JP4101945B2 - Decomposition accelerator for organic waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used for aerobic fermentation treatment of food waste discharged from the restaurant industry such as restaurants, hotels, restaurants, wedding halls, and lunch facilities, and organic waste discharged from food factories. The present invention relates to a decomposition accelerator, a decomposition acceleration method, and a pH adjustment method in an aerobic fermentation treatment process.
[0002]
[Prior art]
Composting organic waste by aerobic fermentation using microorganisms is a technique that has long been performed in the field of agriculture. High-speed composting facilities and bio-type garbage processing devices that apply this principle in engineering are now widely used. In particular, the bio-type garbage processing apparatus has made it possible to perform individual distributed processing, such as quickly processing organic waste at the place where it is generated, instead of the conventional large-scale collective batch concentration processing. This individual dispersion process greatly contributes to improving the hygiene of the storage area until the collection of organic waste, reducing the collection and transportation costs, and improving the collection efficiency of other resource garbage. Such an aerobic fermentation process using microorganisms is not only a resource-saving method with low running cost and low energy consumption, but also can reduce the fermented product to soil as compost, It enabled reuse of organic waste.
[0003]
[Problems to be solved by the invention]
However, the aerobic fermentation treatment method using microorganisms can function only under environmental conditions in which microorganisms that are the main components of organic matter decomposition reactions can actively grow. Therefore, adjustment of the environmental conditions is necessary under inappropriate environmental conditions. Many of the microorganisms involved in the fermentation process have an optimum pH for growth from neutral to weakly alkaline, so that their growth activity is reduced in an acidic environment, and at pH 4-5 or lower, no growth is shown at all. Many. For this reason, when the fall of pH arises in a fermentation process, a decomposition reaction rate will fall and it may cause the substantial delay and stop of a process.
[0004]
Such a decrease in pH during the fermentation process is mainly caused by the generation and accumulation of acidic substances such as organic acids derived from organic waste. This organic acid generation is likely to occur when the oxygen concentration is lowered and becomes anaerobic during the rapid decomposition reaction of organic waste, and operations such as agitation and reversal stop due to an unexpected accident such as a power failure, A similar phenomenon occurs when the supply of oxygen is insufficient.
In order to neutralize these acidic substances and adjust the pH, a mechanism for measuring the pH of the fermented substance using a measuring device in an organic matter treatment apparatus, or an alkaline agent such as slaked lime when the pH value is outside the appropriate range A mechanism for loading was mounted (Japanese Patent Laid-Open Nos. 55-11368 and 1-145388). However, when a mechanism for measuring pH or a mechanism for introducing an alkaline agent is installed in the processing apparatus, the apparatus becomes complicated and expensive, and in particular, for individual distributed processing by a bio-type garbage processing apparatus with a small scale. It is difficult to apply. In addition, it is difficult to accurately measure the pH of a fermented product that is a solid phase reaction system, and if the supply of the alkaline agent is insufficient, the effect cannot be obtained, and the pH increases excessively due to the supply of the excessive alkaline agent. Conversely, there were problems such as causing a decrease in the activity of microorganisms.
[0005]
In addition, there is a method of fermenting organic matter at high speed by filling a fermenter of an organic matter processing apparatus with a pH adjuster that maintains the hydrogen ion concentration from neutral to weakly alkaline and a moisture regulator that fixes microorganisms that decompose organic matter. It has been proposed (Japanese Patent Laid-Open No. 7-303871). However, this moisture regulator has a problem that it takes a week or more for preparation and the production cost is increased.
In the process of fermentation of organic waste, the factor that lowers the pH is the accumulation of organic acid, but the factor that raises the pH is the generation of ammonia. As a good fermentation process proceeds, ammonia produced by protein degradation dissolves in water and becomes ammonium hydroxide, raising the pH. When pH rises to some extent, ammonia volatilizes as ammonia gas, so the pH does not rise so as to hinder fermentation. In the present invention, the present invention has been completed by using an acid-resistant microorganism having sufficient growth activity even in an acidic environment, paying attention to the effect of improving the pH accompanying the degradation of proteins contained in such organic waste. .
[0006]
That is, the present invention relates to (1) an acid-resistant protein-assimilating microorganism selected from χ-proteobacteria Esp-MB8 (deposit number FERM P-16948) or Burkholderia sp. MB11 (deposit number FERM P-16949). a decomposition accelerator for the organic waste composed, organic waste is garbage, the decomposition accelerator, using a decomposition accelerator according to (2) (1), the decomposition of organic waste A method for adjusting the pH in the fermentation process of organic waste, wherein the decomposition method is the soot, and the decomposition accelerator according to (3) (1) is used. The method for adjusting pH, wherein the organic waste is soot.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, acidified organic waste can be aerobically fermented by using an acid-resistant microorganism as a decomposition accelerator.
The acid-resistant microorganism used in the present invention may be either an acidophilic microorganism that grows well in the acidic range of pH 2 to 5, or an acid-resistant microorganism that can grow from acidic pH 2 to about neutral. For example, bacteria such as Bacillus genus, Pseudomonas genus, actinomyces genus, Streptomyces genus actinomycetes, Saccharomyces genus, Hansenula genus, Candida genus yeast, and Aspergillus genus, Penicillium genus, Mucor genus fungi, etc. The existence of microorganisms with good acid resistance is known. In addition, the optimum pH of the enzyme (preferably protease) produced by the acid-resistant microorganism of the present invention is 2.0 to 4.0, preferably 3.0 to 4.0, more preferably 3.0 to 3.5. Such microorganisms are preferred.
[0008]
In the present invention, organic waste can be treated in an acidic region having a low pH by using such acid-resistant microorganisms. However, protein-assimilating microorganisms can be used as acid-resistant microorganisms. Particularly preferred. When this protein assimilating microorganism is used, the decomposition of the organic matter is performed, and at the same time, the pH of the acidified organic waste can be raised by the generation of ammonia by the decomposition of the protein. This is particularly preferable because neutral or weak alkaline environmental conditions in which many aerobic fermentations are actively performed can be adjusted. Such acid-resistant protein-assimilating microorganisms exist in the χ-Proteobacteria genus, Burkholderia genus, Bacillus genus, Xanthomonas genus, Pseudomonas genus and the like. The most preferred strains of these are respectively χ-Proteobacteria sp. MB8 (deposit number FERM P-16948) and Burkholderia sp. MB11 (deposit number FERM P-16949). And deposited at the Institute of Biotechnology, National Institute of Technology.
[0009]
In addition, the degradation accelerator or degradation method of the present invention does not exclude the addition of other microorganisms involved in the aerobic fermentation treatment. Many of these microorganisms have an optimum pH for growth from neutral to weakly alkaline, and the pH is shifted from acidic to neutral due to the effect of the degradation accelerator of the present invention, and its activity is restored and active. Decomposition reaction begins. Examples of microorganisms that can be used in combination include mesophilic and thermophilic microorganism preparations such as Bacillus.
The organic waste subject to the decomposition treatment of the present invention is not particularly limited as long as it is a waste decomposed by aerobic fermentation of microorganisms. For example, the waste other than kitchen waste discharged from kitchens. , Coffee lees, sake lees, sludge, and food residues discharged from food factories.
[0010]
There are no particular limitations on the timing and amount of use of the decomposition accelerator of the present invention. Generally, an appropriate amount may be quickly added when the pH of the fermented product is lowered for some reason. However, when protein-assimilable acid-resistant microorganisms are used, the pH of the fermentation-treated product can be lowered by allowing the degradation accelerator of the present invention to coexist with other microorganisms not having acid resistance from the start of the fermentation process. It is possible to prevent and make the fermentation process stable. In general, organic waste discharged from the food service industry is often weakly acidic. In addition, it has been difficult for organic wastes that exhibit acidity to be subjected to a smooth fermentation treatment unless they are neutralized. By adjusting the pH of the organic waste, the pH is quickly improved, and the fermentation in the subsequent fermentation treatment is promoted.
[0011]
Further, the decomposition accelerator of the present invention does not prevent the combined use with other compounds added to accelerate the decomposition of organic waste. The decomposition accelerator of the present invention can be used in combination with salts having a buffering action for maintaining the pH of organic waste from weakly acidic to weakly alkaline, substances on nitrogen-containing powders, and the like. For example, sodium phosphate salts, potassium phosphate salts, ammonium sulfate, urea and the like can be mentioned.
In the present invention, depending on the properties of the treated product (when the N source is insufficient), it is necessary to add the N source. Therefore, it may be necessary to add ammonium salt, urea, etc. added for the purpose of improving the C / N ratio of organic waste, but if possible, other organic waste rich in nitrogen sources Most preferably, they are processed in a mixed manner.
[0012]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples. In the following examples, parts and% are based on weight unless otherwise specified.
Example 1
First, microorganisms that can be preferably used in the present invention, χ-proteobacteria Esp-MB8 (deposit number FERM P-16948) and Burkholderia sp. MB11 (deposit number FERM P-16949) are used for protein degradation. Along with this, the effect of increasing the pH was demonstrated. The title strain is cultured for 5 days at 30 ° C. in an ACS medium (modified from Soil Biol. Biochem. 7, 345, 1975) with the following composition to grow the cell, pH of the medium, and proteolysis As an indicator, protease activity, a key enzyme acting in the first stage of the reaction, was measured.
[0013]
[Composition of ACS medium]
Starch: 1%, Casein: 0.3%, NaCl: 0.2%,
MgSO4 · 7H2O: 0.005%, CaCO3: 0.002%,
FeSO4 · 7H2O: 0.001%, KH2PO4: 0.3%,
The pH of the medium was 4.5.
[0014]
[Method for measuring growth of bacterial cells]
The growth of the bacterial cells was used as an indicator by measuring the adenosine triphosphate concentration (ATP concentration). The ATP concentration was measured using an ATP measurement reagent kit Lucifer LU (manufactured by Kikkoman Corporation) and based on luminescence measurement values measured by a luminometer (Lumitester K-100, manufactured by Kikkoman Corporation). The relative value was calculated.
[0015]
[Enzyme activity measurement method]
By the method of Murao et al. (J. Biol. Chem. 268, 349, 1993), the enzyme reaction was carried out under the conditions of pH: 3.0 and 37 ° C. using hemoglobin as a substrate. The amount of enzyme that produces 1 microgram of tyrosine-equivalent acid-soluble peptide per 1 ml of the reaction solution was defined as 1 unit (1 U).
[0016]
The changes over time in the growth of the bacterial cells, the protease activity secreted into the medium, and the pH value of the medium obtained by the above conditions and measurement method are shown in FIGS. According to the above results, it was found that protease was produced by the growth of the bacterial cells and the pH value of the medium was increased to near neutrality. A plot of the relationship between the protease activity in the medium and the pH value is shown in FIG. From this result, it was shown that the pH value was clearly shifted to the neutral side when protein degradation by the produced protease occurred.
[0017]
(Example 2)
Next, it verified about the decomposition reaction promotion effect by this invention using the waste actually discharged | emitted from the restaurant industry. The soot used here has a water content of 77.6%, a pH of 4.76, and a C / N ratio of 12.4, showing very general properties. After filling a 3-liter fermenter with 150 g (dry weight) of the reaction medium (Sugiogakuzu), which functions as a breathability improver and moisture adjuster, 200 g (wet weight) discharged from the canteen kitchen Two test sections were inoculated with either χ-proteobacterial Esp-MB8 strain or Burkholderia sp. MB11 strain, and fermentation treatment was carried out while stirring this with the medium. The initial moisture content in the fermenter was adjusted to 55%. After introducing the koji, air was vented from the bottom of the fermenter at a rate of 0.5 l / min. During the fermentation process, the temperature in the fermenter and the carbon dioxide concentration in the exhaust gas were continuously monitored to analyze the status of the fermentation process. Further, as a comparative example, a test area inoculated with Bacillus subtilis BN1001 (manufactured by Meiji Seika Co., Ltd., deposit number FERM P-11132) was similarly provided. This strain is a general species involved in the fermentation process of organic matter, but does not have acid resistance. This is referred to as Comparative Example 1.
[0018]
The changes over time in the concentration of carbon dioxide in the exhaust gas and the temperature in the fermenter during the fermentation process are shown in FIGS. In the test plots inoculated with χ-proteobacterial Esp-MB8 strain or Burkholderia sp. It can be seen that both the carbon concentration and the heat of decomposition show high values.
[0019]
【The invention's effect】
In the decomposition treatment of acidified organic waste such as garbage generated from kitchens, no special means is used by the decomposition accelerator of the present invention consisting of acid-resistant microorganisms, particularly acid-resistant protein-utilizing microorganisms. Can be efficiently decomposed. According to the present invention, not only is it active in an acidic state, but also the pH is automatically adjusted from neutral to alkaline due to protein degradation, the action of other microorganisms is activated, and efficient treatment is possible It becomes.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between culture time and ATP concentration for χ-proteobacterial Esp-MB8 strain and Burkholderia sp. MB11 strain.
FIG. 2 is a graph showing the relationship between culture time and protease activity for MB8 and MB11 strains.
FIG. 3 is a graph showing the relationship between culture time and pH for MB8 and MB11 strains.
FIG. 4 is a graph showing the relationship between medium pH and protease activity for MB8 and MB11 strains.
FIG. 5 is a graph showing the relationship between fermentation time and carbon dioxide concentration for MB8 strain, MB11 strain and Bacillus subtilis BN1001 strain.
FIG. 6 is a graph showing the relationship between fermentation time and fermenter temperature for MB8 strain, MB11 strain and Bacillus subtilis BN1001 strain.

Claims (3)

  Decomposition promotion of organic waste consisting of acid-resistant protein-assimilating microorganisms selected from χ-proteobacteria ESPI-MB8 (deposit number FERM P-16948) or Burkholderia sp. MB11 (deposit number FERM P-16949) The decomposition accelerator, wherein the organic waste is soot. An organic waste decomposition treatment method using the decomposition accelerator according to claim 1, wherein the organic waste is soot. A method for adjusting pH in a fermentation treatment process of organic waste, wherein the decomposition accelerator according to claim 1 is used, wherein the organic waste is soot.

Images