JPS589674B2 - caprolactam - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to Bacillus having the ability to assimilate cabrolactam (
The present invention relates to a method for decomposing and removing cabrolaccum, or decomposing and removing cabrolaccum and obtaining microorganisms using bacteria of the genus Bacillus.

Cabrolactum is a raw material for producing 6-nylon, and in the process Q of polycondensing cabrolactam to obtain 6-nylon, a chemical equilibrium is established that depends on the temperature when cabrolactam is polycondensed, so unreacted cabrolactam is etc. are present in the reaction system.

Therefore, in order to remove these unreacted substances, the polycondensate is formed into flakes or chips, and then purified using Method Q, such as extraction with a solvent such as water.

The low polycondensate removed in this way is an aqueous solution,
Most of the organic substances contained are unreacted cabrolactam, but the concentration of cabrolactam is usually kept at 2 to 3% in consideration of extraction efficiency, and a large amount of dilute aqueous cabrolactam solution is produced as a by-product in the nylon polymerization process.

From an economic and environmental standpoint, this aqueous solution is sent to a recovery process to recover cabrolactam through vacuum concentration, adsorption, etc. However, as mentioned above, the concentration is dilute, so the thermal energy required for vacuum concentration is is enormous and is not preferable from the point of view of energy conservation.

In addition, in adsorption, etc., the regeneration process of the adsorbent is complicated, and there are drawbacks such as complete adsorption.

In view of these circumstances, the present inventors focused on the occurrence of slime-like microorganisms in the flow path of aqueous cabrolactam solutions, and decomposed and removed cabrolactam by biological means, or decomposed and removed cabrolactam. In order to produce protein-rich microbial cells, we conducted a wide range of natural screenings using the agar plate method to find microorganisms capable of assimilating cabrolactam, and found that they belonged to the genus Bacillus from sewage sludge in Ujitonouchi, Uji City, Kyoto Prefecture. The present invention was completed by discovering a new bacterial strain that is thought to be able to quickly assimilate cabrolactam and providing protein-rich bacterial cells at a high yield.

That is, the present invention decomposes and removes cabrolactam by aerobically cultivating a microorganism that belongs to the genus Bacillus and has the ability to assimilate cabrolactam in a medium containing cabrolactam as a carbon source. , a method for removing cabrolactam characterized by obtaining microorganisms.

The bacterial strains used in the present invention belong to the genus Bacillus,
Any material can be used as long as it has the ability to assimilate cabrolactam.

A specific example of a preferred bacterial strain is, for example, Bacillus pumilu, which the present inventors isolated from sewage sludge in Ujitonouchi, Uji City, by a plate dilution method on an agar medium with cabrolactam as the sole carbon source.
s) 10 plants are listed.

The mycological properties of this strain are as follows.

(1) Cell morphology (cultured on broth agar medium, 37°C, 18 hours.

) Cell shape and size; rod-shaped, present singly.

(0.5-0.9μ) Formation.

The sporangium does not swell clearly.

Durham staining; positive acid-fast; negative (2) Growth status in each medium (cultured at 37°C for 1 to 3 days.

) Broth agar plate; Colonies are round, flat to lightly ridged, and the surface is moist and shiny.

Colorless to light brown.

Meat juice agar slant medium; Shows thread-like to spread-like agar.

Meat juice liquid medium: uniformly cloudy and does not form a bacterial film.

Meat juice gelatin puncture culture; grows well and liquefies gelatin.

Litmus milk: peptonizes milk, making it weakly alkaline.

G) Recose gravy agar slope; Grows as well as gravy agar slope.

Potato medium: Grows well and turns potatoes black.

Soybean agar slope: Grows better than gravy agar slope.

(3) Physiological properties (culture at 37°C for 1 to 3 days.

) Reduction of nitrate; ~ Denitrification reaction; ~ MR test; 10 VP test; + Production of indole; Production of hydrogen monosulfide: Hydrolysis of denfuso, which does not produce; Utilization of citric acid, which is not hydrolyzed; Making citric acid the only carbon Can be used as a source.

Use of inorganic nitrogen sources; use ammonium salts.

Pigment production: None Urease: + Catalase: + Growth range: PH4.5-9.5, temperature 10-45
Grows at °C.

Attitude towards oxygen; aerobic 0-F test; oxidative (glucose) Production of acids and gases from sugar; acids are produced from crucose, sucrose, and mannitol, but not from arabinose and xylose.

Gas is produced from any sugar Not done.

sodium chloride Tolerance: Meat juice liquid culture containing 7% salt Grows on the ground.

Vitamin requirement: Requires biotin.

Cabrolactam assimilation; caprolactam is the only carbon can be grown as a nitrogen source and a nitrogen source. Ru.

As mentioned above, this tooth strain is a spore-forming aerobic bacillus that is peritrichous and Durham-positive, and is catalase-positive, so it is included in Bergey's Manual of Determinative Bacteriology.
al of Determinative Bact-
According to the classification of Bacillus (Eriology) 7th edition, Bacillus (
It is considered to belong to the genus Bacillus.

In addition, the sporangium does not swell clearly, and the cell diameter is 0.9
μ or less, it grows better on glucose gravy agar slopes and soybean agar slants than on gravy agar slants, grows in 7% salt gravy liquid medium, and has no ability to hydrolyze starch and does not reduce nitrates. This strain, which differs in bioacidity from sugar in a few points, is Bacillus.
Pamirus (Baci-1 1us pum i lus)
) species and is considered to be a variety characterized by the ability to assimilate turniplactams, so it was named Bacillus pamilus No. 10 and deposited with the Institute of Microbial Technology, Agency of Industrial Science and Technology, Ministry of International Trade and Industry on November 1, 1971. .

The microorganism accession number is FIKEN Bacteria No. 2339 (F
ERM PA2 3 3 9).

The mycological properties were examined using the methods described in Culture Culture Theory (written by Sakazaki, Naya Shoten) and Experimental Agricultural Chemistry Volume 1 (edited by the Department of Agricultural Chemistry, Faculty of Agriculture, University of Tokyo, Asakura Shoten).

In order to decompose and remove cabrolactam in the present invention, or to decompose and remove cabrolactam and obtain microbial cells, for example, the above-mentioned strain is used, and cabrolactam is contained as a sole carbon source in an amount of 0.01 to 3% by weight. In aqueous solution, as inorganic salts, phosphate, iron salt, magnesium salt,
The culture may be performed in a medium to which potassium salts and the like are added, and ammonium salts, urea, natural organic nitrogen sources, etc. are added to supplement the nitrogen source.

It is also effective to add various vitamins, yeast extract, etc. as growth-promoting substances.

The culture conditions at this time include, for example, 10 to 45°C.
Preferably, the temperature is maintained at around 35° C., the pH is maintained in the range of 5 to 10, and the reaction is carried out aerobically for about 5 to 35 hours.

In this way, cabrolactam is completely decomposed and removed, and its residual concentration becomes about 10 ppm or less.

In addition, in order to obtain microbial cells from this culture solution, for example,
Centrifugation may be performed at 7,000 g for 5 to 10 minutes.

The bacteria obtained in this way contain spores, so they are highly resistant to heat, drought, and chemicals, and even if the quality of cabrolactam-containing wastewater is poor, once the bacteria are inoculated, The growth environment is improved, growth gradually occurs, and cabrolactam can be decomposed and removed.

In addition, if the bacterial cells obtained by centrifugation are dried, 60
A yellowish-brown powder containing more than 30% of protein is obtained, and this is industrially useful because it can be used as single-cell protein in feed, etc.

The present invention will be specifically explained below using Examples.

Example 1 Cabrolactam 1g, primary potassium phosphate 0.01g1
Potassium diphosphate 0.01g, ammonium sulfate 0.01g, yeast extract 0.001g. Ferrous sulfate 0.
001g, magnesium sulfate 0.001g in tap water 10
Dissolve in 0 ml, put in a 500 ml Erlenmeyer flask, and add 1
After sterilizing at 20°C for 15 minutes under 1 atm pressure, 10 Bacillus pumilus Arashi strains were cultured on an agar slant medium prepared by adding 2 g of agar to this medium
FER. MPA2 3 3 9) was inoculated and cultured with shaking at 35°C for 40 hours.

The thus obtained culture solution was centrifuged and the crude protein content was reduced to 60%.
% dry bacterial cells were obtained.

Further, the amount of residual cabrolactam in the supernatant was determined by gas clostography and was found to be 10 ppm or less.

Example 2 In the cabrolactam recovery step, cabrolactam-containing water called scouring water was diluted with tap water so that the cabrolactam concentration was 1%.

Add this (0.1% potassium phosphate, 0.1% potassium phosphate, 0.1% ammonium sulfate, 0.001% yeast extract, 0.001% magnesium sulfate, and adjust the pH to 7. After adjusting to 0, add 15 liters of the above-mentioned medium to the 30-liter fermenter ζ, sterilize it at 120°C under 1 atm pressure for 30 minutes, and preculture Bacillus paramis AIO strain (FERM PA2 3 3 9) in the same medium. was inoculated.

The cells were cultured at 35° C. for 34 hours, centrifuged to collect the cells, and dried, yielding 127.5 g of cells with a crude protein content of 62%.

In addition, the residual cabrolactam in the supernatant is less than io ppm, and the CODcr is approximately 800 ppm BOD5
was approximately 400 ppm.

Claims (1)

[Claims] 1. By culturing microorganisms belonging to the genus Bacillus and having the ability to assimilate cabrolactam aerobically in a medium containing cabrolactam as a carbon source, the cabrolactam can be decomposed and removed, or the microorganism can be decomposed and removed. A method for removing cabrolactam characterized by obtaining bacterial cells.