65results about How to "Improve sugar-acid conversion rate" patented technology

The invention belongs to the technical field of gene engineering, and particularly relates to an escherichia coli gene engineering bacterium and a method for producing L-threonine by using the escherichia coli gene engineering bacterium. The gene engineering bacterium is characterized in that a promoter P<ppc> of phosphoenolpyruvate carboxylase gene (ppc) of an initial strain is replaced into a promoter P<zwf> of 6-phosphate dehydrogenase gene (zwf), so that the goal of regulating the L-threonine production capacity by glycine betaine is achieved. In the fermentation process, the glycine betaine is added, so that the L-threonine yield through shaking flask fermentation can reach 50 to 55g / L; the 5L fermentation tank yield reaches 120 to 150g / L; the saccharic acid conversion rate reaches 59 to 61 percent.

The invention discloses a method for producing an L-glutamic acid by fermentation in a staged gradient oxygen supply manner. The L-glutamic acid is obtained by inoculating a glutamic acid producing strain into a fermentation medium for fermentation and controlling the concentration of dissolved oxygen in a fermented liquid in a staged gradient oxygen supply manner. According to the method, the yield of the L-glutamic acid achieves over 155g / L and the glucose-acid conversion rate is raised to over 64% by means of respectively controlling different concentrations of dissolved oxygen at an inhibition stage, a logarithmic stage, a transformation stage and an acid production stage of the glutamic acid producing strain and through fed-batch fermentation; and the byproduct, namely lactic acid, during fermentation is reduced greatly.

The invention relates to an improved method for preparing L-tryptophan through a fermentation process, and concretely relates to a method for improving the saccharic acid conversion rate in an L-tryptophan fermentation process. In the invention, the content of acetic acid in the fermentation process is substantially reduced by controlling the dissolved oxygen level, the initial glucose concentration, the glucose limited feeding, the specific thallus growth rate and the like according to a cellar metabolic flux distribution regulating principle, so the thallus biomass, the L-tryptophan output and the saccharic acid conversion rate are substantially improved. The method effectively increases the conversion rate in the L-tryptophan fermentation process and substantially improves the L-tryptophan output without adding extra apparatuses or manpower investment, and is suitable for the industrialized production.

The invention provides a biomembrane-electrodialysis coupling continuous production technology of L-lactic acid. The production technology comprises the following steps: a clear liquid biomembrane column reactor is used to perform continuous anaerobic fermentation, the lactic acid producing strains are adsorbed by combined perforated ring filler, an ultrafiltration membrane is used to filter the fermentation liquor, thalli are blocked by the ultrafiltration membrane, the blocked thalli and liquid are sent back to the biomembrane column reactor, and L-lactic acid is separated through electrodialysis. The method provided by the invention uses the biomembrane column reactor to adsorb lactic acid producing strains on the membrane and uses the ultrafiltration membrane to block lactic acid bacteria, thus the thalli concentration and sugar utilization rate can be effectively increased, and the lactic acid concentration, the acid producing rate and the conversation rate from glucose to lacticacid can be increased greatly.

The invention discloses a method for improving fermentation-production citric acid yield through use of two-stage dissolved oxygen control technology, and belongs to the field of fermentation process optimization. In the first stage of fermentation (28-32 h), dissolved oxygen is controlled between 45% and 55%, and in the second stage of the fermentation (37-50 h), the dissolved oxygen is controlled between 35% and 45%. Through use of the two-stage dissolved oxygen control technology, the citric acid yield is significantly improved, and the highest sugar-acid conversion rate is 99%, whereas the sugar-acid conversion rate of a contrast embodiment is 86%. The two-stage dissolved oxygen control fermentation technology is simple and efficient, has important industrial application value, and at the same time has a certain guidance and enlightenment significance on fermentation production of other organic acids.

The invention discloses lactobacillus casei LC-N235 with collection number CCTCC (China Center for Type Culture Collection) No: M2012157. According to the invention, the original strain of lactobacillus casei LC-5 is mutated by low-energy nitrogen ion injection; the strain which resists high glucose, adopts EMP path reinforcement and utilizes lactic acid without decomposition can be screened by a high-glucose plate, a succinic acid plate and a pure-lactic acid plate; through fermentation re-screening, the L-lactic acid high-yield strain is screened and used as the original strain for next mutation; and the steps are repeated until the target strain lactobacillus casei LC-N235 is screened. The strain can effectively utilize the cheap corn flour saccharifying liquid to produce L-lactic acid by fermentation, and the saccharic acid conversion rate is high. In a 5L fermentation tank, the output of L-lactic acid reaches 173g / L, which is improved by 46.6% as compared with that of the L-lactic acid produced by fermenting the original strain; and the lactobacillus casei and the application thereof to produce L-lactic acid by fermentation provided by the invention have tremendous social significance and economic values.

The invention provides a glucose control process for increasing the yield of L-isoleucine. The glucose control process is a glucose sub-moderate sugar supplementing process; thalli are divided into four stages, namely an adaptation stage, a thalli expanding culture stage, an acid production peak stage and a decay stage; the thalli are Corynebacterium glutamate, have lysine defect types, and are fermented by adopting a base material high initial sugar; namely, 80-120 g / L of glucose is added to a base material at a time, a low-sugar feeding process is adopted in the middle and later periods, namely the feeding acceleration rate ranges from 5.20 g / (L.h) to 7.47 g / (L.h); and the thallus fermentation condition is dynamically and accurately regulated and controlled, and fermentation conversion of thalli is achieved, According to the method, the problems that the thallus adaptation period is long, the acid production peak period is short, the thallus enters the decay period in advance and thelike are solved, the glucose utilization rate is optimized, the saccharic acid conversion rate is increased, accumulation of by-products is reduced, and the heteroacid content is greatly reduced on the premise that the biomass and the acid production amount are not reduced.

A citric acid aspergillus niger seed continuous culture method based on a mycelium pellet dispersion technology comprises the steps as follows: (1), an aspergillus niger spore solution is inoculated to a seed culture medium and cultured and prepared into a mature seed solution; (2), the mature seed solution is treated by a disperser to obtain a dispersed mycelium seed solution; (3), part of the dispersed mycelium seed solution obtained in the step (2) is transferred to a fermentation medium for fermentation with 5%-15% of inoculum concentration, and the fermentation is finished when the reducing sugar concentration of the fermentation medium is lower than 0.5%; and (4), part of the dispersed mycelium seed solution obtained in the step (2) is inoculated to a seed culture medium with 5%-15% of inoculum concentration to be cultured and prepared into a next level of mature seed solution, and then the operation returns to the step (2), so that the continuous culture for aspergillus niger seeds is realized. According to the aspergillus niger seed continuous culture method provided by the invention, the tedious culture process of aspergillus niger spores can be directly reduced, simultaneously, the culture time of mature seeds can be effectively shortened, and the utilization rate of raw materials is increased.

The invention discloses an L-ammonium lactate tolerant bacterial strain and an application thereof in producing L-ammonium lactate through fermentation. According to the invention, low-energy nitrogen ions are injected in mutant original strains, and then the strains are screened by using a high-sugar tablet, a succinic acid tablet and an ammonium lactate tablet so as to obtain high-sugar-resistant and EMP approach reinforced strains which do not decompose and use a lactic acid. In a 3L fermentation tank, the strains are subjected to cultivation and acclimatization in a culture medium filled with critical-concentration ammonium lactate, and a bacteria liquid subjected to acclimatization of 72 hours is used as an original bacteria liquid of the next mutagenesis and acclimatization. The process is repeated until a target strain (Lactobacilluscasei) LC-An226 is screened. The strain has the characteristics of good ammonium lactate tolerance and high saccharic acid conversion rate. In a 5L fermentation tank, the output of L-ammonium lactate in the fermentation liquor reaches 206 g / L, and increased by 58.46% compared with the production of L-ammonium lactate by using original strains through fermentation, therefore, the strain has great social significance and economic values.

A method for producing L-lactic acid by Bacillus coagulans CGMCC No.2602 belongs to the technical field of microorganisms. In the invention, Bacillus coagulans CGMCC No.2602 is adopted, and under the condition of no oxygen supply, starchiness hydrolyzed sugar or dextrose is fermented by a semicontinuous intermittent fermentation way or an inter-sugar-compensating fermentation way to generate L-lactic acid with high optical purity. The invention has the advantages that the gemma property of the Bacillus coagulans is stable, and the L-lactic acid obtained by inoculating and fermenting the starchiness hydrolyzed sugar has high optical purity and rate of conversion of sugar and acid and short fermentation period; in addition, the semicontinuous intermittent fermentation way saves the time forpreparing seeds by a continuous reladling and subculturing method, shortens the fermentation period, enhances the fermentation strength and obtains the L-lactic acid with both relatively high rate ofconversion of sugar and acid and purity.

The invention relates to the field of microbial fermentation, and particularly discloses a method for producing D-lactic acid through fermentation. The method comprises the following step: inoculatinga fermentation culture medium with at least part of a carbon source provided by saccharification liquid against Lactobacillus plantarum with a preservation number of CGMCC No.16835. A production method of the saccharification liquid comprises the steps of mixing a slurry containing a starchy raw material and amylase for spray liquefaction, then conducting flash evaporation, cooling and heat preservation, and then mixing liquefaction liquid and a saccharifying enzyme for saccharification; the dosage of the saccharification liquid makes a content of carbon in the fermentation culture medium equal to 60-80 g / L; and conditions of lactic acid fermentation comprise a temperature of 37-45 DEG C, a pH value of 5.3-6.5, the time of 40-60 h, and the rotating speed of stirring of 50-150 rpm, and theinoculation quantity of the Lactobacillus plantarum makes Lactobacillus plantarum OD600 in a lactic acid fermentation system after inoculation is conducted range from 0.3 to 1. According to the method for producing the D-lactic acid through fermentation, the adopted raw materials have the characters of being wide in source and low in cost, by means of the provided method, production can be conducted in a wide pH value range and a wide temperature range, the workload of raw material pre-treatment is reduced, and the method for producing the D-lactic acid through fermentation has the charactersof being high in sugar utilization rate and conversion rate and short in production cycle.