Monday, November 4, 2013
Capri Ballroom (Marriott Marco Island)
To identify and overcome key barriers to sustainable conversion of lignocellulosic biomass to biofuels, multiomic approaches were employed to investigate the effects of lignocellulosic hydrolysates on the physiology and gene regulation in ethanologen Escherichia coli. Based on the chemical analysis of hydrolysate prepared from AFEX-pretreated corn stover (ACSH), we generated a chemical-defined synthetic hydrolysate (SynH), containing potential inhibitors, such as phenolic compounds (lignotoxins), acids, as well as osmoprotectants found in ACSH. Comparative multiomic fermentations with ACSH and SynH were performed, and samples were collected for end product analysis, gene expression (Microarray and RNAseq), and metabolomic and proteomic analyses. Comparative multiomic data analysis revealed the stress response of ethanologen in ACSH and SynH, especially in the presence lignin-derived inhibitors (phenolic lignotoxins or LT). Specifically, we found that two most abundant phenolic amides in ACSH (feruloyl amide and coumaroyl amide) were the principal inhibitors of cell growth and xylose utilization in E. coli. We also investigated the inhibitory mechanism of LT on xylose utilization by comparative fermentation with SynH containing different sugars. Our results showed that SynH provide genetics, evolution, and systems biology with flexible and reproducible conditions.