Reductive amination cascades in cell-free and resting whole cell formats for valorization of lignin deconstruction products.

The selective introduction of amine groups within deconstruction products of lignin could provide an avenue for valorizing waste biomass while achieving a green synthesis of industrially relevant building blocks from sustainable sources. Here, we built and characterized enzyme cascades that create aldehydes and subsequently primary amines from diverse lignin-derived carboxylic acids using a carboxylic acid reductase (CAR) and an ω-transaminase (TA). Unlike previous studies that have paired CAR and TA enzymes, here we examine multiple homologs of each of these enzymes and a broader set of candidate substrates.