Facile synthesis of 2-hydroxyacetophenone from racemic styrene oxide catalyzed by engineered enzymes

We describe a system that allows for biocatalyzed in vivo synthesis of α-hydroxy ketones from racemic epoxide starting material by in vivo co-expression of native and engineered epoxide hydrolase and alcohol dehydrogenases. The constructed expression system exploits the host cell metabolism for supply and regeneration of precious nicotinamide dinucleotide coenzyme. Racemic styrene oxide added to growth medium passively enters the cells and is hydrolyzed into (1R)-phenylethane-1,2-diol, which is subsequently oxidized to the acyloin 2-hydroxyacetophenone. Produced 2-hydroxyacetophenone escapes the cells via passive diffusion into the growth medium. Thus, co-expression of potato epoxide hydrolase and engineered alcohol dehydrogenase variants can be employed for robust and facile production of 2-hydroxyacetophenone from racemic styrene oxide.