2-02: Identification of inhibitory mechanisms in the conversion of lignocellulosic hydrolysate to ethanol by Escherichia coli using comparative multiomic fermentation with synthetic hydrolysates

To identify and overcome key barriers to sustainable conversion of lignocellulosic biomass to biofuels, we employed multiomic approaches to investigate the effects of lignocellulosic hydrolysates on the physiology and gene regulation in an Escherichia coli ethanologen.  We generated synthetic hydrolysate (SynHv3), which contains acetate/acetamide, extra sugars, higher osmolarity, osmoprotectants, and potential lignin-derived inhibitors (phenolic lignotoxins or LT) at the concentrations detected in the authentic hydrolysate prepared from AFEX-pretreated corn stover (ACSH). Comparative multiomic fermentations with ACSH and SynHv3 in the presence or absence of lignotoxins (LT) were performed, and samples were collected for gene expression (Microarray and RNAseq), metabolomic and proteomic analyses. Preliminary data analyses revealed the effects of multiple inhibitors and stress responses in ASCH and SynH+LT on cell growth, ethanol synthesis, and xylose conversion. Furthermore, we also found that the phenolic amides (feruloyl amide and coumaroyl amide) were the principal inhibitors of E. coli growth and xylose utilization. More detailed comparative multiomic data analyses will be presented and discussed.