Provided is process for the synthesis of at least one functionalized organic polysulfide.

Provided is process for the synthesis of at least one functionalized organic polysulfide.

The present disclosure relates to modified homoserine dehydrogenase and a method for producing a homoserine-derived L-amino acid using the same.

The present disclosure relates to modified homoserine dehydrogenase and a method for producing a homoserine-derived L-amino acid using the same.

A DNA expression construct comprising a polynucleotide encoding an unnatural UstD enzyme, the unnatural enzyme itself, and a method of making gamma-hydroxy amino acids by contacting an aldehyde-containing substrate, an amino acid, and the unnatural, purified UstD enzyme under conditions and for a time sufficient to react at least a portion of the aldehyde-containing substrate with at least a portion of the amino acid, to yield a gamma-hydroxy amino acid product.

A DNA expression construct comprising a polynucleotide encoding an unnatural UstD enzyme, the unnatural enzyme itself, and a method of making gamma-hydroxy amino acids by contacting an aldehyde-containing substrate, an amino acid, and the unnatural, purified UstD enzyme under conditions and for a time sufficient to react at least a portion of the aldehyde-containing substrate with at least a portion of the amino acid, to yield a gamma-hydroxy amino acid product.

The present invention generally relates to the microbiological industry, and specifically to the production of L-serine or L-serine derivatives using genetically modified bacteria. The present invention provides genetically modified microorganisms, such as bacteria, wherein the expression of genes encoding for enzymes involved in the degradation of L-serine is attenuated, such as by inactivation, which makes them particularly suitable for the production of L-serine at higher yield. The present invention also provides means by which the microorganism, and more particularly a bacterium, can be made tolerant towards higher concentrations of serine. The present invention also provides methods for the production of L-serine or L-serine derivative using such genetically modified microorganisms.

The present disclosure relates to a method for preparing L-cysteine crystals, and L-cysteine crystals prepared by the method. Through the method for preparing L-cysteine crystals of the present disclosure, L-cysteine crystals can be obtained from a natural L-cysteine fermentation broth with a high recovery rate and/or purity without a chemical reaction or the use of an artificial synthetic compound.

The present disclosure relates to a method for preparing L-cysteine crystals, and L-cysteine crystals prepared by the method. Through the method for preparing L-cysteine crystals of the present disclosure, L-cysteine crystals can be obtained from a natural L-cysteine fermentation broth with a high recovery rate and/or purity without a chemical reaction or the use of an artificial synthetic compound.

The present disclosure relates to an additive used in a methionine preparation process, and a methionine preparation method. The additive provided by the present disclosure is a mixture containing components A, B, and C; component A has a structure represented by the following general formula (1); component B has a structure represented by the following general formula (2); component C is silicone oil; RCON(CH.sub.3)CH.sub.2CH.sub.2SO.sub.3Na (1). The methionine preparation method provided in the present invention comprises subjecting methionine to crystallization and/or recrystallization in the presence of the additive provided by the present disclosure. The additive provided by the present disclosure results in uniform emulsification, has good stability, can be used stably for a long time, and is suitable for a continuous crystallization process. The prepared methionine crystal has a good crystal form, a large bulk density, and good flowability. In addition, according to the methionine preparation method of the present disclosure, a crystallization system can operate continuously and stably for a long time without obvious foaming, and the crystallization process of the methionine product can proceed smoothly.

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