Efficient synthesis of vanillylamine through bioamination of lignin-derived vanillin by recombinant E. coli containing ω-transaminase from Caulobacter sp. D5 in dimethyl sulfoxide-water.

Lignin is a plentiful and readily accessible renewable resource. Vanillylamine is a crucial raw material used to synthesize pharmaceuticals and high-value furan compounds that can be acquired by aminating lignin-derived vanillin (Van). However, effectually achieving the biocatalytic synthesis of vanillylamine has remained challenging. In this study, a dimethyl sulfoxide (DMSO)-HO (1:9, vol/vol) bioreaction medium was constructed, and a recombinant E. coli ATA1012 carrying ω-transaminase from Caulobacter sp. D5 was used as the ω-transaminase biocatalyst to acquire the effectual biocatalytic synthesis of vanillylamine. Under optimized bioreaction conditions (37 ℃ and pH 7.5) by supplementary of isopropylamine (IPA) (Van/IPA = 1:5, mol/mol), 80-100 mM Van could be effectually converted by ATA1012 whole cells in DMSO-HO (1:9, vol/vol) within 12 h, yielding 91.2 %-95.4 % vanillylamine, with >99 % selectivity. An efficient amination process was developed using ATA1012 with superior transaminase catalytic activity and substrate tolerance to effectively convert Van to vanillylamine in a DMSO-HO medium.