33 results about "Lactic acid dehydrogenase activity" patented technology

A high flux of metabolites from pyruvate to 2,3-butanediol in Lactobacillus plantarum was achieved through genetic engineering. Substantial elimination of lactate dehydrogenase activity in the presence of heterologously expressed butanediol dehydrogenase activity led to 2,3 butanediol production that was at least 49% of the total of major pyruvate-derived products.

The invention discloses a method for stabilizing activity of alpha-hydroxybutyricdehydrogenase and lactic dehydrogenase of quality-control serum, comprising the step of freezing and drying a mixture composed of other proteins, trehalose, mannite, glycine, quality-control serum and buffer solution. By the method in the invention, a freeze-drying quality-control serum containing alpha-HBDH and LDH and with stable properties and low price can be provided, the freeze-drying alpha-HBDH and LDH quality-control serum is stable and can be stored in a long term, the activity of the two enzymes of alpha-HBDH and LDH has no obvious change after hydrated reconstruction.

Succinic acid is produced by allowing a bacterium modified to enhance fumarate reductase activity or cell preparation thereof to react with an organic raw material in a reaction solution containing one of a carbonate ion, a bicarbonate ion, and carbon dioxide gas to generate succinic acid. More preferably, succinic acid is produced by allowing a bacterium modified to enhance activities of fumarate reductase and pyruvate carboxylase and decrease lactate dehydrogenase activity or cell preparation thereof to react with an organic raw material in a reaction solution containing one of a carbonate ion, a bicarbonate ion, and carbon dioxide gas to generate succinic acid. Succinic acid is obtained by collecting the produced succinic acid.

The present invention provides a method for producing lactic acid in a recombinant yeast cell culture using glucose as carbon source comprising a first, seed fermentation stage to produce biomass wherein the yeast is cultivated in a culture medium at a p H of 5 to 7, followed by a second, a production fermentation stage with biomass from the seed fermentation to produce lactic acid, wherein the yeast is cultivated in a culture medium at low p H using a yeast strain that is engineered to have lactate dehydrogenase (LDH) activity and optionally has decreased or knocked- out pyruvate decarboxylase (PDC) activity.

Succinic acid is produced by allowing a bacterium modified to enhance fumarate reductase activity or cell preparation thereof to react with an organic raw material in a reaction solution containing one of a carbonate ion, a bicarbonate ion, and carbon dioxide gas to generate succinic acid. More preferably, succinic acid is produced by allowing a bacterium modified to enhance activities of fumarate reductase and pyruvate carboxylase and decrease lactate dehydrogenase activity or cell preparation thereof to react with an organic raw material in a reaction solution containing one of a carbonate ion, a bicarbonate ion, and carbon dioxide gas to generate succinic acid. Succinic acid is obtained by collecting the produced succinic acid.

A thermophilic microorganism lacks lactate dehydrogenase activity and preferably contains an active pyruvate formate lyase pathway. The thermophilic microorganism contains a gene encoding an NAD-linked formate dehydrogenase. The gene encoding an NAD-linked formate dehydrogenase is preferably a codon optimised version of the gene encoding a thermostable NAD-linked formate dehydrogenase. DNA constructs allow stable expression of the gene encoding an NAD-linked formate dehydrogenase in the thermophilic microorganism. The DNA constructs are based upon use of an insertion sequence to achieve stable expression or recombination to insert the gene encoding an NAD-linked formate dehydrogenase into the lactate dehydrogenase gene, thus achieving gene knockout and new functionality in a single step. The microorganisms are useful in fermentation of sugars to produce ethanol.

This invention provides a polynucleotide that encodes a protein having lactate dehydrogenase activity and such protein that can be used for producing D-lactic acid. This polynucleotide has the nucleotide sequence as shown in SEQ ID NO: 1 (a), and it hybridizes under stringent conditions with a probe comprising all or part of the nucleotide sequence as shown in SEQ ID NO: 1 or a complementary strand thereof and encodes a protein having D-lactate dehydrogenase activity (b).

A thermophilic microorganism lacks lactate dehydrogenase activity and preferably contains an active pyruvate formate lyase pathway. The thermophilic microorganism contains a gene encoding an NAD-linked formate dehydrogenase. The gene encoding an NAD-linked formate dehydrogenase is preferably a codon optimised version of the gene encoding a thermostable NAD-linked formate dehydrogenase. DNA constructs allow stable expression of the gene encoding an NAD-linked formate dehydrogenase in the thermophilic microorganism. The DNA constructs are based upon use of an insertion sequence to achieve stable expression or recombination to insert the gene encoding an NAD-linked formate dehydrogenase into the lactate dehydrogenase gene, thus achieving gene knockout and new functionality in a single step. The microorganisms are useful in fermentation of sugars to produce ethanol.

The present disclosure pertains to a genetically modified microorganism that satisfies some of specific requirements. The specific requirements include: (I) compared to a wild type microorganism, having reduced or inactivated succinate dehydrogenase activity or fumarate reductase activity; (II) compared to a wild type microorganism, having reduced or inactivated lactate dehydrogenase activity; (III) having a modified phosphoenolpyruvate carboxylase activity and thus showing resistance against the feedback inhibition by aspartic acid in wild type phosphoenolpyruvate carboxylase activity, or having an exogenous phosphoenolpyruvate carboxylase activity and thus showing higher resistance against the feedback inhibition by aspartic acid than wild type phosphoenolpyruvate carboxylase activity shown by a wild type microorganism; and (IV) compared to a wild type microorganism, having reduced or inactivated pyruvate : quinone oxidoreductase.

The invention discloses a preparation method and an application of a protein nutritional food with an anti-fatigue efficacy, belongs to the field of functional foods and particularly relates to a food with a significant efficacy on sports fatigue relieving. The protein nutritional food prepared by adopting the method disclosed by the invention comprises the following main nutritional base materials in parts by weight: 44-46 parts of soy protein isolate and 53-55 parts of whey protein according to the detection of the nitrogen content of each protein. By adopting the protein nutritional food with equal nitrogen ratio, through seven-week nutrition intervention in a rat after loaded swimming in still water, the lactic dehydrogenase activity in the rat can be remarkably increased and the loaded swimming exhaustive time of the rat is prolonged on the premise of not increasing the weight of the rats. The food has an obvious efficacy on sports fatigue relieving and the average loaded swimming exhaustive time of the rat is up to 135 seconds, so that the food has a good utilization value in anti-fatigue functional food development.

Rice protein concentrates prepared at low temperature exhibit improved functionality and beneficial physiological benefits, including lowered cholesterol and enhanced lactic acid dehydrogenase activity, without an increase in blood urea nitrogen. The rice protein concentration could be made into a wet dough with comparatively less water than a soy protein concentrate. Use of the rice protein concentrate thus improved processing steps in the formulation of a food article containing the concentrate. The food product advantageously shows an extending shelf life and improved palatable texture.

Provided are: a bacterium belonging to the genus Rhizopus, which has an improved lactic acid production ability; and a method for producing lactic acid using the bacterium. A method for improving the activity of lactate dehydrogenase in a bacterium belonging to the genus Rhizopus, comprising germinating a spore of the bacterium belonging to the genus Rhizopus in a culture solution containing a surfactant under specified conditions to produce a mycelium of the bacterium; and a method for producing lactic acid using the mycelium of the bacterium belonging to the genus Rhizopus.

The present invention relates to a method for preparing a D-lactic acid-producing strain modified to inhibit L-lactate dehydrogenase (L-LDH) activity and to introduce D-lactate dehydrogenase (D-LDH) activity in an L-lactic acid-producing strain, a mutated D-lactic acid-producing strain prepared by the above method, and a method for producing D-lactic acid including the steps of culturing the strain and recovering D-lactic acid from the culture media.

The present invention provides a method for producing lactic acid in a recombinant yeast cell culture using glucose as carbon source comprising a first, seed fermentation stage to produce biomass wherein the yeast is cultivated in a culture medium at a pH of 5 to 7, followed by a second, a production fermentation stage with biomass from the seed fermentation to produce lactic acid, wherein the yeast is cultivated in a culture medium at low p H using a yeast strain that is engineered to have lactate dehydrogenase (LDH) activity and optionally has decreased or knocked-out pyruvate decarboxylase (PDC) activity.

The invention discloses a preparation method and an application of a protein nutritional food with an anti-fatigue efficacy, belongs to the field of functional foods and particularly relates to a food with a significant efficacy on sports fatigue relieving. The protein nutritional food prepared by adopting the method disclosed by the invention comprises the following main nutritional base materials in parts by weight: 44-46 parts of soy protein isolate and 53-55 parts of whey protein according to the detection of the nitrogen content of each protein. By adopting the protein nutritional food with equal nitrogen ratio, through seven-week nutrition intervention in a rat after loaded swimming in still water, the lactic dehydrogenase activity in the rat can be remarkably increased and the loaded swimming exhaustive time of the rat is prolonged on the premise of not increasing the weight of the rats. The food has an obvious efficacy on sports fatigue relieving and the average loaded swimming exhaustive time of the rat is up to 135 seconds, so that the food has a good utilization value in anti-fatigue functional food development.

The invention discloses a measuring method for lactic dehydrogenase activity based on a titanium dioxide film field-effect tube. The measuring method comprises the following steps: (1) preparing a titanium dioxide film through a sol-gel method: cleaning a silicon plate, preparing a solution, rotatably coating and annealing; (2) connecting a coating electrode to three electrodes; (3) performing enzyme immobilization; (4) detecting enzyme activity: using KEITHLEY 4200 to test electrical properties of the field-effect tube for enzyme activity detection, testing an I-V curve of lactic dehydrogenase of D-S under different grid voltages, and performing instant detection after dropwise adding lactic acids of different concentrations, detecting on multiple reaction time points, and observing I-V curve changes of D-S at different reaction times. The measuring method does not need test paper, is short in test period, is quick in response, and can be used for realizing quick detection for enzymeactivity. Needed enzyme is low in concentration, is small in size, and can be immobilized enzyme. The measuring method is simple, and provides a novel method for measuring enzyme activity in blood serum.

The invention discloses an application of dioscin in preparation of a liver-protecting pharmaceutical preparation. The pharmaceutical preparation can obviously inhibit increase of activity of aminotransferase and lactate dehydrogenase due to medicines (carbon tetrachloride or paracetamol) and alcohol, and reduce the liver indices, thereby performing the liver-protecting function; the pharmaceutical preparation can enhance the activity of SOD, reduce the content of MDA, increase the content of GSH and inhibit liver lipide overoxidation induced by medicines (carbon tetrachloride or paracetamol); and the pharmaceutical preparation can also reduce the content of TG and TC and inhibit the liver steatosis caused by alcohol. The dioscin can be used as the raw material to prepare various preparation formulations for clinic applications according to pharmaceutic related requirements and clinic requirements, such as tablets, capsules, injections, oral liquids, granules and the like. The invention is safe (no toxicity or side effect), convenient, economical and the like.

The invention discloses a method for stabilizing activity of alpha-hydroxybutyricdehydrogenase and lactic dehydrogenase of quality-control serum, comprising the step of freezing and drying a mixture composed of other proteins, trehalose, mannite, glycine, quality-control serum and buffer solution. By the method in the invention, a freeze-drying quality-control serum containing alpha-HBDH and LDH and with stable properties and low price can be provided, the freeze-drying alpha-HBDH and LDH quality-control serum is stable and can be stored in a long term, the activity of the two enzymes of alpha-HBDH and LDH has no obvious change after hydrated reconstruction.