39 results about "Acid stress" patented technology

The invention discloses an acid-stress-resisting component and belongs to the technical field of biological engineering. An rbsA gene obtained from lactococcus lactis (L.lactis NZ9000) is excessivelyexpressed in the lactococcus lactis (L.lactis NZ9000) to obtain recombinant lactococcus lactis (L.lactis NZ9000) (pNZ8148/RbsA) with the remarkably improved acid-stress-resisting capability. The survival rate of a recombinant strain is 5.8 times as much as that of a control group after the recombinant strain is stressed for 3h under the condition that the pH (Potential of Hydrogen) is 4.0. The invention further provides a method for improving the acid stress resistance; the method has good industrial application value.

The invention discloses acid stress resistant recombinant lactic acid bacteria and application thereof, and belongs to the field of bioengineering technology. By overexpression of TraG gene derived from L.lactis NZ9000 in L.lactis NZ9000, the recombinant L.lactis NZ9000 (pNZ8148/TraG) with acid stress resistance remarkably enhanced is obtained. By stress for 3 h at pH 4.0, survival rate of the recombinant strain is 61.3 times higher than survival rate of a contrast. The invention also provides a method for raising acid stress resistance. The method of the invention has good industrial application value.

The invention discloses an anti-acid-stress component and application thereof, belonging to the field of bioengineering technology. According to the invention, two recombinant Lactococcus lactis strains with substantially improved resistance to acid stress, i.e., L. lactis NZ9000 (pNZ8148/RecT-A76) and L. lactis NZ9000 (pNZ8148/RecT-MG1655), are obtained by overexpression of recT genes, originated from Lactococcus lactis L. lactis A76 and Escherichia coli E. coli MG1655, in Lactococcus lactis NZ9000, respectively. After the two recombinant Lactococcus lactis strains suffer from stress in an environment with a pH value of 4.0 for 3h, the survival rates of the two strains are 10.5 times and 1.4 times the survival rates of control strains, respectively; and after the two strains suffer from stress caused by 20% (v/v) ethanol for 6 h, the survival rates of the two strains are 3.7 times and 2.1 times the survival rates of control strains, respectively. The invention also provides a method for improving resistance to acid stress. The method has good industrial application value.

The invention discloses a co-cultivation method for improving the acid resistant ability of saccharomycetes, and belongs to the technical field of bioengineering. The co-cultivation method comprises the following steps: carrying out pre-culture on cultured lactic acid bacteria for 4 hours in a culture medium, then putting the saccharomycetes in the culture medium to carry out co-culture for 4 hours, re-suspending an obtained thallus in lactic acid-containing physiological saline (pH=1.9, 30 DEG C) and stressing for 90min, centrifugally washing the thallus subjected to acid stress, dibbling thethallus on a yeast extract peptone dextrose agar culture-medium (containing 0.01% of chloramphenicol), and carrying out stationary culture at the temperature of 30 DEG C for 48 hours. Compared with the saccharomycetes which are not co-cultured, the cell population of the saccharomycetes is increased by 7.16 times. The method is simple and convenient to operate and can be used for improving the stress resistance ability of the saccharomycetes.

The invention discloses acid stress resistant recombinant lactic acid bacteria and a construction method thereof, and belongs to the field of bioengineering technology. By overexpression of LtrC genederived from L.lactis NZ9000 in L.lactis NZ9000, the recombinant L.lactis NZ9000 (pNZ8148/LtrC) with acid stress resistance remarkably enhanced is obtained. By stress for 3 h at pH 4.0, survival rateof the recombinant strain is 3.6 times higher than survival rate of a contrast. The invention also provides a method for raising acid stress resistance. The method of the invention has good industrialapplication value.

The invention discloses acid-stress-resisting recombinant lactobacillus and belongs to the technical field of biological engineering. A GreAB gene obtained from lactococcus lactis (L.lactis NZ9000) isexcessively expressed in the lactococcus lactis (L.lactis NZ9000) to obtain recombinant lactococcus lactis (L.lactis NZ9000) (pNZ8148/GreAB) with the remarkably improved acid-stress-resisting capability. The survival rate of a recombinant strain is 10.4 times as much as that of a control group after the recombinant strain is stressed for 3h under the condition that the pH (Potential of Hydrogen)is 4.0. The invention further provides a method for improving the acid stress resistance; the method has good industrial application value.

The invention discloses a strain of lactobacillus fermentum KP101 and application thereof in preparing fermented yogurt and probiotic solid beverages. The preservation number of the lactobacillus fermentum KP101 is CCTCC No. 2019085. The lactobacillus fermentum KP101 has good acid stress resistance, cholate stress resistance and oxidative stress resistance, can resist pathogenic infection, regulate metabolic disturbance, regulate hyperlipidemia and the like, and also can reduce fat and reduce weight. Animal experiments show that the increase of TG and LDL-c in serum caused by high fat diet canbe effectively reduced by 50.5% and 67.0% respectively; the level of HDL-C in liver can be significantly improved by 78.9%; the contents of TC, TG and LDL-C in liver can be reduced by 36.2%, 64.6% and 42.8% respectively; a significant fat reducing effect is also achieved, and the perirenal fat reduction coefficient and the abdominal fat reduction coefficient are 97.2% and 95.5% respectively.

The invention relates to a method for improving the acid stress resistance of lactococcus lactis, which belongs to the technical field of bioengineering. The invention is a method for improving the acid stress resistance of the lactococcus lactis through exogenous addition of glutathione. The method mainly comprises the steps of addition of the exogenous glutathione and culture of the lactococcus lactis. By utilization of the whole set of the method, the target strain with acid resisting capability can be quickly obtained within 2 to 4 days. Exogenous addition of the glutathione effectively improves the survival rate of the lactococcus lactis under the condition of acid stress, and reduces the death rate of the lactococcus lactis during fermentation under the prior preserving condition and in an in vivo acid environment. Moreover, because the glutathione is safe and harmless to people and animals and has the function of health care, the concept can be used in the process of preparing a starter in the milk product industry.

The invention discloses a method for regulating acid stress resistance of torulopsis glabrata by utilizing a transcription factor Crz1p and belongs to the field of bioengineering. By deletion or overexpression of Cgcrz1 genes of torulopsis glabrata, the acid stress resistance of strains is reduced or improved correspondingly. The cell membrane fatty acid and sterol ingredients and proportion and permeability of deletion mutant strains Cgcrz1 delta under acid stress are compared, it is found that Crz1p is an essential transcription factor for torulopsis glabrata to resist the acid stress, and by the overexpression of Crz1p, the acid stress resistance of torulopsis glabrata can be improved.

The invention relates to a gene capable of regulating and controlling inhibition of vitamin C fermented strain acid production during acid stress and belongs to the technical fields of basic research on vitamin C prepared by fermentation and biological engineering. The key gene for regulating and controlling yield reduction of acid stress induced 2-Keto-L-Gulonic acid (2-KLG) in the production strains is determined, so a metabolic engineering strategy with high pertinence is generated. The expression condition of genes, in particular membrane transport protein genes, of acid-forming bacteria in the vitamin C mixed bacteria fermented system is analyzed by an expression profile chip technology. Compared with ketogenic gulonic acid bacteria subjected to single cultivation, the ketogenic gulonic acid bacteria subjected to mixed bacteria cultivation have 45 upregulated membrane transport protein genes and 15 down regulated membrane transport protein genes. The notable thing is that: 7 iron ion transport protein genes are inhibited to express. After acid stress, the iron ion transport protein genes are over expressed. During fermentation, the iron ions are added to inhibit mixed bacteria to ferment and generate acid. The result shows that the iron ion transport protein exerts reverse action in the process of yield reduction of 2-KLG generated by the acid stress induced mixed bacteria fermentation.

The invention discloses a method for increasing yield of pyruvic acid, belonging to the fermentation engineering field. The method is as follows: when Torulopsis glabrata (CCTCC NO: M202019) is used to ferment and produce pyruvic acid, aspartic acid is added to increase the acid stress resistance of Torulopsis glabrata. When the pH values are 5.5 and 4.5, the yields of pyruvic acid are separately55.8g/L and 30.4g/L which are separately increased by 12.4% (49.6g/L) and 48.4% (20.5g/L) than the control groups without aspartic acid; and the method has better technical effect and wide application prospect.

The invention relates to the microorganism field and discloses application of bacteria quorum sensing signal molecule AI-2 in improving bacteria acid resistance and/or oxygen resistance, and further discloses a method for improving the bacteria acid resistance and/or oxygen resistance. The method comprises the step that a compound of a structure shown by the formula (1) is added in the process that bacteria bear acid stress and/or oxygen stress. By the aid of the technical scheme, the compound of the structure shown by the formula (1) is added in the process that bacteria bear the acid stress and/or oxygen stress, and the compound can be converted into the bacteria quorum sensing signal molecule AI-2 in the bacteria growth environment, so that the influences of the acid stress and/or oxygen stress on bacteria can be reduced to the minimum.

The invention provides a culture method of lactic acid bacteria for feed and belongs to the technical field of microorganisms. The culture method includes: inoculating an activated lactobacillus seedsolution for feed to a fermentation culture medium with the pH being 6.3-6.7 and containing whey protein hydrolysate to perform shake culture so as to obtain the lactobacillus fermentation broth for feed, wherein the whey protein hydrolysate is obtained by hydrolyzing whey protein with a hydrochloric acid solution containing D-configuration acid. The culture method has the advantages that high-density culture can be achieved, and the used fermentation culture medium can prevent oxygen from damaging the lactic acid bacteria for feed, provide more ATP for the lactic acid bacteria for feed, satisfy the growth needs of the lactic acid bacteria for feed for a long time, and increase the acid stress resistance and reproduction number of the lactic acid bacteria for feed.

The invention discloses a high-performance feather degrading bacterium, having a classification name of Flavobacterium tirrenicum, has a strain number of X-Y4, and is collected at China Center for Type Culture Collection under CCTCC NO: M2019286 on April 23th, 2019. The invention also discloses application of Flavobacterium tirrenicum in the preparation of proline by degrading feather. The bacterium bred herein helps effectively achieve reuse of waste feather; the waste feather can be used as a liquid fertilizer for farmland irrigation; biomass resources are integrally utilized; environmentalpollution due to poultry farming is alleviated. The bacterium herein has high degrading capacity, the fermenting period is short, and a fermentation broth of the bacterium has proline content of 02% and above. The fermentation broth with rich proline can be prepared into liquid fertilizers which has the effects of promoting plant growth, relieving salt stress, relieving acid stress and the like, and the nutritional value and utilization rate of the fertilizers are increased.

The invention discloses escherichia coli engineering bacteria with improved acid stress resistance and application of the escherichia coli engineering bacteria, and belongs to the technical field of microbial engineering. According to the invention, aspartate carbamoyl transferase is overexpressed in escherichia coli to catalyze subunits PyrB, dihydroorotate dehydrogenase PyrD and Orotidine-5'-phosphate decarboxylase protein PyrF, so that the escherichia coli engineering bacteria with improved acid stress resistance, which can be widely applied to preparation of food, medicines, feeds and chemicals, is constructed successfully; and compared with a control strain, the stress resistance of the recombinant strain to itaconic acid, D-lactic acid and succinic acid is remarkably improved. The escherichia coli engineering bacteria are simple to operate and can be widely applied to industrial production.

The invention discloses a Lactobacillus engineered bacterium with improved acid stress resistance and application thereof, and belongs to the technical field of genetic engineering and microbial engineering. With a gene of an encoded energy-coupling factor transporter ATP enzyme cfA2 serving as a target gene and Lactobacillus as an expression host, the Lactobacillus engineered bacterium widely applicable to the preparation of foods, drugs, feeds and chemicals is successfully constructed; acid stress resistance of the Lactobacillus engineered bacterium is evidently improved, which is 598.7 times as high as that of a wild strain.

The invention discloses lactic acid bacteria engineering bacteria for improving the survival capacity in the acid stress environment, and belongs to the technical field of gene engineering and microorganism engineering. A gene of coded amino acid permease CtrA is used as a target gene, lactic acid bacteria are used as an expression host, and the lactic acid bacteria engineering bacteria capable ofbeing widely applied to preparation of food, medicine, feed and chemicals are successfully established. The survival capacity of the lactic acid bacteria engineering bacteria in the acid stress environment is remarkably improved, and the survival capacity is improved by 35.7 times compared with contrast strains.

The invention discloses lactic acid bacteria engineering bacteria with improved acid stress resistance and an application thereof and belongs to the technical field of genetic engineering and microbial engineering. The lactic acid bacteria engineering bacteria capable of being widely applied to preparing food, drugs, feeds and chemicals is obtained successfully by taking a gene encoding a thiaminetransportprotein ThiT as a target gene and lactic acid bacteria as an expression host. The acid stress resistance and the amino acid stress resistance of the lactic acid bacteria engineering bacteriaare improved obviously, and the acid stress resistance and the amino acid stress resistance are improved by 12.2 and 8.4 times to the highest extent compared with those of a mild strain.

The invention discloses a transcription factor Asg1p for regulating and controlling the acid stress resistance of Candida glabrata and belongs to the field of bioengineering. According to the invention, a gene-deleted mutant strain Cgasg1 Deta and a gene supplemented strain Cgasg1 Deta/CgASG1 are constructed by transforming Candida glabrata and then are subjected to a plate growth experiment and a cell viability test, the intracellular microenvironment of Candida glabrata is evaluated by analyzing the activity of intracellular h<+>-ATPase, intracellular Ph and the content of intracellular ROS under acid stress, and results show that Asg1p is a necessary transcription factor for Candida glabrata to resist acid stress.