Efficient synthesis of syringyl alcohol through bioreduction of lignin-derived syringaldehyde by newly constructed recombinant Escherichia coli C165F-V231D

Syringyl alcohol is an important lignin-derived aromatic alcohol with potential utility in the fragrance and pharmaceutical research. In this study, it was biologically synthesized from syringaldehyde. The recombinant Escherichia coli C165F-V231D expressing alcohol dehydrogenase K p ADH from Kluyveromyces polyspora enabled the effective biotransformation of syringaldehyde. Based on structural analysis and previous work for mutation of 165C to 165F and 231 V to 231D in K p ADH. This variant was created, demonstrating a markedly increased catalytic activity under low dimethyl sulfoxide (DMSO) concentrations. C165F-V231D activity could be improvemed significantly in DMSO-H 2 O (5:95, V/V). Eventually, C165F-V231D cells transformed syringaldehyde (25 mM) to syringyl alcohol in 99.7% analytical yield. This work provides a sustainable biocatalytic strategy for the synthesis of syringyl alcohol from lignin-derived aldehydes, deserves the further development lignin valorization and the green synthesis of bio-derived aromatic alcohols.