Provided is an immobilized enzyme, a preparation method and use thereof. The immobilized enzyme includes an enzyme and an amino resin carrier for immobilizing the enzyme, and the enzyme is selected from any one of the following enzymes: transaminase, ketoreductase, monooxygenase, ammonia-lyase, ene reductase, imine reductase, amino acid dehydrogenase, and nitrilase. The amino resin carrier is an amino resin carrier modified by a cross-linking agent, and the cross-linking agent is a cross-linking agent treated by a polymer. By means of modifying the amino resin carrier with the cross-linking agent treated by the polymer, the enzyme immobilized on the amino resin carrier may easily form a network cross-linking, such that the immobilization effect of the enzyme is more stable, thereby the recycling efficiency of the enzyme is improved.

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.

The present disclosure provides recombinant bacterial cells that have been engineered with genetic circuitry which allow the recombinant bacterial cells to sense a patients internal environment and respond by turning an engineered metabolic pathway on or off. When turned on, the recombinant bacterial cells complete all of the steps in a metabolic pathway to achieve a therapeutic effect in a host subject. These recombinant bacterial cells are designed to drive therapeutic effects throughout the body of a host from a point of origin of the microbiome. Specifically, the present disclosure provides recombinant bacterial cells comprising a heterologous gene encoding an improved leucine catabolism enzyme with higher activity and/or specificity for leucine over other branched chain amino acids, such as isoleucine or valine. The disclosure further provides pharmaceutical compositions comprising the recombinant bacteria, and methods for treating disorders involving the catabolism of leucine, isoleucine, and/or valine using the pharmaceutical compositions disclosed herein.

A method is useful for the biocatalytic synthesis of proteinogenic L-amino acids, such as L-alanine, L-valine, L-methionine, L-leucine, L-isoleucine or L-phenylalanine from a respective aldehyde and carbon dioxide. In particular, the method is useful for the biocatalytic synthesis of L-methionine from 3-methylthio-propanal (methional) and carbon dioxide.

Disclosed herein is a process for preparing enantioenriched (S)-2-aminonon-8-enoic acid by amination of 2-oxonon-8-enoic acid in the presence of an enzyme and an ammonia source.

The present disclosure relates to the use of an amino acid dehydrogenase in combination with a cofactor regenerating system comprising a ketoreductase. In particular embodiments, the process can be used to prepare L-tert-leucine using a leucine dehydrogenase.

Methods and systems for the production of alcohols are described. A two stage process is utilized, where fermentation in a first stage produces an intermediate product, such as an amino acid or organic acid, from a carbon containing feedstock. A second stage produces alcohol by fermentation of this intermediate product.

A method is useful for the biocatalytic synthesis of proteinogenic L-amino acids, such as L-alanine, L-valine. L-methionine. L-leucine, L-isoleucine or L-phenylalanine from a respective aldehyde and carbon dioxide. In particular, the method is useful for the biocatalytic synthesis of L-methionine from 3-methylthio-propanal (methional) and carbon dioxide.

Disclosed herein is a process for preparing enantioenriched (S)-2-aminonon-8-enoic acid by amination of 2-oxonon-8-enoic acid in the presence of an enzyme and an ammonia source.

Provided herein are non-naturally occurring microbial organisms having biosynthetic pathways for production of target products and one or more genetic modifications that reduce a byproduct of the biosynthetic pathway. Compositions of target products from such cells and methods of using such cells are provided.