Identification of genes involved in xylose metabolism of Meyerozyma guilliermondii and their genetic engineering for increased xylitol production
Identification of genes involved in xylose metabolism of Meyerozyma guilliermondii and their genetic engineering for increased xylitol production
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DOI：
10.1186/s13568-020-01012-8
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发表时间：
2020-04-20
期刊：
影响因子：
3.7
通讯作者：
Zwirzitz, Alexander
中科院分区：
文献类型：
--
作者：
Atzmueller, Denise;Ullmann, Nadine;Zwirzitz, Alexander
Meyerozyma guilliermondii是一种天然同化木糖的非常规酵母，被认为是利用生物技术生产糖替代品木糖醇的候选者。由于木糖代谢的基因尚不清楚，因此迄今为止所发表的提高该酵母的木糖醇产量的所有努力都限于发酵优化。因此，这项研究旨在首次对这种生物进行基因工程改造，以增加木糖醇的产量。因此，以前未鉴定的M.通过途径研究和序列相似性分析，鉴定了编码木糖还原酶（XR）和木糖醇脱氢酶（XDH）的季也蒙氏菌ATCC 6260。推定XR的克隆和过表达以及推定XDH基因的敲除产生木糖醇产量增加约三倍的菌株。结合两种遗传修饰的菌株显示木糖醇总产量增加了五倍。用XR过表达和XDH敲除菌株的裂解物进行的酶活性测定强调了各自基因的推定功能。此外，工程菌株在木糖作为唯一碳源上的生长评价提供了对木糖代谢及其用于细胞生长的见解。
Meyerozyma guilliermondii, a non-conventional yeast that naturally assimilates xylose, is considered as a candidate for biotechnological production of the sugar alternative xylitol. Because the genes of the xylose metabolism were yet unknown, all efforts published so far to increase the xylitol yield of this yeast are limited to fermentation optimization. Hence, this study aimed to genetically engineer this organism for the first time with the objective to increase xylitol production. Therefore, the previously uncharacterized genes of M. guilliermondii ATCC 6260 encoding for xylose reductase (XR) and xylitol dehydrogenase (XDH) were identified by pathway investigations and sequence similarity analysis. Cloning and overexpression of the putative XR as well as knockout of the putative XDH genes generated strains with about threefold increased xylitol yield. Strains that combined both genetic modifications displayed fivefold increase in overall xylitol yield. Enzymatic activity assays with lysates of XR overexpressing and XDH knockout strains underlined the presumed functions of the respective genes. Furthermore, growth evaluation of the engineered strains on xylose as sole carbon source provides insights into xylose metabolism and its utilization for cell growth.