Being the most abundant renewable organic substance on Earth, lignocellulosic biomass has acted as an attractive and cost-effective feedstock for biobased production of value-added products. However, lignocellulosic biomass should be properly treated for its effective utilization during biotransformation. The current work aimed to demonstrate biobased production of butyrate and 3-hydroxybutyrate (3-HB) in engineered Escherichia coli using pretreated and detoxified aspen tree (Populus tremuloides) wood chips as the feedstock. Various bioprocessing and genetic/metabolic factors limiting the production of cellulosic butyrate and 3-HB were identified. With these developed bioprocessing strategies and strain engineering approaches, major carbons in the hydrolysate, including glucose, xylose, and even acetate, could be completely dissimilated during shake-flask cultivation with up to 1.68 g L-1 butyrate, 8.95 g L-1 3-HB, and minimal side metabolites (i.e., acetate and ethanol) being obtained. Our results highlight the importance of consolidating bioprocess and genetic engineering strategies for effective biobased production from lignocellulosic biomass.
Keywords: 3-Hydroxybutyrate; Butyrate; Detoxification; Escherichia coli; Lignocellulosic hydrolysate; Over-liming.