Efficient acetone–butanol–ethanol (ABE) production by a butanol-tolerant mutant of Clostridium beijerinckii in a fermentation–pervaporation coupled process

• Mutants with high butanol tolerance were obtained by ARTP mutagenesis.
• Enhanced ABE production of 18.8 g/L was achieved during batch fermentation.
• Butanol-tolerant mutant was first applied to PV coupled ABE fermentation.
• ABE productivity was significantly improved by using BT14 and pervaporation.

Butanol inhibition is one of the major obstacles limiting the economic viability of acetone–butanol–ethanol (ABE) fermentation. In this study, a butanol-tolerant mutant (Clostridium beijerinckii BT14) was generated by atmospheric and room temperature plasmas (ARTP). This mutant showed significant advantage over its parent strain in terms of butanol tolerance. Compared to its parent strain, batch fermentation by this mutant produced 25% higher butanol and 33% higher ABE solvents due to its efficient generation of intracellular NADH and high NADH-dependent butanol dehydrogenase activity. Furthermore, C. beijerinckii BT14 was applied to fed-batch fermentation with pervaporation (PV). As a results, C. beijerinckii BT14 grew to a high cell density and this process generated highly concentrated ABE solution with a high solvent productivity of 0.98 g/(L h) and glucose consumption rate of 2.64 g/(L h). Thus, this work provides an appropriate strategy to develop an efficient process for ABE production in the PV coupled fermentation.