Improved processes for producing bio-based nylon precursors having reduced organic and inorganic impurities are described herein. The processes generally comprise fermenting a microorganism engineered to produce lysine in a modified culture medium having low or reduced inorganic ion content, such as by employing a culture medium having an ammonium dicarboxylate buffering system that is preferably devoid of non-essential inorganic ions, and crystallizing the lysine directly from the spent lysine fermentation supernatant by adding a sufficient amount of a dicarboxylic acid. Such strategies aim to produce lysine dicarboxylate salt crystals that are employable in a downstream bioconversion step for the production of cadaverine dicarboxylate salts having reduced organic and inorganic impurities, which improve their downstream performance, for example in polymeration reactions for polyamide synthesis.

Provided are a microorganism comprising variant LysE, and an L-amino acid producing method using same. The variant LysE may improve L-amino acid excretion and/or production capacity compared to a wild type.

Provided are a microorganism comprising variant LysE, and an L-amino acid producing method using same. The variant LysE may improve L-amino acid excretion and/or production capacity compared to a wild type.

A genetically engineered strain having high-yield of L-valine is disclosed. Starting from Escherichia coli W3110, an acetolactate synthase gene alsS of Bacillus subtilis is inserted into a genome thereof and overexpressed; a ppGpp 3′-pyrophosphate hydrolase mutant R290E/K292D gene spoTM of Escherichia coli is inserted into the genome and overexpressed; a lactate dehydrogenase gene ldhA, a pyruvate formate lyase I gene pflB, and genes frdA, frdB, frdC, frdD of four subunits of fumaric acid reductase are deleted from the genome; a leucine dehydrogenase gene bcd of Bacillus subtilis replaces a branched chain amino acid transaminase gene ilvE of Escherichia coli; and an acetohydroxy acid isomeroreductase mutant L67E/R68F/K75E gene ilvCM replaces the native acetohydroxy acid isomeroreductase gene ilvC of Escherichia coli. Furthermore, the L-valine fermentation method is improved by using a two-stage dissolved oxygen control. The L-valine titer and the sugar-acid conversion rate are increased.

A genetically engineered strain having high-yield of L-valine is disclosed. Starting from Escherichia coli W3110, an acetolactate synthase gene alsS of Bacillus subtilis is inserted into a genome thereof and overexpressed; a ppGpp 3′-pyrophosphate hydrolase mutant R290E/K292D gene spoTM of Escherichia coli is inserted into the genome and overexpressed; a lactate dehydrogenase gene ldhA, a pyruvate formate lyase I gene pflB, and genes frdA, frdB, frdC, frdD of four subunits of fumaric acid reductase are deleted from the genome; a leucine dehydrogenase gene bcd of Bacillus subtilis replaces a branched chain amino acid transaminase gene ilvE of Escherichia coli; and an acetohydroxy acid isomeroreductase mutant L67E/R68F/K75E gene ilvCM replaces the native acetohydroxy acid isomeroreductase gene ilvC of Escherichia coli. Furthermore, the L-valine fermentation method is improved by using a two-stage dissolved oxygen control. The L-valine titer and the sugar-acid conversion rate are increased.

Provided is a method of preparing a granular feed additive. When the method of preparing a granular feed additive according to one exemplary embodiment is used, it is possible to prepare a granular feed additive including a high content of basic amino acids while preventing hygroscopicity and agglomeration caused by the basic amino acids. In addition, since the method of preparing a granular feed additive according to one exemplary embodiment may omit a process of using hydrochloric acid, which is generally used to neutralize basic amino acids, it is possible to simplify the process and to solve process problems caused by the use of hydrochloric acid.

The present disclosure discloses an Escherichia coli-based genetically-modified recombinant strain, a construction method therefor and use thereof. A mutant gene obtained by subjecting a wild-type deoB gene (ORF sequence is shown in a sequence 3902352-3903575 in GenBank accession No. CP032667.1) and a wild-type rhtA gene promoter sequence PrhtA (shown in a sequence 850520-850871 in GenBank accession No. AP009048.1) of an E. coli K12 strain and a derivative strain thereof (such as MG1655 and W3110) to site-directed mutagenesis, and a recombinant strain obtained therefrom can be used for the production of L-threonine, and compared with an unmutated wild-type strain, the obtained strain can produce L-threonine with a higher concentration and has good strain stability, and also has lower production cost as an L-threonine production strain.

The present disclosure discloses an Escherichia coli-based genetically-modified recombinant strain, a construction method therefor and use thereof. A mutant gene obtained by subjecting a wild-type deoB gene (ORF sequence is shown in a sequence 3902352-3903575 in GenBank accession No. CP032667.1) and a wild-type rhtA gene promoter sequence PrhtA (shown in a sequence 850520-850871 in GenBank accession No. AP009048.1) of an E. coli K12 strain and a derivative strain thereof (such as MG1655 and W3110) to site-directed mutagenesis, and a recombinant strain obtained therefrom can be used for the production of L-threonine, and compared with an unmutated wild-type strain, the obtained strain can produce L-threonine with a higher concentration and has good strain stability, and also has lower production cost as an L-threonine production strain.

The present disclosure relates to a method for producing L-tryptophan through the enhancement of prephenate dehydratase (PheA) activity.

The present disclosure relates to glycosaminoglycan-collagen copolymer compositions (such as hyaluronic acid-collagen copolymers and heparosan-collagen copolymer compositions) and medical applications thereof for augmenting soft tissue defects. The copolymer composition may be injected into tissues to correct defects or deficiencies, such as skin wrinkles, scars, and folds in dermal tissues.