抗氧化基因过表达提高运动发酵单胞菌糠醛耐受性

doi:10.13560/j.cnki.biotech.bull.1985.2019-0040

摘要/Abstract

摘要： 糠醛是木质纤维素水解液的主要抑制物,能诱发活性氧自由基（Reactive oxygen species,ROS）产生。探索抗氧化基因对于糠醛耐受性的影响有助于改善菌株表型。过表达运动发酵单胞菌Zymomonas mobilis 自身的NADH氧化酶（ZMO1885）、NADP⁺还原酶（ZMO1753）和谷胱甘肽还原酶（ZMO1211）基因,检测胞内ROS、NADH/NAD⁺以及其耐受性能。结果表明,在2 g/L糠醛条件下,相比对照菌株,ZM4/ZMO1885的胞内ROS降低了52.1%,生物量提高了38.9%,且未引起胞内辅因子扰动。过表达ZMO1753和 ZMO1211没有显著提高菌株耐受性。在模拟木质纤维素水解液中,ZM4/ZMO1885的生物量较对照菌株提高了46.9%,糖耗速率提高了110.3%,乙醇生产力提高了195.2%。综上,过表达抗氧化酶基因能够影响糠醛胁迫耐受性,其中过表达ZMO1885不仅不影响细胞正常生长,还能降低ROS水平,提高糠醛去除率,改善了细胞的糠醛耐受性。

关键词: 糠醛, 活性氧自由基, NADH氧化酶, 谷胱甘肽还原酶, NADP⁺还原酶, 耐受性

Abstract: Furfural is a major inhibitor in lignocellulosic hydrolysate,which induces the generation of reactive oxygen species（ROS）. Exploration of relationships between antioxidant genes and furfural tolerance contributes to enhanced tolerance performance of strains. ;By overexpressing endogenous antioxidant genes NADH oxidase（ZMO1885）,NADP⁺ reductase（ZMO1753）,and glutathione reductase（ZMO1211）in Zymomonas mobilis,tolerance performance,ROS,and NADH/NAD⁺were measured. The results suggested that overexpression of ZM4 ZMO1885 reduced the intracellular ROS level by 52.1%,increased the biomass by 38.9%,and improved furfural tolerance of ZM4/ZMO1885 with no significant interference of cellular NADH/NAD⁺ in the medium containing 2 g/L furfural,compared to the control. However,recombinant strain ZM4/ZMO1753 and ZM4/ZMO1211 did not demonstrate significantly elevated furfural tolerance. In the simulated lignocellulosic hydrolysate,the biomass of ZM4/ZMO1885 was 46.9% higher than that of the control strain,and the sugar consumption rate increased by 110.3% with the increased ethanol productivity by 195.2%. Collectively,the overexpression of antioxidant genes affects furfural tolerance performance,among which ZMO1885 overexpression improves furfural tolerance through promoting ROS elimination and intracellular furfural conversion without redox level perturbation.

Key words: furfural, reactive oxygen species, NADH oxidase, glutathione reductase, NADP⁺ reductase, tolerance

闻远, 夏娟, 戚良华, 刘小伟, 刘晨光, 白凤武. 抗氧化基因过表达提高运动发酵单胞菌糠醛耐受性[J]. 生物技术通报, 2019, 35(8): 85-94.

WEN Yuan, XIA Juan, QI Liang-hua, LIU Xiao-wei, LIU Chen-guang, BAI Feng-wu. Enhanced Furfural Tolerance in Zymomonas mobilis by the Overexpression of Antioxidant Genes[J]. Biotechnology Bulletin, 2019, 35(8): 85-94.

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