUPERSTART® (available from Alltech, now Lalemand), GERT STRAND® (available from Gert Strand AB, Sweden) and FERMOL® (available from DSM Specialties).

Biological fuel cells are devices capable of directly orming a chemical fuel to electrical energy via electrochemical reactions involving biochemical pathways. Generally this involves enzymes or active parts of enzymes for catalysis.

The enzymes can be within a living organism (e.g., microbial fuel cells) or can be outside of a living cell (e.g., enzyme fuel cells). shows a diagrammatic view of a lized half-cell for a biological fuel cell. A supplied fuel is contacted with a ical component which oxidizes the fuel and creates waste that is removed. The electrons released from the fuel are transferred from the biological component to a mediator which either diffuses to or is associated with the electrode where the mediator is oxidized to its original state releasing an electron to an external circuit.

The t side of the fuel cell is not shown. Some oxidants can be, for example, 02, supplied by air, or peroxides (e.g., hydrogen peroxide, organic peroxides, inorganic peroxides). Some biological fuel cells do not require a mediator; in such cells the electron is transferred directly from the biological component to the electrode. In some biological fuel cells the anode reaction with oxygen is catalyzed by a biological component. Some biological fuel cells have been described, for example by Derek Lovely in "The microbe electric: conversion of organic matter to electricity", Current Opinions in Biotechnology, 2008, Volume 19, pages 1-8, or in US. patent No. 8,283,076 filed May 18, 2007; the entire disclosure in these references are incorporated by nce herein.

The fuel used in the ical fuel cell can be the saccharification products from biomass as previously discussed. Especially in cases where organisms are ed (e.g., microbial fuel cells) other nutrients and media components can be added 2012/070624 to the fuels, for example ions (e.g., sodium, potassium, iron, magnesium, manganese, zinc, copper), phosphates, sulfates, a, urea, amino acids, proteins, Vitamins, buffers, organic acids, nic acids, c bases, inorganic bases, nutrient rich extracts(e.g., yeast extracts, meat extracts and vegetable extracts). Additionally the temperature and pH can be lled. For example temperatures between 10 and 70 °C can be used (e.g., between about 10 and 60 °C between about 10 and 50 °C, between about 10 and 40 °C, between about 20 and 70 °C, between about 20 and 60 °C, between about 20 and 50 °C, between about 20 and 40 °C, between about 30 and 70 °C, between about 30 and 60 °C, between about 30 and 50 °C, between about 30 and 40 oC). The pH can be between about 3 and 10 (e.g., between about 3 and 9, between about 3 and 8, between about 3 and 7, between about 3 and 6, between about 3 and 5, between about 4 and 9, between about 4 and 8, between about 4 and 7, between about 5 and 9, between about 5 and 8, between about 5 and 7).

Examples of organisms that can be useful in biological fuel cells are s of geobacter, proteus vulgaris, Desulphovibrio desulphuricans, E. coli, bacillus succinogenes, Desulphovibrio vulgaris, Shewanella putrefaciens and Rhodoferax ferrireducens.

Examples of enzymes that can be useful in biological fuel cells are glucose oxidase, alcoholdehydrogenase, dedehydrogenase, formate dehydrogenase, oxidoreductase, diaphorase, flavor-oxido-reductase, laccase, microperoxidase, glucose dehydrogenase, hydrogenase, peroxidases, reconstituted enzymes from this list and combinations thereof.

MECHANICAL TREATMENTS Biomass feedstock (e.g., cellulosic and/or lignocellulosic material) can be mechanically treated prior to or after other treatments. Methods of ically treating the carbohydrate-containing material include, for example, g or grinding. Milling may be performed using, for example, a hammer mill, ball mill, colloid mill, conical or cone mill, disk mill, edge mill, Wiley mill, grist mill or other mills. Grinding may be performed using, for example, a g/impact type grinder.

Some exemplary grinders include stone grinders, pin grinders, coffee rs, and burr grinders. Grinding or milling may be provided, for example, by a reciprocating pin or other element, as is the case in a pin mill. Other mechanical treatment methods include mechanical ripping or tearing, other s that apply pressure to the fibers, and air attrition milling. Suitable mechanical treatments further include any other que that continues the disruption of the internal structure of the material that was initiated by the previous processing steps. ical feed preparation systems can be configured to produce streams with specific characteristics such as, for example, specific m sizes, c length-to-width, or specific surface areas ratios. Physical preparation can increase the rate of reactions, improve the nt of material, improve the irradiation profile of the material, improve the radiation uniformity of the material, or reduce the processing time required by opening up the materials and making them more accessible to processes and/or reagents, such as reagents in a solution.

The bulk y of feedstocks can be controlled (e.g., increased). In some situations, it can be desirable to prepare a low bulk density material, e.g., by densifying the material (e.g., densification can make it easier and less costly to transport to another site) and then reverting the al to a lower bulk density state (e.g. , after transport). The material can be densified, for example from less than about 0.2 g/cc to more than about 0.9 g/cc (e.g., less than about 0.3 to more than about 0.5 g/cc, less than about 0.3 to more than about 0.9 g/cc, less than about 0.5 to more than about 0.9 g/cc, less than about 0.3 to more than about 0.8 g/cc, less than about 0.2 to more than about 0.5 g/cc). For example, the material can be densified by the s and equipment disclosed in U.S. Pat. No. 7,932,065 to Medoff and International Publication No. (which was filed October 26, 2007, was published in English, and which ated the United States), the full disclosures of which are orated herein by reference. Densified materials can be processed by any of the methods described herein, or any al processed by any of the methods described herein can be subsequently densified.

In some embodiments, the material to be processed is in the form of a fibrous material that includes fibers provided by shearing a fiber source. For example, the shearing can be performed with a rotary knife cutter.

For e, a fiber source, e.g., that is recalcitrant or that has had its recalcitrance level reduced, can be sheared, e.g., in a rotary knife cutter, to provide a first fibrous material. The first fibrous material is passed through a first screen, e.g., having an average opening size of 1.59 mm or less (1/16 inch, 0.0625 inch), provide a second fibrous material. If desired, the fiber source can be cut prior to the shearing, WO 96452 e.g., with a shredder. For example, when a paper is used as the fiber source, the paper can be first cut into strips that are, e.g., 1/4- to 1/2-inch wide, using a shredder, e.g., a counter-rotating screw er, such as those manufactured by Munson (Utica, N.Y.).

As an ative to shredding, the paper can be reduced in size by g to a desired size using a guillotine cutter. For example, the guillotine cutter can be used to cut the paper into sheets that are, e.g., 10 inches wide by 12 inches long.

In some embodiments, the shearing of the fiber source and the passing of the resulting first fibrous material through a first screen are performed concurrently. The shearing and the passing can also be performed in a batch-type s.

For example, a rotary knife cutter can be used to concurrently shear the fiber source and screen the first fibrous material. A rotary knife cutter includes a hopper that can be loaded with a shredded fiber source prepared by shredding a fiber source.

In some implementations, the feedstock is physically treated prior to saccharification and/or fermentation. Physical treatment processes can e one or more of any of those described herein, such as mechanical treatment, chemical treatment, irradiation, sonication, oxidation, pyrolysis or steam explosion. Treatment methods can be used in combinations of two, three, four, or even all of these technologies (in any order). When more than one treatment method is used, the s can be applied at the same time or at different times. Other processes that change a molecular structure of a biomass feedstock may also be used, alone or in combination with the processes disclosed herein.

Mechanical ents that may be used, and the characteristics of the mechanically treated feedstocks, are described in further detail in U.S. Serial No. 13/276,192, filed October 18, 2011, the full sure of which is hereby incorporated herein by reference.

In addition to this size reduction, which can be performed initially and/or later during processing, mechanical treatment can also be advantageous for "opening up," "stressing," breaking or shattering the ock materials, making the cellulose of the materials more susceptible to chain scission and/or disruption of crystalline structure during the structural modification treatment.

The biomass can be in a dry form, for example with less than about % moisture content (e.g., less than about 20 %, less than about 15 %, less than about 10 % less than about 5 %, less than about 4%, less than about 3 %, less than about 2 % or even less than about 1 %). The biomass can also be delivered in a wet state, for example as a wet solid, a slurry or a suspension with at least about 10 wt% solids (e.g., at least about 20 wt.%, at least about 30 wt. %, at least about 40 wt.%, at least about 50 wt.%, at least about 60 wt.%, at least about 70 wt.%).

The processes disclosed herein can utilize low bulk density materials, for e cellulosic or ellulosic feedstocks that have been physically pretreated to have a bulk density of less than about 0.75 g/cm3, e.g., less than about 0.7, 0.65, 0.60, 0.50, 0.35, 0.25, 0.20, 0.15, 0.10, 0.05 or less, e.g., less than about 0.025 g/cm3.

Bulk density is determined using ASTM D1895B. Briefly, the method involves filling a measuring cylinder ofknown volume with a sample and obtaining a weight of the sample. The bulk density is calculated by dividing the weight of the sample in grams by the known volume of the cylinder in cubic centimeters. If desired, low bulk density als can be densified, for example, by methods described in US. Pat. No. 7,971,809 to Medoff, the full disclosure of which is hereby incorporated by nce.

In some cases, the biomass can be screened through a mesh or perforated plate with a desired opening size, for example, less than about 6.35 mm (14 inch, 0.25 inch), (e.g., less than about 3.18 m (1/8 inch, 0.125 inch), less than about 1.59 mm (1/16 inch, 0.0625 inch), is less than about 0.79 mm (1/32 inch, 0.03125 inch), e.g., less than about 0.51 mm (1/50 inch, 0.02000 inch), less than about 0.40 mm (1/64 inch, 0.015625 inch), less than about 0.23 mm (0.009 inch), less than about 0.20 mm (1/128 inch, 0.0078125 inch), less than about 0.18 mm (0.007 inch), less than about 0.13 mm (0.005 inch), or even less than about 0.10 mm (1/256 inch, 0.00390625 inch)).

Screening of biomass al can also be by a manual method, for example by an operator or mechanoid (e.g., a robot equipped with a color, ivity or other sensor) that removes unwanted material. Screening can also be by magnetic screening n a magnet is ed near the conveyed material and the magnetic al is removed magnetically.

Optionally, prior to further processing, the biomass material can be heated, for example by IR radiation, microwaves, combustion (e.g., gas, coal, oil, s), resistive heating and/or ive heating. Heating can be, for example, for the purpose of drying the material. In the case of drying the material, this can also be facilitated, with or without heating, by the movement of a gas (e.g., air, oxygen, nitrogen, He, C02, Argon) over and/or through the biomass.

Optionally, the biomass can be cooled prior to or after mechanical treatment.

Cooling material is described in US Pat. No. 7,900,857 to Medoff, the disclosure of which in incorporated herein by nce.

ION ENT In some cases, the feedstock may be irradiated to modify its structure and thereby reduce its recalcitrance. Irradiation may, for example, reduce the average molecular weight ofthe feedstock, change the crystalline structure ofthe feedstock, change the fimctionalization ofthe feedstock (e.g., by oxidation) and/or increase the e area and/or porosity of the ock.

Various other irradiating devices may be used in the methods disclosed herein, including field tion sources, ostatic ion separators, field ionization generators, thermionic emission sources, microwave discharge ion sources, recirculating or static accelerators, dynamic linear accelerators, van de Graaff accelerators, and folded tandem accelerators. Such devices are disclosed, for example, in U.S. Pat. No. 7,931,784 to Medoff, the complete disclosure ofwhich is incorporated herein by reference.

A beam of electrons can be used as the radiation source. A beam of electrons has the advantages of high dose rates (e.g., l, 5, or even 10 Mrad per second), high throughput, less containment, and less confinement equipment. Electron beams can also have high electrical efficiency (e.g., 80%), ng for lower energy usage relative to other radiation methods, which can translate into a lower cost of operation and lower greenhouse gas emissions corresponding to the smaller amount of energy used. Electron beams can be generated, e.g., by electrostatic generators, e tors, transformer generators, low energy rators with a scanning system, low energy accelerators with a linear cathode, linear accelerators, and pulsed accelerators.

Electrons can also be more nt at causing changes in the molecular structure of carbohydrate-containing materials, for example, by the mechanism of chain scission. In addition, electrons having energies of 0.5-10 MeV can ate low density materials, such as the biomass materials described herein, e.g., materials having a bulk density of less than 0.5 g/cm3, and a depth of 03-10 cm. Electrons as an ionizing radiation source can be useful, e.g., for relatively thin piles, layers or beds of materials, e.g., less than about 0.5 inch, e.g., less than about 0.4 inch, 0.3 inch, 0.25 inch, or less than about 0.1 inch. In some embodiments, the energy of each electron ofthe electron beam is from about 0.3 MeV to about 2.0 MeV (million electron volts), e.g., from about 0.5 MeV to about 1.5 MeV, or from about 0.7 MeV to about 1.25 MeV. s of irradiating als are discussed in U.S. Pat. App. Pub. 2012/01000577 A1, filed October 18, 2011, the entire disclosure ofwhich is herein incorporated by reference.

Electron beam irradiation devices may be procured commercially from Ion Beam Applications, n-la-Neuve, Belgium or the Titan Corporation, San Diego, CA. Typical electron energies can be 0.5 MeV, 1 MeV, 2 MeV, 4.5 MeV, 7.5 MeV, or 10 MeV. Typical electron beam irradiation device power can be 1 KW, 5 KW, 10 KW, 20 KW, 50 KW, 60 KW, 70 KW, 80 KW, 90 KW, 100 KW, 125 KW, 150 KW, 175 KW, 200 KW, 250 KW, 300 KW, 350 KW, 400 KW, 450 KW, 500 KW, 600 KW, 700 KW, 800 KW, 900 KW or even 1000 KW.

Tradeoffs in considering electron beam irradiation device power cations include cost to operate, capital costs, depreciation, and device footprint. ffs in ering exposure dose levels of electron beam irradiation would be energy costs and environment, safety, and health (ESH) concerns. Typically, generators are housed in a vault, e.g. of lead or concrete, especially for production from X-rays that are generated in the process. ffs in considering electron es include energy costs.

The electron beam irradiation device can produce either a fixed beam or a scanning beam. A scanning beam may be advantageous with large scan sweep length and high scan speeds, as this would effectively replace a large, fixed beam width.

Further, available sweep widths of 0.5 m, 1 m, 2 m or more are available.

In some embodiments, two or more radiation sources are used, such as two or more ionizing radiation sources. For example, s can be treated, in any order, with a beam of electrons, followed by gamma radiation and UV light having wavelengths from about 100 nm to about 280 nm. In some embodiments, samples are treated with three ionizing radiation sources, such as a beam of electrons, gamma radiation, and energetic UV light. The biomass is conveyed through the irradiation zone (354 in where it can be irradiated, for example by ons. It is generally preferred that the bed of biomass al has a relatively uniform thickness, as previously described, while being irradiated.

Effectiveness of changing the molecular/supermolecular structure and/or reducing the recalcitrance of the carbohydrate-containing biomass s on the electron energy used and the dose applied, while exposure time depends on the power and dose.

In some embodiments, the irradiating (with any radiation source or a combination of sources) is performed until the material receives a dose of at least about 0.05 Mrad, e.g., at least about 0.1, 0.25, 0.5, 0.75, 1.0, 2.5, 5.0, 7.5, 10.0, 15, 20, , 30, 40, 50, 60, 70, 80, 90, 100, 125, 150, 175, or 200 Mrad. In some embodiments, the irradiating is performed until the material receives a dose of n 0.1 - 100 Mrad, 1 - 200, 5 — 200, 10 — 200, 5 — 150, 50 - 150, 100 - 200, 100 - 150, 80 - 120, 5 — 100, 5 — 50, 5 — 40,10 — 50,10 — 75,15 — 50, 20 — 35 Mrad.

In some embodiments, the irradiating is performed at a dose rate of between .0 and 1500.0 kilorads/hour, e.g., between 10.0 and 750.0 kilorads/hour or between 50.0 and 350.0 kilorads/hours. In other embodiments the irradiation is performed at a dose rate ofbetween 10 and 10000 kilorads/hr, between 100 and 1000 kilorad/hr, or between 500 and 1000 ds/hr.

In some implementations, it is desirable to cool the material during irradiation.

For example, the al can be cooled while it is being ed, for example by a screw extruder or other conveying equipment.

Radiation can be applied while the osic and/or lignocellulosic al is exposed to air, oxygen-enriched air, or even oxygen , or blanketed by an inert gas such as nitrogen, argon, or helium. When maximum oxidation is desired, an oxidizing environment is utilized, such as air or oxygen and the distance from the radiation source is optimized to maximize reactive gas formation, e.g., ozone and/or oxides of nitrogen.

SONICATION, PYROLYSIS, OXIDATION, STEAM ION If desired, one or more sonication, pyrolysis, oxidative, or steam explosion processes can be used in addition to or instead of irradiation to reduce the recalcitrance of the feedstock. These processes are described in detail in U.S. Serial No. 12/429,045, the full disclosure ofwhich is incorporated herein by reference.

SACCHARIFICATION The treated biomass materials can be saccharified, generally by combining the al and a cellulase enzyme in a fluid medium, e.g., an aqueous solution. In some cases, the material is boiled, steeped, or cooked in hot water prior to saccharification, as described in U.S. Pat. App. Pub. 2012/01000577 A1, filed October 18, 2011.

The saccharification process can be partially or completely performed in a tank (e.g., a tank having a volume of at least 4000, 40,000, or 500,000 L) in a manufacturing plant, and/or can be lly or completely performed in transit, e.g., in a rail car, tanker truck, or in a supertanker or the hold of a ship. The time required for complete saccharification will depend on the process conditions and the carbohydrate-containing material and enzyme used. If saccharification is performed in a manufacturing plant under controlled ions, the cellulose may be substantially entirely converted to sugar, e.g., glucose in about 12-96 hours. If saccharification is performed partially or completely in transit, saccharification may take longer.

It is generally preferred that the tank contents be mixed during saccharification, e.g., using jet mixing as described in International App. No. , filed May 18, 2010, which was published in English as WC 2010/135380 and designated the United States, the full disclosure ofwhich is incorporated by reference herein.

The addition of tants can e the rate of saccharification. Examples of surfactants include non-ionic surfactants, such as a Tween® 20 or Tween® 80 polyethylene glycol tants, ionic surfactants, or amphoteric surfactants.

It is generally red that the concentration of the sugar solution ing from saccharification be relatively high, e.g. than 40%, or greater than 50, 60, , greater 70, 80, 90 or even greater than 95% by weight. Water may be removed, e.g., by evaporation, to increase the concentration of the sugar solution. This s the volume to be shipped, and also inhibits microbial grth in the solution.

Alternatively, sugar solutions of lower concentrations may be used, in which case it may be ble to add an antimicrobial additive, e.g., a broad um antibiotic, in a low concentration, e.g., 50 to 150 ppm. Other le antibiotics include amphotericin B, ampicillin, chloramphenicol, ciprofloxacin, gentamicin, hygromycin B, kanamycin, neomycin, llin, puromycin, streptomycin.

Antibiotics will inhibit growth of microorganisms during transport and storage, and can be used at appropriate concentrations, e.g., n 15 and 1000 ppm by weight, e.g., between 25 and 500 ppm, or between 50 and 150 ppm. If desired, an antibiotic can be included even if the sugar concentration is relatively high. atively, other additives with anti-microbial or preservative properties may be used. ably the antimicrobial additive(s) are rade.

A relatively high concentration on can be obtained by limiting the amount ofwater added to the ydrate-containing material with the enzyme. The concentration can be controlled, e.g., by controlling how much saccharification takes place. For example, concentration can be increased by adding more carbohydrate- containing material to the solution. In order to keep the sugar that is being produced in solution, a surfactant can be added, e.g., one of those discussed above. Solubility can also be increased by increasing the temperature of the solution. For example, the solution can be maintained at a temperature of C, C, or even higher.

SUGARS In the processes described herein, for example after saccharification, sugars (e.g., glucose and xylose) can be isolated. For example sugars can be isolated by precipitation, crystallization, chromatography (e.g., simulated moving bed chromatography, high pressure chromatography), centrifugation, extraction, any other isolation method known in the art, and combinations thereof.

FERMENTATION Yeast and Zymomonas bacteria, for example, can be used for tation or conversion of s) to alcohol(s). Other microorganisms are discussed below. The optimum pH for fermentations is about pH 4 to 7. For example, the optimum pH for yeast is from about pH 4 to 5, while the optimum pH for Zymomonas is from about pH 5 to 6. Typical fermentation times are about 24 to 168 hours (e.g., 24 to 96 hrs) with temperatures in the range of 20°C to 40°C (e.g., 26°C to 40°C), however thermophilic microorganisms prefer higher temperatures.

In some embodiments, e.g., when anaerobic organisms are used, at least a portion of the fermentation is conducted in the absence of oxygen, e.g., under a blanket of an inert gas such as N2, Ar, He, C02 or es thereof. Additionally, the mixture may have a constant purge of an inert gas flowing through the tank during part of or all of the fermentation. In some cases, anaerobic condition, can be achieved or ined by carbon dioxide production during the fermentation and no additional inert gas is needed.

In some embodiments, all or a portion of the fermentation process can be upted before the low molecular weight sugar is completely converted to a product (e.g., ethanol). The intermediate fermentation products include sugar and carbohydrates in high concentrations. The sugars and carbohydrates can be isolated via any means known in the art. These ediate fermentation products can be used in preparation of food for human or animal consumption. Additionally or alternatively, the intermediate tation products can be ground to a fine particle size in a stainless-steel laboratory mill to produce a flour-like substance.

Jet mixing may be used during fermentation, and in some cases saccharification and fermentation are performed in the same tank. nts for the microorganisms may be added during saccharification and/or fermentation, for example the ased nutrient packages described in U.S. Pat.

App. Pub. 2012/0052536, filed July 15, 2011, the te disclosure of which is incorporated herein by reference.

Mobile fermenters can be utilized, as bed in Intemational App. No. (which was filed July 20, 2007, was hed in English as and designated the United States), the contents ofwhich is incorporated herein in its entirety. Similarly, the saccharification equipment can be mobile. Further, saccharification and/or fermentation may be med in part or entirely during transit.

DISTILLATION After fermentation, the resulting fluids can be distilled using, for example, a "beer column" to separate ethanol and other alcohols from the majority of water and residual solids. The vapor exiting the beer column can be, e.g. , 35% by weight ethanol and can be fed to a rectification column. A mixture of nearly opic (92.5%) ethanol and water from the rectification column can be purified to pure (99.5%) ethanol using vapor-phase molecular sieves. The beer column bottoms can be sent to the first effect of a three-effect evaporator. The rectification column reflux condenser can provide heat for this first effect. After the first effect, solids can be separated using a centrifuge and dried in a rotary dryer. A portion (25%) of the centrifuge effluent can be recycled to fermentation and the rest sent to the second and third evaporator effects. Most of the evaporator sate can be returned to the process as fairly clean sate with a small n split off to waste water treatment to prevent build-up of low-boiling compounds.

INTERMEDIATES AND PRODUCTS Using the processes described herein, the biomass material can be converted to one or more products, such as energy, fuels, foods and materials. Specific examples ofproducts include, but are not limited to, hydrogen, sugars (e.g., e, , arabinose, mannose, ose, fructose, disaccharides, oligosaccharides and polysaccharides), alcohols (e.g., dric alcohols or dihydric alcohols, such as ethanol, n-propanol, anol, sec-butanol, tert-butanol or n-butanol), hydrated or hydrous alcohols (e.g., containing greater than 10%, 20%, 30% or even r than 40% water), biodiesel, organic acids, hydrocarbons (e.g., methane, ethane, propane, isobutene, pentane, n-hexane, biodiesel, bio-gasoline and mixtures thereof), co- products (e.g., proteins, such as cellulolytic proteins (enzymes) or single cell proteins), and mixtures of any of these in any combination or relative tration, and optionally in combination with any additives (e.g., fuel ves). Other examples include carboxylic acids, salts of a carboxylic acid, a mixture of carboxylic acids and salts of carboxylic acids and esters of carboxylic acids (e.g., methyl, ethyl and n-propyl esters), ketones (e.g., acetone), aldehydes (e.g., acetaldehyde), alpha and beta unsaturated acids (e.g., acrylic acid) and olefins (e.g., ethylene). Other alcohols and alcohol derivatives include propanol, propylene glycol, l,4-butanediol, 1,3- propanediol, sugar alcohols (e.g., itol, glycol, ol, sorbitol threitol, arabitol, ribitol, mannitol, dulcitol, fucitol, iditol, isomalt, maltitol, lactitol, xylitol and other polyols), and methyl or ethyl esters of any of these alcohols. Other products include methyl acrylate, methylmethacrylate, lactic acid, citric acid, formic acid, acetic acid, propionic acid, butyric acid, succinic acid, c acid, caproic acid, 3- hydroxypropionic acid, palmitic acid, stearic acid, oxalic acid, malonic acid, glutaric acid, oleic acid, linoleic acid, glycolic acid, gamma-hydroxybutyric acid, and es thereof, salts of any of these acids, mixtures of any of the acids and their respective salts. Many of the products ed, such as ethanol or n-butanol, can be utilized as a fuel for powering cars, trucks, tractors, ships or trains, e.g., as an internal combustion fuel or as a fuel cell feedstock. Many of the products obtained can also be utilized to power aircraft, such as planes, e.g., having jet engines or helicopters. In addition, the ts described herein can be utilized for electrical power generation, e.g., in a conventional steam generating plant or in a fuel cell plant.

Other intermediates and products, including food and pharmaceutical products, are described in U.S. App. No. 12/417,900 filed April 3, 2009, the full disclosure of which is hereby incorporated by reference herein.

CARBOHYDRATE CONTAINING MATERIALS IOMASS MATERIALS As used herein, the term "biomass als" is used interchangeably with the term "carbohydrate-containing materials", and includes lignocellulosic, cellulosic, starchy, and microbial materials. Any of the methods described herein can be practiced with es of any biomass materials described herein.

Lignocellulosic materials include, but are not limited to, wood, particle board, forestry wastes (e.g., sawdust, aspen wood, wood chips), grasses, (e.g., switchgrass, thus, cord grass, reed canary , grain es, (e.g., rice hulls, oat hulls, wheat chaff, barley hulls), agricultural waste (e.g., silage, canola straw, wheat straw, barley straw, oat straw, rice straw, jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn , soybean stover, corn fiber, alfalfa, hay, coconut hair), sugar processing residues (e.g., bagasse, beet pulp, agave bagasse), , algae, seaweed, manure, , and mixtures of any of these.

In some cases, the lignocellulosic material includes comcobs. Ground or hammermilled comcobs can be spread in a layer of vely uniform thickness for irradiation, and after irradiation are easy to disperse in the medium for further sing. To facilitate harvest and collection, in some cases the entire corn plant is used, including the corn stalk, corn kernels, and in some cases even the root system of the plant.

Advantageously, no additional nutrients (other than a nitrogen source, e.g., urea or ammonia) are required during tation of comcobs or cellulosic or lignocellulosic materials containing significant amounts of comcobs. 2012/070624 Comcobs, before and after comminution, are also easier to convey and disperse, and have a lesser tendency to form explosive mixtures in air than other cellulosic or lignocellulosic materials such as hay and grasses.

Cellulosic materials include, for example, paper, paper ts, paper waste, paper pulp, pigmented papers, loaded papers, coated papers, filled papers, magazines, printed matter (e.g., books, catalogs, manuals, labels, calendars, greeting cards, brochures, prospectuses, newsprint), r paper, polycoated paper, card stock, cardboard, paperboard, als having a high oc-cellulose content such as cotton, and mixtures of any of these. For example paper products as described in U.S. App.

No. 13/396,365 ("Magazine Feedstocks" by Medoff et al., filed February 14, 2012), the full disclosure of which is incorporated herein by reference.

Cellulosic als can also include lignocellulosic materials which have been de-lignified.

Starchy als include starch itself, e.g., corn starch, wheat starch, potato starch or rice starch, a derivative of starch, or a material that includes starch, such as an edible food product or a crop. For e, the starchy material can be arracacha, buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum, regular household potatoes, sweet potato, taro, yams, or one or more beans, such as favas, lentils or peas.

Blends of any two or more starchy materials are also y materials. Mixtures of starchy, cellulosic and or lignocellulosic materials can also be used. For example, a biomass can be an entire plant, a part of a plant or different parts of a plant, e.g., a wheat plant, cotton plant, a corn plant, rice plant or a tree. The starchy materials can be d by any of the methods described herein. ial materials include, but are not d to, any lly occurring or genetically modified microorganism or organism that contains or is capable of providing a source of carbohydrates (e.g., cellulose), for example, protists, e.g., animal protists (e.g., protozoa such as flagellates, amoeboids, ciliates, and oa) and plant protists (e.g., algae such alveolates, chlorarachniophytes, cryptomonads, euglenids, glaucophytes, haptophytes, red algae, stramenopiles, and viridaeplantae).

Other examples include seaweed, plankton (e.g., macroplankton, mesoplankton, lankton, nanoplankton, picoplankton, and femptoplankton), phytoplankton, bacteria (e.g., gram positive ia, gram negative bacteria, and extremophiles), yeast and/or mixtures of these. In some instances, microbial biomass can be obtained from natural sources, e.g., the ocean, lakes, bodies of water, e.g., salt water or fresh water, or on land. Alternatively or in addition, microbial biomass can be obtained from culture systems, e.g., large scale dry and wet culture and fermentation systems.

In other embodiments, the biomass materials, such as cellulosic, starchy and lignocellulosic feedstock materials, can be obtained from transgenic microorganisms and plants that have been modified with respect to a wild type y. Such modifications may be, for example, through the iterative steps of selection and ng to obtain desired traits in a plant. Furthermore, the plants can have had genetic material removed, modified, silenced and/or added with respect to the wild type variety. For example, genetically modified plants can be produced by recombinant DNA s, where genetic modifications include introducing or modifying specific genes from parental varieties, or, for example, by using transgenic breeding wherein a specific gene or genes are introduced to a plant from a different s of plant and/or bacteria. Another way to create genetic variation is through mutation ng n new alleles are artificially created from endogenous genes.

The artificial genes can be created by a variety ofways including treating the plant or seeds with, for example, al mutagens (e.g., using alkylating agents, es, alkaloids, peroxides, formaldehyde), irradiation (e.g., X-rays, gamma rays, neutrons, beta particles, alpha particles, protons, deuterons, UV radiation) and temperature shocking or other external stressing and subsequent selection techniques. Other methods ofproviding modified genes is through error prone PCR and DNA shuffling followed by insertion of the desired modified DNA into the desired plant or seed. s of introducing the desired genetic variation in the seed or plant include, for example, the use of a bacterial carrier, biolistics, calcium phosphate precipitation, electroporation, gene splicing, gene silencing, lipofection, microinjection and viral rs. Additional genetically modified materials have been described in U.S.

Application Serial No 13/3 96,3 69 filed ry 14, 2012 the full disclosure of which is incorporated herein by reference.

SACCHARIFYING AGENTS Suitable cellulolytic enzymes include cellulases from s in the genera Bacillus, Caprinus, Myceliophthora, Cephalosporium, idium, Penicillium, illus, Pseudomonas, Humicola, Fusarium, Thielavia, Acremonium, Chrysosporium and Trichoderma, ally those produced by a strain selected from the species illuS (see, e.g., EP Pub. No. 0 458 162), la insolenS (reclassified as Scytalidium thermophilum, see, e.g., US. Pat. No. 4,435,307), CaprinuS cinereuS, Fusarium oxySporum, Myceliophthora thermophila, MeripiluS giganteuS, Thielavia terrestriS, nium Sp. (including, but not limited to, A. perSicinum,A. acremonium,A. brachypenium,A. dichromosporum, A. 0bclavatum,A. pinkertoniae, A. riseum, A. incoloratum, and A. furatum). Preferred strains e Humicola insolenS DSM 1800, Fusarium oxySporum DSM 2672, Myceliophthora thermophila CBS 117.65, Cephalosporium Sp. RYM-202, Acremom'um Sp. CBS 478.94, Acremom'um Sp. CBS 265.95, Acremom'um persicinum CBS 169.65, Acremonium nium AHU 9519, Cephalosporium Sp. CBS 535.71, Acremom'um brachypenium CBS 866.73, Acremonium mosporum CBS 683.73, m'um obclavatum CBS 311.74, Acremom'um pinkertoniae CBS 157.70, Acremom'um riseum CBS 134.56, Acremonium incoloratum CBS 146.62, and Acremoniumfuratum CBS 299.70H. Cellulolytic enzymes may also be obtained from Chrysosporium, ably a strain of Chrysosporium lucknowense. Additional strains that can be used include, but are not limited to, Trichoderma cularly T. viride, T. reesei, and T. koningii), alkalophilic Bacillus (see, for example, US. Pat.

No. 890 and EP Pub. No. 0 458 162), and Streptomyces (see, e.g., EP Pub. No. 0 458 162).

FERMENTATION AGENTS The microorganism(s) used in fermentation can be naturally-occurring microorganisms and/or engineered microorganisms. These fermentation agents can be used, for example, to convert a primary fuel to a secondary fuel to be used for energy generation in an indirect fuel cell. Of the fermentation agents can be used to convert sugars or intermediates not used in fuel cells bed in the methods herein.

Examples of microorganism can be a bacterium (including, but not limited to, e.g., a cellulolytic bacterium), a fungus, (including, but not limited to, e.g., a yeast), a plant, a protist, e.g., a protozoa or a fungus-like protest (including, but not limited to, e.g., a slime mold), or an alga. When the organisms are compatible, mixtures of organisms can be utilized.

Suitable fermenting microorganisms have the ability to convert carbohydrates, such as glucose, fructose, xylose, arabinose, mannose, galactose, oligosaccharides or polysaccharides into fermentation products. Fermenting microorganisms include strains of the genus Sacchromyces spp. (including, but not limited to, S. cerevisiae (baker’s yeast), S. distaticus, S. ), the genus Kluyveromyces, (including, but not limited to, K. marxianus, K. fragilis), the genus Candida ding, but not limited to, C. pseudotropicalis, and C. cae), Pichia stipitis (a relative of Candida ae), the genus Clavispora (including, but not limited to, C. niae and C. opuntiae), the genus Pachysolen (including, but not limited to, P. hilus), the genus Bretannomyces (including, but not limited to, e.g. B. nii (Philippidis, G. P., 1996, Cellulose bioconversion logy, in Handbook on Bioethanol: Production and Utilization, Wyman, C.E., ed., Taylor & Francis, Washington, DC, 179-212)). Other suitable microorganisms e, for example, Zymomonas mobilis, Clostridium spp. (including, but not d to, Clostridium thermocellum (Philippidis, 1996, supra), Clostridium saccharobulylacetonicum, Clostridium felsineum,Clostridium saccharobulylicum, Clostridium Puniceum, Clostridium beijernckii, Clostridium ulylicum, and Clostridium aurantibulylicum), Moniliella pollinis, Yarrowia lipolytica, Aureobasidium sp., Trichosporonoides sp., Trigonopsis variabilis, Trichosporon sp., Moniliellaacetoabutans sp., a variabilis, Candida magnoliae, Ustilaginomycetes sp., Pseudozyma tsukubaensis, yeast species of genera Zygosaccharomyces, omyces, Hansenula and Pichia, and fungi of the dematioid genus Torula.

Many such microbial strains are publicly available, either commercially or through depositories such as the ATCC (American Type Culture Collection, as, Virginia, USA), the NRRL (Agricultural Research Sevice Culture Collection, Peoria, Illinois, USA), or the DSMZ (Deutsche ng von Mikroorganismen und Zellkulturen GmbH, Braunschweig, Germany), to name a few.p Commercially available yeasts include, for example, Red Star®/Lesaffre Ethanol Red (available from Red Star/Lesaffre, USA), FALI® (available from Fleischmann’s Yeast, a division of Burns Philip Food Inc., USA), SUPERSTART® (available from Alltech, now Lalemand), GERT STRAND® (available from Gert Strand AB, Sweden) and FERMOL® (available from DSM Specialties).

WO 96452 Other than in the examples herein, or unless otherwise expressly specified, all ofthe numerical ranges, amounts, values and percentages, such as those for amounts of materials, elemental contents, times and temperatures of reaction, ratios of amounts, and others, in the following portion of the specification and ed claims may be read as if prefaced by the word " even though the term "about" may not expressly appear with the value, amount, or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number ofreported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently ns error necessarily resulting from the standard deviation found in its underlying respective testing measurements. Furthermore, when numerical ranges are set forth , these ranges are inclusive of the recited range end points (i.e., end points may be used). When percentages by weight are used herein, the numerical values ed are relative to the total weight.

Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges ed n. For example, a range of "l to " is intended to include all sub-ranges between (and including) the recited minimum value of l and the recited maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. The terms "one," "a," or "an" as used herein are ed to include "at least one" or "one or more," unless otherwise ted.

Any patent, publication, or other disclosure material, in whole or in part, that is said to be incorporated by reference herein is incorporated herein only to the extent that the incorporated material does not conflict with existing definitions, statements, or other disclosure al set forth in this disclosure. As such, and to the extent necessary, the disclosure as itly set forth herein supersedes any conflicting material orated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference , but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing sure material.

While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be tood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.

Claims (12)

WHAT IS CLAIMED IS:

1. A method comprising: enzymatically saccharifying a cellulosic or lignocellulosic material to form a sugar solution with a sugar concentration greater than 40% by weight, wherein the on comprises xylose and glucose; ring the sugar on to a microbial fuel cell containing an anti-scale agent or an anti-fouling agent; and utilizing, the sugar solution at a pH of between 6 and 10 in the microbial fuel cell.

2. The method of claim 1, n, prior to saccharification, the recalcitrance of the cellulosic or lignocellulosic material is reduced relative to that of the cellulosic or ellulosic material in its native state.

3. The method of claim 2 wherein the method of reducing the recalcitrance of the material is selected from the group consisting of mechanically treating, chemically treating, sonicating, zing, ating, oxidizing, steam exploding and combinations thereof.

4. The method of claim 2 wherein the method of reducing recalcitrance of the material comprises irradiation the material with ionizing radiation.

5. The method of claim 4 wherein irradiation comprises irradiation with a dose of at least 10 Mrad.

6. The method of claim 4 wherein ionizing radiation comprises electron beam irradiation.

7. The method of any one of claims 1-6, n the cellulosic or lignocellulosic biomass is selected from the group consisting of: paper, paper products, paper waste, paper pulp, pigmented papers, loaded papers, coated papers, filled papers, magazines, d matter, printer paper, polycoated paper, card stock, ard, paperboard, offal, cotton, wood, particle board, forestry wastes, sawdust, aspen wood, wood chips, s, switchgrass, miscanthus, cord grass, reed canary grass, grain residues, rice hulls, oat hulls, wheat chaff, barley hulls, agricultural waste, silage, canola straw, wheat straw, barley straw, oat straw, rice straw, jute, hemp, flax, bamboo, sisal, abaca, corn cobs, corn stover, soybean stover, corn fiber, alfalfa, hay, coconut hair, sugar processing residues, bagasse, beet pulp, agave bagasse, algae, seaweed, manure, sewage, arracacha, buckwheat, banana, barley, cassava, kudzu, oca, sago, sorghum, potato, sweet potato, taro, yams, beans, favas, lentils, peas, and mixtures of any of these.

8. The method of any one of claims 1-7, further comprising mechanically treating the cellulosic or lignocellulosic material, for e, to reduce the bulk density of the material and/or increase its surface area.

9. The method of any one of claims 1-8 further comprising utilizing an additive in the fuel cell.

10. The method of any one of claims 1-9, wherein the sugar solution is at a pH of between 8 and 10.

11. The method of any one of claims 1-9, wherein the sugar solution is at a pH of between 6 and 8.

12. The method of any one of claims 1-9, wherein the sugar solution is at a pH of between 7 and 8.