Department of Microbiology, Central University of Haryana, Mahendergarh, Haryana 123031, India.
Department of Marine Environmental Engineering, National Kaohsiung University of Science and Technology, Kaohsiung City 81157, Taiwan.
Bioresour Technol. 2022 Jan;344(Pt B):126247. doi: 10.1016/j.biortech.2021.126247. Epub 2021 Nov 2.
The present research work aimed at developing robust yeast cell factory via adaptive laboratory evolution (ALE) for improved cellulosic bioethanol production. Kluyveromyces marxianus JKH5, a newly isolated thermotolerant ethanologenic yeast, was engineered by serial passaging for 60 generations in medium supplemented with gradually higher concentration of inhibitors (acetic acid, furfural, and vanillin) that are generated during dilute acid pretreatment. The improved strain K. marxianus JKH5 C60, showed 3.3-fold higher specific growth rate, 56% reduced lag phase and 80% enhanced fermentation efficiency at 42 °C in comparison to parent strain in inhibitor cocktail comprising medium. Bioethanol production by simultaneous saccharification and fermentation of sequential dilute acid-alkali pretreated sugarcane bagasse in presence of inhibitors, resulted in ethanol titre and yield, respectively, 54.8 ± 0.9 g/L and 0.40 g/g. The adapted yeast can be used to ferment unwashed pretreated biomass, thereby, reducing overall cost, time, and wastewater generation, hence making bioethanol production sustainable.
本研究旨在通过适应性实验室进化（ALE）开发稳健的酵母细胞工厂，以提高纤维素生物乙醇的生产。新分离的耐热产乙醇酵母 Kluyveromyces marxianus JKH5 通过在补充有逐渐增加浓度抑制剂（在稀酸预处理过程中产生的乙酸、糠醛和香草醛）的培养基中连续传代 60 代进行工程改造。与亲本菌株相比，在含有培养基的抑制剂混合物中，改良菌株 K. marxianus JKH5 C60 的比生长速率提高了 3.3 倍，延迟期缩短了 56%，在 42°C 时发酵效率提高了 80%。在存在抑制剂的情况下，对顺序稀酸-碱预处理甘蔗渣进行同步糖化和发酵，乙醇得率和产率分别为 54.8±0.9 g/L 和 0.40 g/g。适应性酵母可用于发酵未经洗涤的预处理生物质，从而降低总成本、时间和废水生成，使生物乙醇生产可持续。
