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.

The present invention provides a method for producing 2-methyl-butyric acid by fermentation using a bacterium belonging to the order Enterobacterales which has been modified to attenuate expression of a tyrB gene encoding a protein having tyrosine aminotransferase activity. The method also allows for production of a byproduct substance of 2-methyl-butyric acid during fermentation of the Enterobacterales bacterium having 2-methyl-butyric acid-producing ability.

Provided herein, among other things, is an engineered non-plant cell that produces a tropane alkaloid product, a precursor of a tropane alkaloid product, or a derivative of a tropane alkaloid product. A method for producing a tropane alkaloid, a precursor of a tropane alkaloid product, or a derivative of a tropane alkaloid product that makes use of the cell is also described.