The present invention provides ketoreductase variants having activity on both (R)-(?)-1,3-butanediol and (S)-(+)-1,3-butanediol, and the computational methodology for designing the above mentioned ketoreductase variants. The ketoreductase variants disclosed in the present application can catalyze the reaction of synthesizing 4-hydroxy-2-butanone from racemic 1,3-butanediol, which has industrial application prospects.

The present invention relates to a microorganism of the genus Corynebacterium, which has an enhanced activity of aspartate ammonia-lyase and/or aspartate aminotransferase, and thus has an enhanced ability to produce L-arginine, and to a method of producing L-arginine using the microorganism of the genus Corynebacterium.

Enzyme cascade reactions, wherein the product of a first enzyme is the substrate of a second enzyme and so forth, were found to be enhanced by the presence of peptides. It is believed that the peptides operate by forming coacervates, which are membrane-less compartments where, in the case of coacervates formed by peptides, the liquid-liquid phase separation involves water as the continuous phase both inside and outside the coacervate.

An R-3-aminobutyric acid preparation method with high efficiency and high stereoselectivity. The method comprises using aspartase with stereoisomerization catalytic activity derived from Escherichia coli to efficiently convert butenoic acid into R-3-aminobutyric acid. After only 24 h of reaction, the conversion rate is as high as ?98%, and the ee value is ?99.9%. The conversion efficiency is greatly improved, the reaction time is shortened, and the production costs are reduced. The method features a high yield, a high conversion rate, low costs, a short production cycle, a simple process, ease of enlargement, suitability for mass production and the like.

Described herein is a one-pot, four-enzyme cascade of enzymes, three bound to quantum dots with one enzyme free in solution, for the conversion in vitro of fumarate to 1,3-diaminopropane. The cascade operates via two distinctly different enzymatic channeling mechanisms which simultaneously function to increase the overall rate. The first three enzymes of the pathway (AspB->LysC->Asd) were able to engage in channeling in a nanoparticle displayed format, but addition of the last two enzymes to this pathway in this format (AspB->LysC->Asd->Dat->Ddc) did not result in complete channeling through the entire pathway to the final diaminopropane product. Surprisingly, replacement of the last two enzymes (Dat->Ddc) with a naturally occurring fused Dat-Ddc hybrid (Daba) provided for full channeling in this system (AspB->LysC->Asd->Daba).