丙丁梭菌/酿酒酵母混合培养耦联乙酸外添强化丙酮合成─侧重LCA的ABE发酵

Enhancing Acetone Synthesis by Co-culturing C. acetobutylicum/S. cerevisiae Integrated with Exogenous Acetate Addition: Life Cycle Assessment Emphasized ABE Fermentation

摘要:

提出梭菌/酵母混合培养耦联乙酸外添体系强化丙酮合成的ABE发酵新策略，可以同时强化丁醇特别是丙酮的合成。与对照组相比，外添化学合成乙酸时，丁醇、丙酮质量浓度和丙酮/丁醇质量比分别达到13.91 g/L、8.27 g/L和0.59，增幅分别为19.6%、41.1%和18.0%；外添廉价的乙酸发酵上清液时，相应的发酵指标达到14.23 g/L、8.55 g/L和0.60，增幅分别为22.4%、46.0%和20.0%，发酵原料成本降低、丙酮发酵生产的可行性提高。结果表明，该发酵策略可刺激有利于梭菌生存和丁醇合成的4种氨基酸的分泌；可以在保证丁醇正常合成的前提下，适度抑制NADH再生、降低细胞能量周转、强化丙酮生物合成，进而显著改善了ABE发酵性能。

Abstract:

Proposed a novel fermentation strategy of co-culturing C. acetobutylicum/S. cerevisiae integrated with exogenous acetate addition, to enhance acetone and butanol productions simultaneously. Compared with control group, concentrations of butanol and acetone, as well as acetone/butanol ratio reached high levels of 13.91 g/L, 8.27 g/L and 0.59, respectively; with the increments of 19.6%, 41.1% and 18.0%, when adding the synthetic acetate. On the other hand, the relevant fermentation indexes also reached 14.23 g/L, 8.55 g/L and 0.60, respectively, with the increments of 22.4%, 46.0% and 20.0%, when directly adding the cheaper acetate fermentative supernatant, resulting a reduced raw materials cost and enhanced industrial ABE fermentation feasibility. Results show that the proposed strategy could stimulate secretions of the four amino acids, which were beneficial for C. acetobutylicum survival and butanol synthesis; moderately repress NADH regeneration and reduce the cellular energy load. These led to an enhanced acetone synthesis but without sacrificing butanol production, and entire ABE fermentation performance was significantly improved.