Enzyme/whole-cell biotransformation of C1 compounds into ethanolamine by using an amine transaminase from Silicibacter pomeroyi

Multiple enzymatic biotransformation of methanol into ethanolamine via formaldehyde and glycolaldehyde was investigated. After discovery of an amine transaminase (ATA), the transamination reaction was connected to condensation of formaldehyde into glycolaldehyde. The ATA from Silicibacter pomeroyi (SpATA), which showed broad substrate spectrum from C4 to C14 aliphatic aldehydes, was able to catalyze the transamination of glycolaldehyde into ethanolamine. The kinetic studies revealed that K_M, k_cat, and k_cat/K_M values for glycolaldehyde were 4.3 mM, 2.4 s⁻¹, and 0.56 mM⁻¹ s⁻¹, respectively. The cascade transformation of methanol into ethanolamine via formaldehyde and glycolaldehyde by the isolated alcohol oxidase from Hypoxylon sp., glyoxylate carboligase from Escherichia coli, and the recombinant E. coli cells expressing the SpATA led to production of ethanolamine to a bioconversion of 42%. This study will contribute to valorization of C1 chemicals into industrially relevant multi-carbon products.