The present invention relates to a method of separating amino acids from an aqueous solution comprising amino acids as well as proteins and/or protein decomposition products by combining phosphoric acid with the aqueous solution to precipitate an amino acid monophosphate. The precipitate so formed may be separated from the aqueous solution and used as such, e.g. in plant fertilizer compositions. The precipitate may be redissolved in a suitable liquid, after which phosphate and amino acid may be separated following conventional methods. In either case, the present invention enables highly selective precipitation of arginine and/or lysine monophosphate as crystals.

Disclosed is a recombinant microorganism capable of growing using only carbon dioxide and formic acid by introducing and improving a metabolic pathway for synthesizing pyruvic acid from carbon dioxide and formic acid to enhance pyruvic acid synthesis efficiency and performing additional genetic manipulation, and a method for producing useful substances using the same. Advantageously, the recombinant microorganism is capable of synthesizing pyruvic acid, a C3 organic compound, at a remarkably improved rate, and in particular, grows well even in a medium containing only carbon dioxide and formic acid as carbon sources without a glucose supply, and is thereby capable of synthesizing pyruvic acid and various high value-added compounds using the same as an intermediate product in an economically efficient manner.

Disclosed is a recombinant microorganism capable of growing using only carbon dioxide and formic acid by introducing and improving a metabolic pathway for synthesizing pyruvic acid from carbon dioxide and formic acid to enhance pyruvic acid synthesis efficiency and performing additional genetic manipulation, and a method for producing useful substances using the same. Advantageously, the recombinant microorganism is capable of synthesizing pyruvic acid, a C3 organic compound, at a remarkably improved rate, and in particular, grows well even in a medium containing only carbon dioxide and formic acid as carbon sources without a glucose supply, and is thereby capable of synthesizing pyruvic acid and various high value-added compounds using the same as an intermediate product in an economically efficient manner.

The present invention discloses a kind of method for preparing L-citrulline by using Aeromonas sp., which is related to the technical field of bioengineering. The said method consists of following steps: fermenting Aeromonas sp. in a culture medium to obtain seed liquid, and the liquid is inoculated into the fermenter at an inoculum size of 1-2% by volume. The initial pH is 3.5, and the pH in the medium is controlled below 4.0 all the time. Then, conducts shaking culture for 15-20 hours to obtain the fermentation broth. The fermentation broth is centrifuged to obtain precipitation solution and supernatant; Use the said supernatant to prepare the substrate solution, and the pH of the substrate solution is controlled at 3-5, and then, add the precipitation solution to react at the temperature of 30-50° C., the reaction time is 5-8 hours. After reaction, the L-citrulline is obtained by the method of concentration and crystallization. The present invention provides a method for preparing L-citrulline with low cost, high L-citrulline content and high purity.

The present invention discloses a kind of method for preparing L-citrulline by using Aeromonas sp., which is related to the technical field of bioengineering. The said method consists of following steps: fermenting Aeromonas sp. in a culture medium to obtain seed liquid, and the liquid is inoculated into the fermenter at an inoculum size of 1-2% by volume. The initial pH is 3.5, and the pH in the medium is controlled below 4.0 all the time. Then, conducts shaking culture for 15-20 hours to obtain the fermentation broth. The fermentation broth is centrifuged to obtain precipitation solution and supernatant; Use the said supernatant to prepare the substrate solution, and the pH of the substrate solution is controlled at 3-5, and then, add the precipitation solution to react at the temperature of 30-50° C., the reaction time is 5-8 hours. After reaction, the L-citrulline is obtained by the method of concentration and crystallization. The present invention provides a method for preparing L-citrulline with low cost, high L-citrulline content and high purity.

Disclosed is a modified microorganism producing putrescine or ornithine, and a method for producing putrescine or ornithine using the same.

Disclosed is a modified microorganism producing putrescine or ornithine, and a method for producing putrescine or ornithine using the same.

The present invention provides a method for producing a basic L-amino acid such as, for example, L-ornithine L-citrulline, L-arginine, L-histidine, and L-lysine by fermentation using a bacterium belonging to the family Enterobacteriaceae which has been modified to overexpress a gene encoding a protein having L-methionine/branched-chain amino acid exporter activity.

The present invention provides a method for producing a basic L-amino acid such as, for example, L-ornithine L-citrulline, L-arginine, L-histidine, and L-lysine by fermentation using a bacterium belonging to the family Enterobacteriaceae which has been modified to overexpress a gene encoding a protein having L-methionine/branched-chain amino acid exporter activity.

A microorganism of the genus Corynebacterium producing L-arginine, and a method for producing L-arginine using the same.