P21: Hybrid processing: fermentation of pyrolytic bio-oil for production of biofuel and biochemicals

Biomass is an abundant and promising feedstock for production of renewable fuels and chemicals. The key challenge in economical utilization of the biomass is the degradation of cellulose and hemicellulose in the biomass into fermentable substrates. The biological platform, which depolymerizes biomass into sugars by enzymes and ferments the sugars into fuels or chemicals, still has a high cost after many years research. Our research team has established a hybrid processing platform where a pyrolysis process is first used to covert biomass into fermentable substrates and a biological process is used to ferment those substrates into fuels and chemicals. Compared with biological platform, the hybrid processing has inherent advantages of (1) elimination of complex pretreatment and high enzyme costs, and (2) capability of using all components of biomass including lignin. Currently, the key hurdle for hybrid processing is the presence of contaminants in the pyrolysis product that severely inhibit the microorganism fermentation. We address this problem with two approaches: 1) Metabolic evolution to increase the robustness of biocatalyst to overcome the inhibition; 2) Pretreatment of the bio-oil to remove or reduce the abundance of contaminant compounds. Progress on these two aspects in our research program will be described.