Alkane and wax ester production from lignin derived molecules

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-derived molecules (LDMs), namely coumarate, ferulate, and caffeate, in the synthesis of biomass and products in a LDM-utilizing bacterial hostAcinetobacter baylyiADP1. The biosynthesis products, wax esters and alkanes, are relevant compounds for the chemical and fuel industries. InA. baylyiADP1, wax esters are produced by a native pathway, whereas alkanes are produced by a synthetic pathway introduced to the host. Using individual LDMs as substrates, the growth, product formation, and toxicity to cells were monitored with internal biosensors. Of the tested LDMs, coumarate was the most propitious in terms of product synthesis. Wax esters were produced from coumarate with a yield and titer of 40 mg /gcoumarateand 221 mg/L, whereas alkanes were produced with a yield of 62.3 μg /gcoumarateand titer of 152 μg/L. This study demonstrates the microbial preference for certain LDMs, and highlights the potential ofA. baylyiADP1 as a convenient host for LDM upgrading to value-added products.