抗氧化基因过表达提高运动发酵单胞菌糠醛耐受性  

Enhanced Furfural Tolerance in Zymomonas mobilis by the Overexpression of Antioxidant Genes

作　　者：闻远 夏娟[1] 戚良华 刘小伟 刘晨光[1] 白凤武[1] WEN Yuan;XIA Juan;QI Liang-hua;LIU Xiao-wei;LIU Chen-guang;BAI Feng-wu(State Key Laboratory of Microbial Metabolism,School of Life Sciences and Biotechnology,Shanghai Jiao Tong University,Shanghai 200240;Shanghai Baoxing Bio-engineering Equipment Co. Ltd.,Shanghai 201404)

机构地区：[1]微生物代谢国家重点实验室上海交通大学生命科学技术学院,上海200240 [2]上海保兴生物设备工程有限公司,上海201404

出　　处：《生物技术通报》2019年第8期85-94,共10页Biotechnology Bulletin

基　　金：国家自然科学基金项目(21536006);上海市自然科学基金项目(18ZR1420700);上海市闵行区科技项目(2017MH294)

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2g/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。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.

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 

分 类 号：TQ920.6[轻工技术与工程—发酵工程] TQ251.11