JPS6156087A - Production of organic acid by immobilized microorganism - Google Patents

Abstract

PURPOSE:To produce and recover a useful organic acid, in high efficiency, by treating waste water containing organic materials with immobilized microorganisms capable of producing the acid. CONSTITUTION:Microorganisms capable of producing an organic acid are included in a gelatinous carrier, and immobilized by conventional immobilization technique. The immobilized microorganisms are proliferated by cultivation, and made to contact with waste water containing organic materials. The cultivation and the contact of the immobilized microorganism with the organic-containing waste water is carried out at 20-45 deg.C and 4-6pH in the case of using a medium- temperature digestion sludge of sewage as the seed sludge, or at 45-60 deg.C and 4-6pH in the case of using a high-temperature digestion sludge. For example, the immobilized microorganisms and waste water are charged to a fermentation tank composed of the jacket 1, the fluidizing zone 2, and the settling zone 3, and the fermentation of the waste water is carried out. The fluidizing zone 2 is furnished with the device 4 to control and display the temperature and pH. The generated gas is separated by the gas-separator 5 and discharged from the reactor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for producing organic acids by treating organic substance-containing wastewater using immobilized microorganisms capable of producing acids. The present invention, of course, relates to a method that not only treats organic matter-containing wastewater, but also produces useful substances called organic acids, which can be recovered if necessary.

Prior Art J'3 and its Problems Conventionally, wastewater containing solids has been treated by an aerobic treatment method such as an activated sludge method, or by a general methane fermentation method.

However, in the former case, the dissolved oxygen in the aeration tank should be
The higher the BoO, the greater the aeration power required, and the sludge insects generated are also 0.5 to 0.7o (MLSS)/a (BOD).
There were many problems, and it was difficult to dispose of the excess sludge. On the other hand, in the latter case, the growth rate of methane-producing bacteria is slow, and if the residence time of wastewater in the tank is shortened, organic acids accumulate, which directly or indirectly reduces the pH 1, thereby increasing the growth of methane-producing bacteria. This resulted in the need for a retention period of 10 to 30 days. Therefore, this method is also not realistic as an energy production process, and its improvement is e:! ! It was rare.

In addition, all of these methods are primarily aimed at wastewater treatment or methane production, and are not designed to actively produce useful organic acids produced by fermentation.

The purpose of this invention is to solve all of the above-mentioned problems under these circumstances and to provide a method that can produce useful organic acids by treating wastewater containing substances. .

Means for Solving the Problems This invention provides an immobilized microorganism characterized by culturing and proliferating a microorganism having acid-producing ability immobilized on a carrier, and then bringing the immobilized microorganism into contact with an organic matter-containing whole. This is an acid production method.

When medium-temperature digested sludge from a sewage treatment plant is used as the seed sludge, culture of the immobilized microorganisms and contact of the immobilized microorganisms with the wastewater containing fertilized substances are carried out at a temperature of 20 to 45°C, preferably 35 to 35°C.
40°C, 11H4, 0-6.0 preferably 5.0-5
．． The test was carried out under the conditions of 5.

In addition, when using high-temperature digested sludge, the immobilized microorganisms
8. The contact between the nutrient and immobilized microorganisms and the wastewater containing stone dwarf is carried out at a temperature of 45 to 60°C, preferably 50 to 55°C, +)l-(4
,0 to 6.0, preferably 5.0 to 5.5.

Immobilization of microorganisms is carried out as follows by a known entrapping method in which microorganisms are wrapped in a gel-like carrier. That is, after warming a predetermined group of microbial cells in an aqueous solution of a gel base, this mixture is brought into contact with a cold gelling agent, and the resulting gel is heated to the desired size. Form into granules or films.

In addition, when polyacrylamide is used as a gel substrate, acrylamide monomer, an ITG agent, an m-merization accelerator, and a polymerization initiator are added to a solution containing a predetermined number of microbial cells, and the seven polymers are polymerized to produce a gel. is molded as described above. Carrageenan, sodium alginate, polyvinyl alcohol, polyacrylamide, polyurethane, etc. are used as the gel base, potassium chloride, calcium chloride, magnesium chloride, etc. are used as the gelling agent, and N is used as the crosslinking agent.

N--methylenebisacrylamide or the like is used, β-dimethylaminopropionitrile or the like is used as the combination accelerator, and potassium per(A-ate) or the like is used as the initiator.

Fermentation in which acid is produced by contacting immobilized microorganisms with waste water containing impregnated substances may be either batch fermentation or continuous fermentation. As the light tower, a stirred fermenter, a fixed bed fermenter (convex, a fluidized bed fermenter, etc.) are used.

Examples of wastewater containing organic matter include wastewater containing municipal waste, sewage sludge, sludge from valves, food processing wastewater such as alcohol distillation waste, and human waste.

Effects of the Invention According to the method for producing acidic acid of the present invention, microorganisms that have acid-producing ability are immobilized on a carrier, and the immobilized microorganisms are grown. As a result, the number of days that wastewater remains in the tank (81) can be significantly shortened, and by using immobilized microorganisms, excess sludge can be reduced. Thus, according to the present invention, useful organic acids can be efficiently produced by treating organic matter-containing wastewater.

EXAMPLES Next, examples of the present invention will be shown to illustrate the effects of the present invention.

Example 1 (1) Preparation of immobilized acid-producing bacteria
+1/1, dipotassium hydrogen phosphate 3g/I.

Potassium dihydrogen phosphate 2g//, ammonium carbonate 5
Q/1, sodium carbonate 3o/a, ferric chloride 6
Synthetic wastewater consisting of 19/l of water salt was prepared, and this was used as a culture medium. Medium-temperature digested sludge from a sewage treatment plant was acclimatized in this culture medium at a temperature of 37°C to a pH of 5.0 to 5.5, and the acclimatized sludge obtained was 100 RI/was concentrated to 20 m/bin. This thickened sludge was mixed with 180ml of a sterilized 2% carrageenan aqueous solution kept at a temperature of 40°C, and the mixed solution was dropped into 1.51ml of a 0.1M calcium chloride aqueous solution. In this way, a bead-like gel with a diameter of about 4 mm+ was formed which contained the acid-producing bacteria.

Then, the immobilized bacteria were incubated in a medium with the above composition at a temperature of 3.
The cells were cultured at 7° C. and pH 5.0 to 5.5 for 24 hours for proliferation.

(2) Production fermentation of 1111!2 (1!! and fluidized bed fermentation (a) with an actual volume of 11 as shown in the attached drawing was used. The same type has a small diameter fluidized section (2) with a jacket (1) and a large-diameter sedimentation section (3) for bacterial cell sedimentation called if! on top of this, and a temperature and p l-1 control display device (4) is provided in the flow section (2). A cylindrical gas separation member (5) for separating the generated gas from the y1 fermentation liquid is installed in the sedimentation section (3).

The organic matter-containing wastewater is then supplied to the bottom of the tank, and the treated wastewater is overflowed from the top of the tank. A portion of the waste water at the top of the tank is circulated to the bottom of the tank, and the content of the generated gas is measured using a wet gas meter 6).

The Mizonari fermenter was filled with the immobilized acid-producing bacteria and the synthetic wastewater, and fermentation was carried out for one day at a temperature of 37°C and a pH of 5.0 to 5.5. After that, the synthetic wastewater was continuously supplied, and the synthetic wastewater was continuously supplied. Fermentation was carried out. Then, by gradually increasing the amount of synthetic wastewater supplied, the organic matter load reached a maximum of 350 kg/l113-
Even at an 8i1 distillation time of 2.6 hours, organic acids could be produced at a temperature of about 13 days (1/1).

Example 2 (1) Preparation of immobilized acid-producing bacteria Medium-temperature digested sludge from sewage treatment was acclimatized with alcohol distillation waste liquid at a temperature of 37°C and pH 5.0 to 5.5, and the obtained acclimatized sludge 1001/1. It was reduced to 20all. This thickened sludge was mixed with 18Ql of a sterilized 4% carrageenan aqueous solution kept at 40°C, and the mixed liquid was
dropwise into a 2% aqueous potassium chloride solution. In this way, bead-shaped gels with a diameter of about 4 mm were formed that contained acid-producing bacteria.

Then, the fixed live bacteria were incubated at 1f1 in a medium with the above composition.
The cells were cultured at 37° C. and pH 5.0 to 5.5 for 24 hours for proliferation.

The alcohol distillation waste liquid is 280% molasses from the Philippines.
24 using a medium consisting of Q/l and 1.4 g// of urea.
Time-alcoholic fermentation (yeast accharomyces cerevisiae)
This is a waste liquid obtained by boiling the fermented liquid for about 4 hours to scatter the alcohol after carrying out the IAC IFOO224). The BOD of this waste liquid is 33000 II
It was 1 g/l.

(2) Production of 8N acid In a mechanically stirred fermenter with an actual volume of 21, the above-mentioned immobilized acid-producing bacteria and the above-mentioned alcoholic distillation waste liquid were put into a total volume of 11, and the pH was 5°0 to 5 at a temperature of 37°C with stirring. Fermentation was carried out for 24 hours at a temperature of .5. Next, continuous fermentation was carried out by continuously supplying the above alcohol distillation waste liquid, and the supply amount of the waste liquid was gradually increased. As a result, the BOD volume was increased to a maximum of 102 KO.
/II+3 ·day, and a specific acid could be produced at a temperature of approximately 100/1.

Example 3 (1) Preparation of immobilized acid-producing bacteria Using the synthetic wastewater shown in Example 1, high-temperature digested sludge from a sewage treatment plant was acclimatized at a temperature of 51°C to f) H5.0 to 5.5, The obtained acclimatized sludge 1001I was concentrated to 20+11
/ After binding, this thickened sludge is diluted with sterilized physiological saline (140 ml).
01/.

(Acrylamide monomer 1 was added to the acid-producing bacterial suspension.)
5 g and 0.89 g of N,N-methylenebisacrylamide were mixed, and 5% β-dimethylamine propionitrile 20+1/2 and 2.5% potassium persulfate 20+11/ were added to a colander. Next, the mixed solution was injected into four 10 cm x 10 cm vats, and left at a temperature of 25°C for 15 minutes.
.

This gel was shaped into a cube with a side of about 5 mm. In this way, acid-producing bacteria were immobilized.

Then, the obtained immobilized bacteria were cultured in the above synthetic wastewater at a temperature of 51° C. and a pH of 5,0 to 5.5 for 24 hours to perform proliferation.

(2) Mechanically stirred fermentation with a physiological actual volume of 2I of Aiho acid (Pour the above-mentioned immobilized acid-producing bacteria and the above-mentioned synthetic wastewater into a to make a total volume of 11, and under stirring at a temperature of 51°C 1) H5 , 24-hour batch production at 0-5°5 B
I did it. Next, continuous fermentation was carried out by continuously supplying the above synthetic wastewater, and the supply amount of the wastewater was gradually increased, resulting in a polyphonic dynamic load of up to 180 kg/m'・day.
It was possible to generate silicic acid at a temperature of about 9 g// with stable continuous operation.

Example 4 (1) Preparation of immobilized acid-producing bacteria High-temperature digestive bacteria from a sewage treatment plant were acclimatized with the alcohol distilled waste liquid described in Example 1 at a temperature of 51° C. and a pH of 5.0 to 5.5. Then, the obtained acclimatization power of 1100 m/
50g of urethane prepolymer kept at 0℃! @Add to the suspension and mix both well to obtain a polyurethane gel.
This gel was cut into cubes of approximately 511,111 sides. In this way, acid-producing bacteria were immobilized.

Then, the obtained fixed medium was incubated at a temperature of 51°C in a medium with the above composition.
The cells were cultured for 24 hours at pH 15.0 to 5.5 for proliferation.

(2) Production of elic acid A fixed bed type fermenter with an actual volume of 11 is filled with the above immobilized acid producing bacteria and the above alcohol distillation waste liquid, and the temperature is 5.
Batch fermentation was carried out at 1° C. and pH 5.0 to 5.5 for 24 hours. Next, continuous fermentation was carried out by continuously supplying the above-mentioned alcohol distillation waste liquid, and the supply m of the waste liquid was gradually increased. As a result, the BOD volume ram load reached a maximum of about 120 Ko/l11.
It was possible to increase the temperature up to 3 days, and produce aisoic acid at a temperature of about 99% in stable continuous operation.

[Brief explanation of drawings]

The drawing is a longitudinal cross-sectional view of the fluidized bed fermenter used in Example 1. (2)...Flowing part ζ (3)...Settling part, (5)...
...Gas separation member. 4 people other than above

Claims (6)

[Claims] (1) A method for producing organic acids using immobilized microorganisms, which comprises culturing and proliferating microorganisms immobilized on a carrier and capable of producing acids, and then bringing the immobilized microorganisms into contact with wastewater containing organic matter. (2) The method according to claim 1, wherein the operation is carried out at a temperature of 20 to 45°C and a pH of 4.0 to 6.0. (3) The method according to claim 2, wherein the operation is carried out at a temperature of 35 to 40°C and a pH of 5.0 to 5.5. (4) The method according to claim 1, wherein the operation is carried out at a temperature of 45 to 60°C and a pH of 4.0 to 6.0. (5) The method according to claim 4, wherein the operation is carried out at a temperature of 50 to 55°C and a pH of 5.0 to 5.5. (6) The method according to any one of claims 1 to 5, wherein the immobilization of microorganisms is carried out by an entrapment method.