He Yanyan, Zi Lihan, Zhang Baohui, Xu Jianren, Wang Dandan, Bai Fengwu
School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, Liaoning, China.
State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
Sheng Wu Gong Cheng Xue Bao. 2018 Jun 25;34(6):906-915. doi: 10.13345/j.cjb.170476.
By-products released from pretreatment process of lignocellulose seriously hinder the development of cellulosic fuel ethanol. Therefore, the great way to increase the efficiency of cellulosic ethanol production is improvement of Saccharomyces cerevisiae tolerance to these inhibitors. In this work, the effects of LCB4 gene overexpression on cell growth and ethanol fermentation in S. cerevisiae S288C under acetic acid, furfural and vanillin stresses were studied. Compared to the control strain S288C-HO, the recombinant strain S288C-LCB4 grew better on YPD solid medium containing 10 g/L acetic acid, 1.5 g/L furfural and 1 g/L vanillin. Ethanol yields of recombinant strain S288C-LCB4 were 0.85 g/(L·h), 0.76 g/(L·h) and 1.12 g/(L·h) when 10 g/L acetic acid, 3 g/L furfural and 2 g/L vanillin were supplemented into the fermentation medium respectively, which increased by 34.9%, 85.4% and 330.8% than the control strain S288C-HO. Meanwhile, ethanol fermentation time was reduced by 30 h and 44 h under furfural and vanillin stresses respectively. Further metabolites analysis in fermentation broth showed that the recombinant strain produced more protective compounds, such as glycerol, trehalose and succinic acid, than the control strain, which could be the reason for enhancing strain tolerance to these inhibitors from pretreatment process of lignocellulose. The results indicated that overexpression of LCB4 gene could significantly improve ethanol fermentation in S. cerevisiae S288C under acetic acid, furfural and vanillin stresses.
木质纤维素预处理过程中释放的副产物严重阻碍了纤维素燃料乙醇的发展。因此，提高纤维素乙醇生产效率的有效方法是提高酿酒酵母对这些抑制剂的耐受性。在本研究中，研究了LCB4基因过表达对酿酒酵母S288C在乙酸、糠醛和香草醛胁迫下细胞生长和乙醇发酵的影响。与对照菌株S288C-HO相比，重组菌株S288C-LCB4在含有10 g/L乙酸、1.5 g/L糠醛和1 g/L香草醛的YPD固体培养基上生长得更好。当分别向发酵培养基中添加10 g/L乙酸、3 g/L糠醛和2 g/L香草醛时，重组菌株S288C-LCB4的乙醇产量分别为0.85 g/(L·h)、0.76 g/(L·h)和1.12 g/(L·h)，比对照菌株S288C-HO分别提高了34.9%、85.4%和330.8%。同时，在糠醛和香草醛胁迫下，乙醇发酵时间分别缩短了30 h和44 h。发酵液的进一步代谢产物分析表明，重组菌株比对照菌株产生了更多的保护性化合物，如甘油、海藻糖和琥珀酸，这可能是增强菌株对木质纤维素预处理过程中这些抑制剂耐受性的原因。结果表明，LCB4基因的过表达可以显著提高酿酒酵母S288C在乙酸、糠醛和香草醛胁迫下的乙醇发酵能力。
