Increased Tolerance to Furfural by Introduction of Polyhydroxybutyrate Synthetic Genes to Escherichia coli

: Polyhydroxybutyrate (PHB), the most well-known polyhydroxyalkanoate, is a bio-based, biodegradable polymer that has the potential to replace petroleum-based plastics. Lignocellulose hydrolysate, a non-edible resource, is a promising substrate for the sustainable, fermentative production of PHB. However, its application is limited by the generation of inhibitors during the pretreatment processes. In this study, we investigated the feasibility of PHB production in E. coli in the presence of inhibitors found in lignocellulose hydrolysates. Our results show that the introduction of PHB synthetic genes (bktB, phaB, and phaC from Ralstonia eutropha H16) improved cell growth in the presence of the inhibitors such as furfural, 4-hydroxybenzaldehyde, and vanillin, suggesting that PHB synthetic genes confer resistance to these inhibitors. In addition, increased PHB production was observed in the presence of furfural as opposed to the absence of furfural, suggesting that this compound could be used to stimulate PHB production. Our findings indicate that PHB production using lignocellulose hydrolysates in recombinant E. coli could be an innovative strategy for cost-effective PHB production, and PHB could be a good target product from lignocellulose hydrolysates, especially glucose.