阅读说明：本技术 一种促进嗜蛋白产乙酸菌生成乙酸的方法 (Method for promoting protein-philic acetogenic bacteria to generate acetic acid ) 是由 冯雷雨 秦芷怡 李旭曜 段旭 陈银广 周琪 于 2019-09-12 设计创作，主要内容包括：一种促进嗜蛋白产乙酸菌生成乙酸的方法,在嗜蛋白产乙酸菌液中加入辅助材料,在光照条件下控制反应条件,提高以蛋白质为碳源的嗜蛋白产乙酸菌产乙酸量。所述辅助材料是能够在光照条件下产生活性物质促进微生物代谢的同时将CO<Sub>2</Sub>还原转化为乙酸的材料。所述辅助材料是性能优良且结构稳定的光催化半导体材料。所述光催化半导体材料可以是介孔状氮化碳或硫化镉纳米粒子。所述反应条件包括：所述辅助材料的浓度,运行的温度以及反应时间。本发明能有效提高嗜蛋白产乙酸菌生产乙酸量,降低化学合成乙酸对环境的污染,减少厌氧发酵中温室气体CO<Sub>2</Sub>的排放,对环境保护及资源化利用有很大的影响。本发明可应用于蛋白质废水及其它工业废水的处理。(A method for promoting the production of acetic acid by a protein-philic acetogenic bacterium is characterized in that an auxiliary material is added into a protein-philic acetogenic bacterium liquid, the reaction condition is controlled under the illumination condition, and the acetic acid production amount of the protein-philic acetogenic bacterium taking protein as a carbon source is increased. The auxiliary material can generate active substances under the condition of illumination to promote the metabolism of microorganisms and simultaneously convert CO 2 Reducing the material converted to acetic acid. The auxiliary material is a photocatalytic semiconductor material with excellent performance and stable structure. The photocatalytic semiconductor material can be mesoporous carbon nitride or cadmium sulfide nanoparticles. The reaction conditions include: the concentration of the auxiliary material, the temperature of operation and the reaction time. The invention can effectively improve the acetic acid production amount of the protein-philic acetogenic bacteria, reduce the environmental pollution caused by chemically synthesized acetic acid and reduce the greenhouse gas C in anaerobic fermentationO 2 The emission of the catalyst has great influence on environmental protection and resource utilization. The invention can be applied to the treatment of protein wastewater and other industrial wastewater.)

1. A method for promoting a protein-philic acetogenic bacterium to generate acetic acid is characterized in that: auxiliary materials are added into the liquid of the proteophilic acetogenic bacteria, the reaction condition is controlled under the illumination condition, and the quantity of the acetic acid produced by the proteophilic acetogenic bacteria taking protein as a carbon source is increased.

2. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria according to claim 1, wherein the method comprises the following steps:

the auxiliary material can generate active substances under the condition of illumination to promote the metabolism of microorganisms and simultaneously convert CO₂Reducing the material converted to acetic acid.

3. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria according to claim 1, wherein the method comprises the following steps: the auxiliary material is a conductor or semiconductor material with excellent performance and stable structure; preferably, the auxiliary material can absorb visible light and ultraviolet light with the wavelength of more than 200 nm.

4. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria as claimed in claim 3, wherein: the semiconductor material comprises mesoporous carbon nitride or cadmium sulfide nanoparticles.

5. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria according to claim 1, wherein the method comprises the following steps: the light source of the illumination is ultraviolet light or visible light.

6. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria according to claim 1, wherein the method comprises the following steps: the reaction conditions include: the concentration of the auxiliary material, the temperature of operation and the reaction time.

7. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria as claimed in claim 6, wherein: the reaction conditions include: the concentration of the auxiliary additive material is 10-500 mg/L, preferably 50-500 mg/L.

8. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria as claimed in claim 6, wherein: the operation temperature is 10-55 ℃, and preferably 20-35 ℃.

9. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria as claimed in claim 6, wherein: the reaction time is 24-72 h, preferably 48-64 h.

10. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria according to claim 1, wherein the method comprises the following steps: the method comprises the following steps:

(1) preparing a culture medium for the proteophilic acetogenic bacteria, preparing an acetogenic bacteria suspension and subpackaging;

(2) adding auxiliary materials into the acetogenic bacteria suspension liquid obtained in the step (1), uniformly mixing, filling nitrogen to expel oxygen, then placing the sealed reactor into a photoreactor, controlling the anaerobic fermentation temperature under the illumination condition, converting protein into acetic acid by utilizing the combined action of the materials and the proteophilic acetogenic bacteria, and completing the process of promoting the acetogenic bacteria to carry out anaerobic fermentation to produce acid by using the auxiliary materials.

11. The method for promoting the production of acetic acid by acetophilic acetogenic bacteria according to claim 10, wherein: in the step (1), the bacterial liquid is cultured to OD₆₀₀Greater than 0.8; and/or the presence of a gas in the gas,

in the step (2), the adding material is cadmium sulfide or carbon nitride; and/or the light source is ultraviolet light or visible light; the illumination intensity is 120-250mw/cm²To (c) to (d); and/or the addition concentration range of the auxiliary material is 10-500 mg/L, and more preferably 50-500 mg/L; and/or the mixing rotating speed of the illumination reactor is 60-150 rpm/min, and more preferably 80-120 rpm/min; and/or the anaerobic acid production reaction temperature in the illumination reactor is 10-55 ℃, and the preferable temperature is 20-35 ℃; and/or, said step (3)In the process, the acid production time of the zymophilic acetogenic bacteria in the anaerobic fermentation is 24-72 h, and the preferable time is 48-64 h.

12. Use of the method of any one of claims 1 to 11 for promoting the production of acetic acid by acetogenic proteinophils in the treatment of protein waste water and other industrial waste water.

Technical Field

The invention belongs to the technical field of environmental protection and resource utilization, and relates to a method for promoting the anaerobic fermentation of acetogenic proteophiles to produce acetic acid.

Background

Acetic acid (CH)₃COOH) is an important chemical raw material, is also a common flavoring agent and cleaning agent in life, has wide application and higher economic value. The traditional method for obtaining acetic acid is mainly chemical synthesis, namely acetic acid is synthesized by using organic matters through a chemical method, wherein 75% of acetic acid for industrial use is prepared by carbonylation of methanol, and often contains heavy metals, benzene substances and other impurities, the purity is low, and the synthesis process can cause burden to the environment. The other method for producing the acetic acid is that the acetic acid is generated by anaerobic fermentation of microorganisms (acetogenic bacteria), the anaerobic microorganisms convert complex organic matters into the acetic acid, and the generated acetic acid has high purity and strong environmental protection reliability. Therefore, the technology for producing acetic acid by anaerobic fermentation of acetogenic bacteria attracts extensive attention.

The anaerobic fermentation process of the complex organic matters mainly comprises 4 stages: (1) and (4) a hydrolysis stage. At this stage, the macromolecular organic substances in the fermentation liquor are decomposed into water-soluble simple organic substances under the action of hydrolase, such as carbohydrates to simple sugars, proteins to amino acids, and lipids to various lower fatty acids and glycerol; (2) and (4) an acidification stage. In the acidification stage, water-soluble hydrolysate simple micromolecule organic matters are converted into volatile fatty acid, alcohol, aldehyde, carbon dioxide and hydrogen; (3) and a hydrogen-producing and acetic acid-producing stage. At this stage, the acidification product (fatty acids such as propionic acid, butyric acid, valeric acid, alcohols, etc.) and hydrogen and CO₂Is converted into acetic acid by hydrogen-producing acetogenic bacteria; (4) a methanogenesis stage. At this stage, acetic acid, hydrogen, carbonic acid, formic acid and methanol are converted to methane, carbon dioxide and new cellular material. The production of acetic acid is closely related to the control of the first three stages, wherein the hydrolysis acidification stage has a slow speed and is considered as the rate-limiting stage of acid production by anaerobic fermentation, so that the hydrolysis rate of microorganisms to organic substances is accelerated by adding some substances or energy sources, and the acid production rate of the whole reaction can be effectively increased.

It is known toThe anaerobic fermentation process of the heteroorganics is also an exchange process of electrons and energy, and the conductive cilia and cytochrome of the microorganisms play a key role. In the process of organic matter anaerobic biological fermentation, if a certain substance can be added to replace the conductive cilia and the cytochrome of the microorganism to exchange electrons and energy, the efficiency of the organic matter anaerobic fermentation process is undoubtedly improved to a great extent. In addition, the photocatalysis also has certain influence on the production of acetic acid by anaerobic fermentation, and ultraviolet light or visible light is used as a light source, so that some semiconductor materials can be excited to produce active substances, and the metabolism of microorganisms is improved. However, there are few reports on studies on the use of cadmium sulfide or carbon nitride to promote the production of acetic acid by anaerobic fermentation of a proteophilic acetogen using a protein as a carbon source under light conditions. The technical difficulty is that the function of conductive cilia and cytochrome can be replaced in an organic matter anaerobic fermentation system, and CO can be stimulated to generate active substances under the condition of illumination to promote the metabolism of microorganisms and simultaneously promote the CO₂Reducing the material converted into acetic acid, thereby improving the fermentation effect of the microorganism. For example, when light is irradiated, cadmium sulfide nanoparticles are excited to release electrons and enter acetogenic bacteria to release CO₂Reducing the acetate into a common biosynthesis intermediate (acetyl coenzyme A) and finally converting the acetate into the acetic acid, thereby improving the yield of the acetic acid.

Disclosure of Invention

Aiming at the defects in the prior art, combined with recent laboratory findings, the invention aims to provide a method for improving the acetogenesis of acetogenic bacteria of the protein-philic type and reducing the greenhouse gas CO in anaerobic fermentation₂And (5) discharging.

In order to achieve the purpose, the invention adopts the following technical scheme:

the addition of the active substances into the acetogenic bacteria liquid has certain conductivity and good light absorption capacity, and can generate active substances under the illumination condition to promote the metabolism of microorganisms and simultaneously lead CO to be generated₂Auxiliary materials for reducing and converting into acetic acid, and conditions for producing acid after the materials are added are controlled, so that the acetic acid is generated by the acetophilic acetogenic bacteria.

A method for promoting the production of acetic acid by a protein-philic acetogenic bacterium is characterized in that an auxiliary material is added into a protein-philic acetogenic bacterium liquid, the reaction condition is controlled under the illumination condition, and the acetic acid production amount of the protein-philic acetogenic bacterium taking protein as a carbon source is increased.

Optionally, the auxiliary material is capable of producing active substances under illumination to promote microbial metabolism and simultaneously convert CO₂Reducing the material converted to acetic acid.

Optionally, the auxiliary material is a photocatalytic semiconductor material with excellent performance and stable structure.

Alternatively, the photocatalytic semiconductor material may be mesoporous carbon nitride or cadmium sulfide nanoparticles.

Optionally, the light source for the illumination is ultraviolet light or visible light.

The reaction conditions include: the concentration of the auxiliary material, the temperature of operation and the reaction time.

Optionally, the reaction conditions include: the concentration of the auxiliary additive material is 10-500 mg/L, preferably 50-500 mg/L.

Optionally, the operation temperature is 10-55 ℃, and preferably 20-35 ℃.

Optionally, the reaction time is 24-72 hours, preferably 48-64 hours.

Further, the method for promoting the production of acetic acid by the acetogenic proteinophilic bacteria comprises the following steps:

(1) preparing a culture medium for the proteophilic acetogenic bacteria, preparing an acetogenic bacteria suspension and subpackaging;

(2) adding auxiliary materials into the acetogenic bacteria suspension liquid obtained in the step (1), uniformly mixing, filling nitrogen to expel oxygen, then placing the sealed reactor into a photoreactor, controlling the anaerobic fermentation temperature under the illumination condition, converting protein into acetic acid by utilizing the combined action of the materials and the proteophilic acetogenic bacteria, and completing the process of promoting the acetogenic bacteria to carry out anaerobic fermentation to produce acid by using the auxiliary materials.

In the step (1), the bacterial liquid is cultured to OD₆₀₀Greater than 0.8;

in the step (2), the adding material is cadmium sulfide or carbon nitride; and/or the light source is ultraviolet light or visible lightA light; the illumination intensity is 120-250mw/cm²To (c) to (d); and/or the addition concentration range of the auxiliary material is 10-500 mg/L, and more preferably 50-500 mg/L; and/or the mixing rotating speed of the illumination reactor is 60-150 rpm/min, and more preferably 80-120 rpm/min; and/or the anaerobic acid production reaction temperature in the illumination reactor is 10-55 ℃, and the preferable temperature is 20-35 ℃; and/or in the step (3), the acid production time of the zymophilic acetogenic bacteria in the anaerobic fermentation is 24-72 hours, and the preferable time is 48-64 hours.

The method for promoting the production of acetic acid by the protein acetogenic bacteria is applied to the treatment of protein wastewater and other industrial wastewater.

The basic principle of utilizing the material to promote the anaerobic fermentation of the protein acetogenic bacteria to produce the acetic acid in the invention is as follows:

the materials involved in the invention are all conductors or semiconductors, have good light absorption capacity, such as the capability of absorbing visible light and ultraviolet light with the wavelength of more than 200nm, and can generate active substances under the illumination condition to promote the metabolism of microorganisms and simultaneously promote CO₂The photocatalyst semiconductor material is excellent in performance and stable in structure, and is converted into acetic acid through reduction, such as mesoporous carbon nitride and cadmium sulfide nanoparticles. Due to the addition of the material, the microorganism does not need the conductive cilia and the cytochrome to exchange electrons and energy among species any more, but is directly attached to the surface of the conductor material, and long-distance direct exchange of electrons and energy among species is realized by means of the higher conductivity and the larger specific surface area of the conductor material. Therefore, the addition of the material can improve the hydrolytic acidification efficiency of the microorganisms on the organic matters to a certain extent, and further improve the yield of acetic acid. In addition, when light irradiates, the photocatalytic semiconductor material is excited to release electrons, activate molecular oxygen, generate superoxide radical or hydroxyl radical to bombard CO₂And reducing it to acetic acid, thereby increasing acetic acid production. On the other hand, many life activities are accompanied by the generation, change or disappearance of free radicals, and the semiconductor photocatalytic material can also affect the physiological activities of microorganisms by generating the free radicals, improve the metabolism of the microorganisms and further improve the yield of acetic acid. In addition, carbonizedThe nitrogen or cadmium sulfide has certain promotion effect on the activity of microbial enzymes related to anaerobic fermentation. Some enzymes participating in anaerobic fermentation for producing acetic acid contain a small amount of transition metal ions (ions) such as iron, cobalt, manganese and the like, the active sites of the transition metal ions are often active centers of the enzymes, and the existence forms of the transition metal ions (ions) can be changed by adding nitrogen carbide or cadmium sulfide so as to enhance the activity of some enzymes, thereby increasing the production amount of the acetic acid.

In the process of promoting the anaerobic fermentation of the acetogenic bacteria of the protein-philic type to produce the acetic acid by using the material, the fermentation acid production condition needs to be well controlled in order to improve the yield and the economic benefit of the acetic acid. The reaction conditions mainly controlled in the invention comprise: the concentration of the added materials, the operating temperature and the reaction time of the acidogenic experiment of the acetogenic bacteria of the protein-like property. In the invention, the added materials can effectively promote the protein acetogenic bacteria to convert protein into acetic acid within the range of 10-500 mg/L, and the ideal material addition range adopted by the invention is 50-500 mg/L by comprehensively considering the relationship between the raw material cost and the cumulative yield of acetic acid. The operation temperature affects the hydrolysis efficiency of organic matters and the activity of microorganisms in the system, so that the accumulation of acetic acid is affected, and therefore, the experimental temperature control range is 10-55 ℃, and the ideal range is 20-35 ℃. In addition, the reaction time of the acid production experiment of the acetophilic protein-producing bacteria can also influence the accumulation of acetic acid, the yield of the acetic acid after the materials are added tends to increase first and then decrease along with the reaction time, the yield is increased maximally when the yield is 36h, and the activity of the acetophilic protein-producing bacteria is considered to be higher when the reaction time is less than 72h, so that the accumulation of the acetic acid is facilitated, therefore, the reaction time of the acid production experiment of the acetophilic protein-producing bacteria is 24-72 h, and the ideal reaction time is 48-64 h.

The advantages and the effect benefits generated by the practical application of the invention comprise:

1. acetic acid is an important chemical raw material and is widely applied, most industrial acetic acid is prepared by carbonylation of methanol, and often contains heavy metals, benzene substances and other impurities, and the synthesis process can cause burden to the environment, so that the technology for producing the acetic acid by developing and utilizing materials to improve the anaerobic fermentation of the proteophilic acetogenic bacteria has great economic value.

2. The concept of converting protein in the culture medium into acetic acid can be extended to be applied to actual protein wastewater treatment, protein wastewater and other industrial wastewater can be effectively converted into acetic acid with higher utilization value, the pollution damage effect of organic dirt in the wastewater on the environment is reduced, and the concept of circular economy is met.

3. The material and the light source can promote the activity of related enzymes in acid-producing microorganisms, improve the permeability of microbial cell membranes, influence the structures of biomacromolecules in cells and radicals participating in biological reaction, promote the decomposition and conversion of organic matters, further promote the acid-producing rate and yield of anaerobic fermentation of acetogenic bacteria, effectively shorten the time of fermentation acid production, reduce the volume of an acid-producing treatment system and reduce the operation cost.

Detailed Description

Aiming at the defects in the prior art, the invention provides a method for improving the acetic acid production of a proteophile acetogenic bacterium by combining recent laboratory findings, which comprises a method for promoting the proteophile acetogenic bacterium to carry out anaerobic fermentation to produce the acetic acid by utilizing cadmium sulfide or carbon nitride under the illumination condition. The method is characterized in that the electron transfer capacity is improved by using materials and light energy, the microbial activity is enhanced, and CO is simultaneously introduced₂Conversion to acetic acid, reduction of greenhouse gas CO in anaerobic fermentation₂Discharge, and has great promotion effect on environmental protection and resource utilization.

The present invention will be further described with reference to the following examples.