(633e) Biological Conversion of Thermochemical Wastewater Streams

Thermochemical biomass conversion processes such as fast pyrolysis and catalytic fast pyrolysis produce aqueous waste streams that contain aromatic, acid, and aldehyde compounds. These aqueous waste streams often comprise a significant fraction of biomass-derived carbon, and are currently slated for wastewater treatment, representing a cost burden to the thermochemical biorefinery. Prior to developing a microbial valorization strategy, we first conducted a comprehensive analytical survey of thermochemical aqueous waste streams from fast pyrolysis and catalytic fast pyrolysis, identifying and quantifying over 200 compounds at near-complete mass closure. This detailed analytical effort enabled the ability to tailor a microbial strategy for conversion of the wide range of aromatic, acidic, and aldehyde compounds to value-added chemicals using an engineered, aerobic monoculture strategy. Specifically, we are engineering a robust aromatic-catabolic microbe, Pseudomonas putida KT2440, to upgrade aqueous streams from pilot-scale pyrolysis operations. Beyond a substantial expansion in substrate catabolism, we have also demonstrated that over-expression of the native protein quality control machinery enables a dramatic improvement in microbial tolerance, a key challenge for the toxic streams produced from thermochemical processing of biomass.