Genetic Engineering of Inhibitor-Tolerant Saccharomyces cerevisiae for Improved Xylose Utilization in Ethanol Production
Genetic Engineering of Inhibitor-Tolerant Saccharomyces cerevisiae for Improved Xylose Utilization in Ethanol Production
复制标题
DOI：
10.1007/s12155-011-9176-9
复制
发表时间：
2012-06-01
影响因子：
3.6
通讯作者：
Moon, Jaewoong
中科院分区：
文献类型：
--
作者：
Ma, Menggen;Liu, Z. Lewis;Moon, Jaewoong
为了经济地生产木质纤维素至乙醇，理想的生物催化剂应耐受源自木质纤维素预处理的抑制剂，并能够利用己糖和戊糖的异质生物质糖。此前，我们开发了一种耐抑制剂的酿酒酵母菌株 NRRL Y-50049，它能够原位解毒常见的醛抑制剂，如 2-糠醛（糠醛）和 5-（羟甲基）-2-糠醛（HMF）。在这项研究中，我们对 Y-50049 进行了基因改造，以启用并增强其木糖利用能力。合成了密码子优化的酵母木糖异构酶基因 (YXI)，并将其引入到 Y-50049 的确定染色体位点中。两个新鉴定的木糖转运相关基因 XUT4 和 XUT6，以及先前报道的来自树干酵母的木酮糖激酶基因 (XKS1) 和木糖醇脱氢酶基因 (XYL2) 也被工程化到酵母中，产生菌株 NRRL Y-50463。该工程菌株能够以木糖作为唯一碳源生长，并在糠醛和HMF存在下对葡萄糖和木糖的混合糖进行厌氧发酵，获得最低38.6 g l(-1)的乙醇产量。
For economical lignocellulose-to-ethanol production, a desirable biocatalyst should tolerate inhibitors derived from preteatment of lignocellulose and be able to utilize heterogeneous biomass sugars of hexoses and pentoses. Previously, we developed an inhibitor-tolerant Saccharomyces cerevisiae strain NRRL Y-50049 that is able to in situ detoxify common aldehyde inhibitors such as 2-furaldehyde (furfural) and 5-(hydroxymethyl)-2-furaldehyde (HMF). In this study, we genetically engineered Y-50049 to enable and enhance its xylose utilization capability. A codon-optimized xylose isomerase gene for yeast (YXI) was synthesized and introduced into a defined chromosomal locus of Y-50049. Two newly identified xylose transport related genes XUT4 and XUT6, and previously reported xylulokinase gene (XKS1), and xylitol dehydrogenase gene (XYL2) from Scheffersomyces stipitis were also engineered into the yeast resulting in strain NRRL Y-50463. The engineered strain was able to grow on xylose as sole carbon source and a minimum ethanol production of 38.6 g l(-1) was obtained in an anaerobic fermentation on mixed sugars of glucose and xylose in the presence of furfural and HMF.