Alkane and wax ester production from lignin related aromatic compounds.

Lignin has potential as a sustainable feedstock for microbial production of industrially relevant molecules. However, the required lignin depolymerization yields a heterogenic mixture of aromatic monomers that are challenging substrates for the microorganisms commonly used in industry. Here, we investigated the properties of lignin related aromatic compounds (LRAs), namely coumarate, ferulate, and caffeate, in the synthesis of biomass and products in a LRA-utilizing bacterial host Acinetobacter baylyi ADP1. The biosynthesis products, wax esters and alkanes, are relevant compounds for the chemical and fuel industries. Here, wax esters were produced by a native pathway of ADP1, whereas alkanes were produced by a synthetic pathway introduced to the host. Using individual LRAs as substrates, the growth and product formation were monitored with internal biosensors and off-line analytics. Of the tested LRAs, coumarate was the most propitious in terms of product synthesis. Wax esters were produced from coumarate with a yield and titer of 37 mg/gcoumarate and 202 mg/l, whereas alkanes were produced with a yield of 62.3 µg/gcoumarate and titer of 152 µg/l. This study demonstrates the microbial preference for certain LRAs, and highlights the potential of A. baylyi ADP1 as a host for LRA upgrading to value-added products. This article is protected by copyright. All rights reserved.