80results about How to "Improve acid production performance" patented technology

The invention relates to a lactobacillus plantarum strain having functions of effectively degrading nitrite and strongly producing acid and an application of the lactobacillus plantarum strain, and belongs to the technical field of bioengineering. The lactobacillus plantarum strain having the functions of effectively degrading nitrite and strongly producing acid is selected from conventional fermented pickled vegetables in Shenyang peasant families, wherein the strain is named FM-LP1-1, identified to be lactobacillus plantarum, and the strain is preserved in China General Microbiological Culture Collection Center with the preservation number of CGMCC No. 9488 on August 4, 2014. By taking FM-LP1-1 as a fermenting agent for fermenting vegetables, the content of nitrate in the fermented vegetable products is effectively reduced, the fermenting duration of the vegetables is shortened and the fermenting flavor of the vegetables is enhanced; and the strain disclosed by the invention is broad in application prospect.

The invention discloses a probiotics troche and a preparation method thereof. Functional leavening agents and germinated brown rice, Chinese herb medicine extract with anti-cold and hot irritability and a stabilizer capable of effectively enhancing the stability are added into a yoghourt fermenting process; poikilothermal yogurt fermentation enables proliferation of lactic acid bacteria to the maximum extent, so that the anti-cold and hot irritability of lactic acid bacteria is improved. yogurt and fruit and vegetable slurry are pre-treated by using a non-hot-working technology so as to prevent infectious microbe infection in the process, improve the juice yield of the fruit and vegetable slurry, increase the content of soluble cellulose of the fruit and vegetable slurry and prevent the fruit and vegetable slurry from brown stain. Moreover, when the fruit and vegetable slurry and the yogurt are mixed, a scientifically compounded freezing protecting agent which is relatively good in anti-freezing effect is added. Finally, the probiotics troche which is smooth in taste, uniform in texture, stable in state, natural in quality, high in viable count, strong in functionality and long in expiration data is prepared. The viable count is (1.75-2.55)x10<11> CFU / g. At normal temperature, the expiration data is 30-36 months.

The invention discloses a method for washing scales formed on tubes of a graphite heat exchanger. The method comprises the following steps: water washing for the first time (mechanical washing); pressure test for the first time; acid washing; water washing for the second time (mechanical washing); pressure test for the second time; alkali washing; water washing for the third time (mechanical washing); and pressure test for the third time. According to the method disclosed by the invention, the washing time is shortened and is generally about 3 days, the acid producing capacity of the graphite heat exchanger after the washing process can be increased from 86% to above 98%, and the method has no damage on the heat exchange tubes and can remarkably improve function recovery of graphite heat exchanger and the production capacity.

The invention pertains to the technical field of lactic acid preparation, and relates to a bacillus coagulans used to preparing L-lactic acid and application methods thereof. Pentose or hexose is taken as raw material, or agricultural and industrial wastes containing the pentose, the hexose or combinations thereof are taken as raw materials. Ferment is performed on the raw materials to obtain theL-lactic acid. By applying the method of the invention, the highest yield can reach 195g / L, optical purity is greater than 99%, the highest conversion rate of saccharic acid can reach 0.98, and throughput of the ferment process is 2.7g / L / h. By using the bacillus coagulans XZL4(DSM No.23183) and the bacillus coagulans XZL9(DSM No.23184) provided in the invention, high concentration of L-lactic acid can be produced by directly fermenting various reducing sugar in by-products produced in xylitol productions. According to the invention, low cost is achieved, and production efficiency is improved at the same time. The bacillus coagulans and the methods are applicable to popularization and application in industrial productions.

The invention belongs to the technical field of biochemical engineering and particularly relates to a method for preparing medical grade valine through fermentation. The method comprises the followingsteps: fermenting, filtering and concentrating to prepare coarse valine; performing primary acid dissolution on the coarse valine by adopting hydrochloric acid, cooling, crystallizing and centrifuging to obtain the valine solid and mother solution; performing secondary acid dissolution on the valine solid with hydrochloric acid, cooling, crystallizing and centrifuging to obtain the valine solid and mother solution again; dissolving the obtained valine solids with water by adopting distilled water, performing ion exchange, discoloration, refined filtration and crystallization, so as to obtainthe medical grade valine. According to the method disclosed by the invention, the fermentation efficiency is high, heteroacid can be effectively removed, the product quality is greatly improved, and the medical grade standard is reached.

The invention discloses an alfalfa bundling and wrapping ensiling method, and belongs to the field of processing of silage. The method comprises the steps of rolling and cutting alfalfa with two sub-steps, spraying different additives with sub-steps and then bundling and wrapping. A good reproduction environment is created for the anaerobic fermentation of probiotics in an ensiling process, and the reproduction of other harmful bacteria is suppressed; the additives are high in acid productivity, so that the pH of feeds can be rapidly lowered to well store nutritional ingredients in the feeds, the quality of the feeds can also be improved, the livestock disease resistance enhancement capability of the feeds can be improved, and healthy growth of livestock can be promoted; the method is high in mechanization and automation degree, easy to operate and high in speed and efficiency, the influence of weather is slight, and the feeds are convenient to transport and apply.

The invention discloses a method for producing citric acid by fermentation of mixed raw materials. The method comprises the following main steps of: performing crushing, size mixing, spraying liquefaction and filtration on corn and cassava respectively, then mixing two parts of filtrate according to a proportion and fermenting the mixture, and finally extracting the citric acid. The method effectively avoids cost rise caused by the fluctuation of single raw material, meanwhile enriches the nutrient components of fermented liquor, is favorable for improving the acid producing capability of citric acid fermentation strains, enables an enterprise to have great choice on the raw materials, and reduces the production cost. Moreover, compared with a method for producing the citric acid by the single raw material, the method has the advantages that: the fermentation liquor has good liquidity, the fermentation period is obviously shortened, and the fermentation index is higher.

The invention provides an escherichia coli genetically engineered bacterium for the synchronous high yield of L-tryptophan and L-valine, and application thereof. The genetically engineered bacterium is obtained through the steps that on a genome of escherichia coli, trpE (S40F) mutation is introduced while a promoter of tryptophan operon is replaced with a Ptrc promoter; an aroG (S180F) gene controlled by the Ptrc promoter is integrated to a tyrR locus; a serA (H344A, N364A) gene controlled by a Plac promoter is integrated to a yjiV pseudo gene locus; a glnA gene controlled by the Plac promoter is integrated to a ycjV pseudo gene locus; and then a bacillus subtilis alsS gene controlled by the Ptrc promoter is integrated to a yghx pseudo gene locus. Shaking flask fermentation is conducted through a strain to be able to accumulate the L-tryptophan within 22-28 h to 10-14 g / L, meanwhile the accumulation amount of valine reaches 5-7 g / L, and the total acid-producing ability is improved by50% or so compared with that of a tryptophan producing strain; and meanwhile, strain OD600 is different slightly, growth problems are avoided, but the acid-producing ability per strain is obviously improved by 120%, and effective utilization of carbon sources and cells is improved greatly.

The invention discloses a high-dietary-fiber bran and red jujube probiotics chewing tablet. The chewing tablet is prepared by pelleting, low-temperature drying, size stabilizing and tabletting of bran and red jujube fermented grain powder, a flavoring agent, a coagulator and a lubricant, wheat bran powder rich in dietary fiber and red jujube mud with full function and high sugar content are taken as raw materials, lactobacillus plantarum and leuconostoc mesenteroides subjected to domestication expanding culture are taken as leavening agents, and the chewing tablet is made through solid state fermentation, vacuum freeze drying and high-speed crushing. The high-dietary-fiber bran and red jujube probiotics chewing tablet has the advantages of easy obtain of the materials, low cost, few addition of supplementary materials, palatable flavor, high dietary fiber content and rich nutrient and intestinal probiotics of the lactobacillus plantarum and leuconostoc mesenteroides, and combined colony count is maintained at 8X107cfu / g above level within the product warranty period; the chewing tablet having good conditioning and healthcare functions on human constipation is a good healthcare food and can be chewed and eaten directly.

The invention discloses a microbial additive for alfalfa haylage, a preparation method and an application thereof. The additive is prepared from a bacterial suspension of aspergillusoryzae and an MRS liquid nutrient medium for streptococcus lactis according to the ratio of 50-70%: 50-30% in weight percent, wherein per milliliter of the bacterial suspension of the aspergillusoryzae at least contains 1.0*108 aspergillusoryzae spores, and per milliliter of the MRS liquid nutrient medium at least contains 4.0*108 cfu streptococcus lactis. The microbial additive quickens the initial fermentation rate of lactobacillus, enhances acid production capability, effectively inhibits the activity of saccharomycetes and other undesirable microorganism, strengths haylage effect and effectively promotes the production performance of cows, beef cattle, mutton sheep and swine. The strain adopted by the invention can be obtained easily, can be produced massively on application and has practicability.

The invention relates to a lactic acid producing strain and a method for producing lactic acid through the lactic acid producing strain. When the lactic acid is produced through the lactic acid producing strain namely pediococcus acidilactici Pa-COT, the lactic acid production speed is significantly increased, namely that the lactic acid producing strain Pa-COT can significantly increase the lactic acid production property during lactic acid production. Accordingly, when the lactic acid is produced through fermentation of the lactic acid producing strain Pa-COT, the production of the lactic acid can be greatly improved. Besides, the lactic acid producing strain Pa-COT further has the advantages of being low in fermentation cost and environmental-friendly. In addition, the lactic acid producing strain Pa-COT disclosed by the invention further has the following advantages that the lactic acid can be produced through normal fermentation at the fermentation temperature of 45-50 DEG C, thelactic acid producing strain has very good adaptability to a lignocellulose system and can bear stayers generated in the high-concentration preprocessing process, and lactic acid fermentation can be performed by using lignocellulose as a raw material.

The invention discloses a yoghourt slice and a preparation method thereof. In the fermentation process of yoghourt, a functional fermentation agent, functional sprouted cargo rice, Chinese herb extracts with cold and hot sensitivity resistance, and a stabilizing agent capable of effectively improving stability are added; the yoghourt is fermented under dynamic temperatures, so that the proliferation of lactic acid bacteria is maximized, and the cold and hot sensitivity resistance of the lactic acid bacteria is improved; a non-hot processing technique is adopted for pretreating the yoghourt and the pulp of fruits and vegetables so as to prevent microbial contamination during the process, increase the juice yield of the pulp of the fruits and the vegetables, increase the content of soluble cellulose in the pump of the fruits and the vegetables, and prevent the pulp of the fruits and the vegetables from generating brown stains; a refrigerating protective agent which is scientifically compounded and has a better refrigerating resistant effect is added while mixing the pulp of the fruits and the vegetables as well as the yoghourt. Finally, the prepared yoghourt slice is fine and smooth in mouth feel, homogeneous in texture, stable in state, natural in quality, high in viable count, high in functionality, and long in quality guarantee period, and the viable count is 1.75 *1011-2.55 *1011CFU / g. Under the normal atmospheric temperature, the quality guarantee period of the yoghourt slice is 30-36 months.

The invention relates to a method for preparing a recombinant L-glutamic acid producing strain with the high acid-producing property, the recombinant L-glutamic acid-producing strain prepared by the method and a method of producing L-glutamic acid through the recombinant L-glutamic acid producing strain in a fermentation manner. In the recombinant L-glutamic acid-producing strain prepared by the method, the expression level of an lpdA gene and an optional odhA gene and / or sucB gene is reduced by at least 10% relative to the wild type strain. Compared with the wild type strain, the acid producing concentration and the glucose-glutamic acid conversion rate of the recombinant L-glutamic acid producing strain in the L-glutamic acid production both are increased remarkably, that is, the recombinant L-glutamic acid-producing strain has the remarkably-improved acid production property for producing the L-glutamic acid; and the L-glutamic acid is produced through the recombinant L-glutamic acid in the fermentation manner, and the yield of the L-glutamic acid can be increased greatly.

The invention discloses female vaginal dominant bacteria lactobacillus gasseri H87 and application thereof in preparing a premature delivery preventing medicine, and belongs to the technical field ofmedical microorganisms. The L.gasseri H87 is a novel bacterial genus of a lactobacillus gasseri genus separated from a human body, a repelling effect is avoided, specifically, antibacterial peptide gassericin of the L.gasseri H87 maintains balance of a vaginal flora, and has higher capability of adhering to vaginal epithelial cells, the risk of inflammation of a urogenital region of a patient is reduced, meanwhile, the risk of pregnancy complications of a pregnant woman is reduced, and the strain can be stored for a long term, so that production is facilitated. Lactobacillus gasseri deficiencycan cause a bad pregnancy outcome, such as premature delivery, for the pregnant woman, and a female vaginal microenvironment is reshaped, and therefore the strain can well meet the actual clinical application requirements, and a novel idea is provided for reducing the premature birth rate.

The invention relates to a sourdough bread composite fermentation agent. Raw-material components and proportions of the sourdough bread composite fermentation agent are as follows: the raw-material components are fermentation strains lactobacillus curvatus, lactobacillus brevis and saccharomycetes and a freeze-drying protecting agent; a thallus quantity ratio of the fermentation strains lactobacillus curvatus, lactobacillus brevis and saccharomycetes is (1 to 5) to 1 to (1 to 10); and a weight ratio of mixed bacterial sludge of the lactobacillus curvatus and the lactobacillus brevis to the freeze-drying protecting agent is 1 to (1 to 9). According to the sourdough bread composite fermentation agent provided by the invention, a strain is separated from conventional sourdough starter; a natural bacterium mixing system of a conventional fermentation agent is simulated; the sourdough bread composite fermentation agent is prepared by combining fermentation culture, refrigerated centrifugation and vacuum freeze drying techniques; unique and abundant conventional flavor can be given to bread and the defect of insufficient fermentation flavor of an existing fermentation agent is overcome;meanwhile, a one-time fermentation method is adopted in preparing the bread by the fermentation agent provided by the invention; a making method is simple; characteristic flavor and mouth feel can begiven to the bread; the nutrient value is improved; and the shelf life is prolonged.

The invention discloses a culture medium and fermentation method capable of improving yield of corynebacterium glutamicum ectoines, and belongs to the field of bioengineering. The invention provides aformula of a fermentation culture medium. The fermentation culture medium is rich in a carbon source, a nitrogen source, inorganic salt and compound trace elements, which are required for growth of corynebacterium glutamicum CG-ECT3; a strain is enabled to rapidly grow, reproduce and be cultured for 13 hours; OD600 can reach over 40; a plasmid copy number is increased; and time of a lag period and time of a logarithmic phase are shortened. Meanwhile, according to the invention, by controlling residual sugar and a precusor substance L-asparaginic acid in fermentation liquor to be replenished in the fermenting process, the acid-producing ability of the recombinant corynebacterium glutamicum CG-ECT3 is improved, a fermentation period is shortened, and after fermentation is carried out for 45h, yield of the ectoines can reach over 48g / L.

The invention belongs to the technical field of fermentation and in particular discloses a process for preparing and extracting L-glutamine. The process comprises the following steps: preparing L-glutamine feed liquid, performing ultrafiltration treatment, removing mycoprotein and other macromolecular substances, performing activated carbon decolorization, strongly acidic cation exchange, vacuum concentration, isoelectric point cooling crystallization, centrifugation and the like on ultrafiltrate so as to obtain a crude product; re-dissolving the crude product, and sequentially performing weakly acidic and weakly alkaline ion exchange resin impurity removal, vacuum concentration, isoelectric point cooling crystallization, centrifugation and drying, thereby obtaining the refined L-glutamine. According to the process in the invention, the fermentation efficiency of the L-glutamine is improved, the finished product has high purity and total yield, the process is simple and convenient in production technology, the usage amount of the exchange resin is obviously decreased, and the amount of acid and alkali is greatly reduced, so that wastewater discharge is reduced, and environmental protection is facilitated.

The invention belongs to the technical field of production of amino acid and discloses a fermentation technology of L-tryptophan. The fermentation technology comprises the following steps: step one, preparing L-tryptophan fermented liquid; step two, carrying out secondary treatment on strains; step three, combining and extracting the L-tryptophan. According to the fermentation technology of the L-tryptophan, disclosed by the invention, the fermentation efficiency of the L-tryptophan is improved by treating the strains.

The invention belongs to the technical field of amino acid production and discloses a method for producing L-tryptophan by fermentation. The method comprises the following steps: an escherichia coli seed solution for producing L-tryptophan is inoculated to a fermentation medium with the inoculum size being 10%, culture temperature is 36.8-37.0 DEG C, dissolved oxygen amount is 20%, and pH in a tank is kept in the range of 7.0-7.2 by fed-batch of ammonium hydroxide; when fermentation is performed for 24 h, a nutrient solution is added to the tank in a fed-batch manner, sugar concentration in the tank is kept to be 0.5-1 g / L until fermentation is ended, the total fermentation time is 42-48 h, and L-tryptophan fermentation broth is obtained. The process is simple, and the fermentation efficiency and the glucose-to-acid conversion rate are high.

The invention discloses a method for purifying lactobacillus rhamnosus extracellular polysaccharides and relates to the extracellular polysaccharides. The method includes: inoculating a single colony on the MRS solid culture medium of seed conservation to the activated fermentation liquid cultured in the MRS liquid culture medium; adding CaCl2 with the final concentration being 10mM into the MRS liquid culture medium, using the activated fermentation liquid for inoculation to obtain inoculated fermentation liquid, and measuring the OD600 and pH values of 1ml of inoculated liquid which is cultured for 0, 2, 4, 6, 12 and 24 hours; removing the cells and protein of the inoculated fermentation liquid, adding glacial acetic acid, placing into a refrigerator for one night, centrifuging, removing supernatant, performing freeze-drying on sediment, taking out, dialyzing, performing freeze-drying to obtain crude extracellular polysaccharides, dissolving into pure water, dissolving the extracellular polysaccharides sample after dialyzing and freeze-drying into distilled water to prepare a 20mg / mL solution, centrifuging, and performing ion column chromatography on supernatant to obtain the lactobacillus rhamnosus extracellular polysaccharides.

The invention belongs to the technical field of monosodium glutamate preparation, and discloses an environment-friendly process for preparing monosodium glutamate. The process includes the following steps: step (1) preparing a glutamic acid fermentation liquid; step (2) reusing strains; and step (3) preparing the monosodium glutamate. According to the method, the yield of the monosodium glutamateis improved by preforming acid regeneration on waste thalli.

The invention relates to the technical field of microbial engineering, and particularly relates to acetobacter aceti and application thereof. Wherein the bacillus aceticus is lactobacillus aceticus LHZ-ST001, wherein a preservation unit is China General Microbiological Culture Collection Center (CGMCC for short), a preservation address is No.3, Yard 1, West Beichen Road, Chaoyang District, Beijing, a preservation date is September 10th, 2018, and a preservation number is CGMCC No.16448; the acetobacter aceti has high viable count in a fermentation culture medium, has strong acid and ethanol dehydrogenase producing capacity, has the capacity of being compounded with other lactic acid bacteria or saccharomycetes, has good tolerance to acid, and has the characteristic of high acid resistance.

The invention provides a culture medium for promoting synergistic proliferation of lactobacillus and bifidobacterium and application of the culture medium. The culture medium is prepared from the following components in percentage by mass: 2 to 5 percent of prebiotic composition, 0.5 to 5 percent of peptone, 0.5 to 2 percent of beef extract, 0.1 to 2 percent of yeast extract, 0.05 to 1 percent of diammonium hydrogen citrate, 0.05 to 1 percent of K2HPO4, 0.01 to 1 percent of MgSO4, 0.01 to 1 percent of MnSO4, 0.05 to 1 percent of tween-80 and 0.05 to 1 percent of L-cysteine hydrochloride. The prebiotic composition is prepared from stachyose, mannose oligomer and xylooligosaccharide according to the mass ratio of (1 to 2): (1 to 2): (0.1 to 1). The composite prebiotic culture medium can obviously improve the proliferation and acid production capacity of lactobacillus and bifidobacterium, and the activity and functions of common beneficial bacteria in the intestinal tract are ensured through high-density culture, so that the common beneficial bacteria can be effectively colonized in the intestinal tract.

The invention discloses a fruit paste troche containing lactic acid bacteria and a preparation method of the fruit paste troche. Functional leavening agents and germinated brown rice, Chinese herb medicine extract with anti-cold and hot irritability and a stabilizer capable of effectively enhancing the stability are added into a yoghourt fermenting process; poikilothermal yogurt fermentation enables proliferation of lactic acid bacteria to the maximum extent, so that the anti-cold and hot irritability of lactic acid bacteria is improved. Yogurt and fruit and vegetable slurry are pre-treated by using a non-hot-working technology so as to prevent infectious microbe infection in the process, improve the juice yield of the fruit paste, increase the content of soluble cellulose of the fruit paste and prevent the fruit paste from brown stain. Moreover, when the fruit paste and the yogurt are mixed, a scientifically compounded freezing protecting agent which is relatively good in anti-freezing effect is added. Finally, the fruit paste troche containing lactic acid bacteria, which is smooth in taste, uniform in texture, stable in state, natural in quality, high in viable count, strong in functionality and long in expiration data, is prepared. The viable count is (1.55-2.52)x10<11> CFU / g. At normal temperature, the expiration data is 30-36 months.

The present invention discloses a viable bacteria containing fruit pulp food and a preparation method thereof. Functional ferment, germinated brown rice, Chinese herb medicine extracts with cold and heat resistant irritability, and stabilizing agent which can effectively enhance the stability are added in the process of yogurt fermentation. A temperature variable yogurt fermentation technology can enable the proliferation of lactic acid bacteria to a maximum degree and improve the cold and heat resistant irritability of the lactic acid bacteria. Non-thermal processing technology is used to pretreat yogurt and fruit pulp to prevent infectious microbe infection during process, increase fruit juice yield rate, increase the content of soluble cellulose in the fruit pulp, and prevent browning of the fruit pulp. A scientifically compounded cryoprotectant with a relative good anti-freeze effect is added when the fruit pulp and yogurt are mixed. Finally the fruit pulp food with delicate mouthfeel, uniform texture, steady state, high number of viable bacteria, strong function, and long shelf life is obtained. The viable bacterium content is 1.55 * 10^11-2.52 * 10^11 CFU / g and the fruit pulp food can be stored for a shelf life of 30-36 months at room temperature.

The invention provides a circulating and mixing device in a two-phase anaerobic digester for efficiently promoting acid production. The circulating and mixing device comprises a generated acid digester and a generated methane digester, which are connected with each other through a circulating water pipeline, wherein a generated acid feeding system and at least one group of generated acid circulating systems are arranged on the generated acid digester; the generated acid feeding system comprises a generated acid feeding pump and at least one-stage generated acid feeding pipeline, wherein the generated acid feeding pump is connected with the generated acid feeding pipeline; and the generated acid feeding pipeline enters the generated acid digester. The multi-stage feeding system of the circulating and mixing device in the two-phase anaerobic digester for efficiently promoting acid production can increase contact time between acid-generating phase microorganisms and materials, improves acid-generating performance, and improves material degradation efficiency.

The invention relates to space-induced efficient bifidobacterium longum, an application thereof, and a preparation method of a capsule preparation thereof, wherein bifidobacterium longum is a strict anaerobion, and the live bacterium preparation of bifidobacterium longum is difficult to produce, and is easily inactivated during preservation and oral administration because live bacteria are sensitive to acid, alkali and heat. The invention provides bifidobacterium longum S7-T6, which is capable of being applied to preparation of medicines and healthcare products for regulating intestinal flora balance and treating diarrhea. The bifidobacterium longum disclosed by the invention has enhanced oxygen-resistant characteristic and salt-resistant characteristic, and can be stably inherited to 30 generations without degeneration and is capable of growing on a culture condition of NaCl content is 6%; results of methyl red experiments and VP (Voges-Proskauer) experiments are positive, which indicates that the acid production capacity of bifidobacterium longum is improved; and through clinical verifications, the live bacterium preparation of bifidobacterium longum is capable of promoting digestion, effectively regulating intestinal flora balance and can be used for preparing healthcare products or medicines.

The invention belongs to the technical field of fermentation and discloses a green production method of L-tryptophan by using thallus protease hydrolysate instead of yeast powder. The L-tryptophan canbe produced by steps as follows, separating the thallus from the fermentation broth, using trypsin for enzymatic hydrolysis after pretreatment, taking the thallus protease hydrolysate as preparationof fermentation medium by organic nitrogen sources during the fermentation process and the L-tryptophan is produced after ferment. The method improves the growth speed of the thallus and the speed ofresidual bacterial protein titer, lower the process cost sharply and has high practical value in industry.

The invention discloses a preparation method and application of cheese rich in gamma-aminobutyric acid (GABA), belonging to the technical field of food processing. The method provided by the invention comprises the steps of respectively activating a main leavening agent and an auxiliary leavening agent, adding sodium glutamate and pyridoxal phosphate into raw milk, sterilizing, then cooling, adding the main leavening agent and the auxiliary leavening agent, carrying out constant-temperature leavening, adding CaCl2, then carrying out constant-temperature leavening again, adding chymosin for curding, then cutting, standing at room temperature, heating, stirring for clotting, carrying out heat-preservation stirring, adding salt, and carrying out ripening processing, wherein the auxiliary leavening agent is freeze-dried bacterial powder of Lb. plantarum NDC 75017. Through the method, the cheese rich in GABA can be prepared, the yield of GABA in the cheese reaches up to 108.34mg / 100g, the addition of Lb. plantarum NDC 75017 cannot influence the physicochemical indexes, the microbiological indicators and the sensory characteristics of the cheese, meanwhile, the total content of free amino acid is obviously increased, the taste and the smell of the cheese can be improved, and the sensory evaluation of the cheese is obviously higher than that of a blank reference group.

The invention discloses a microbial strain mutation inducing method, clostridium butyricum strains and application of the clostridium butyricum strains. Through mutation induction of ultraviolet radiation and sodium nitrite, bacterial strains with significantly increased acid production are screened. The obtained bacterial strains can be utilized to produce acid substances such as butyric acid byfermentation. In addition, the strains can also be utilized for poultry breeding to improve the quality of poultry eggs, and can also be utilized for development and utilization of yogurt fermentation, chewable tablets and the like.