(70a) Strategies for Assessing and Improving Microbial Utilization of Lignin-Derived Monomers

Authors: 
Davis, K., Iowa State University
Rover, M., Iowa State University
Salvachua, D., National Bioenergy Center, National Renewable Energy Laboratory
Smith, R. G., Iowa State University
Beckham, G. T., National Renewable Energy Laboratory
Wen, Z., Iowa State University
Brown, R. C., Iowa State University
Jarboe, L., Iowa State University
The economic viability of the biorefinery concept is limited by the valorization of lignin. One possible method of lignin valorization is biological upgrading with aromatic-catabolic microbes. In conjunction, lignin monomers can be produced by fast pyrolysis and fractionation. However, biological upgrading of these lignin monomers is limited by low water-solubility. Here, we address the problem of low water-solubility with an emulsifier blend containing approximately 70 wt% Tween® 20 and 30 wt% Span® 80. Pseudomonas putida KT2440 grew to an optical density (OD600) of 1.0±0.2 when supplied with 1.6 wt% emulsified phenolic monomer-rich product produced by fast pyrolysis of red oak. The emulsifier dose was 0.076±0.002 g emulsifier blend per g of phenolic monomer-rich product. This approach partially mitigated the toxicity of the water-soluble model phenolic monomer p-coumarate to the microbe. This study provides a proof of concept that processing of biomass-derived phenolics to increase aqueous availability can enhance microbial utilization.