Cellulosic ethanol production via consolidated bioprocessing at 75 °C by engineered Caldicellulosiruptor bescii

摘要

BackgroundThe C. bescii genome does not encode an acetaldehyde/alcohol dehydrogenase or an acetaldehyde dehydrogenase and no ethanol production is detected in this strain. The recent introduction of an NADH-dependent AdhE from C. thermocellum (Fig. a) in an ldh mutant of this strain resulted in production of ethanol from un-pretreated switchgrass, but the thermolability of the C. thermocellum AdhE at the optimum growth temperature of C. bescii (78 °C) meant that ethanol was not produced above 65 °C.Proposed scheme for the pyruvate to ethanol pathway in C. thermocellum and T. pseudethanolicus 39E. >a The C. thermocellum ethanol pathway. The red colored AdhE (Cthe_0423) is already expressed and tested in C. bescii []. >b The T. pseudethanolicus 39E ethanol pathway. The green colored AdhE (Teth39_0206) and blue colored AdhB (Teth39_0218) are expressed and tested in C. bescii in this study