Efficient bioamination of lignin-derived vanillin to vanillylamine in dibutyl phthalate-water system

Lignin is one of the earth's most abundant renewable resources. Hence, achieving sustainable industry development in the future relies on obtaining a range of high-value chemicals from abundant and renewable biological resources. Vanillylamine is a basic upgrading product of vanillin in organic synthesis. It is also an important raw material for synthetic drugs, precursors, and additives. In this study, a two-phase reaction medium composed of organic solvent-water was established, and Escherichia coli CV was applied as ω-transaminase biocatalyst to the biosynthesis of vanillylamine from lignin-derived vanillin. Under optimized reaction conditions (pH 6.5, 35 °C) in a dibutyl phthalate (DBP)-water medium (1:9, vol/vol), vanillin (50 mM) was effectively transformed into vanillylamine by CV whole-cell biocatalyst containing ω-transaminase with amine donor L-Alanine (L-Ala:vanillin=12:1, mol/mol). Also, benzaldehyde, anisaldehyde, and veratraldehyde (50 mM) could be fully converted into the corresponding amines. This work provides an efficient and environmentally friendly method for the preparation of vanillylamine and its derivatives from lignin-based feedstocks.