Department of Biotechnology and Food Microbiology, Wrocław University of Environmental and Life Sciences, 37 Chełmońskiego Street, 51-630, Wrocław, Poland.
Laboratory for Biosustainability, Institute of Environmental Biology, Wrocław University of Environmental and Life Sciences, Wrocław, Poland.
Microb Cell Fact. 2022 Oct 28;21(1):226. doi: 10.1186/s12934-022-01951-w.
The utilization of industrial wastes as feedstock in microbial-based processes is a one of the high-potential approach for the development of sustainable, environmentally beneficial and valuable bioproduction, inter alia, lipids. Rye straw hydrolysate, a possible renewable carbon source for bioconversion, contains a large amount of xylose, inaccessible to the wild-type Yarrowia lipolytica strains. Although these oleaginous yeasts possesses all crucial genes for xylose utilization, it is necessary to induce their metabolic pathway for efficient growth on xylose and mixed sugars from agricultural wastes. Either way, biotechnological production of single cell oils (SCO) from lignocellulosic hydrolysate requires yeast genome modification or adaptation to a suboptimal environment.
The presented Y. lipolytica strain was developed using minimal genome modification-overexpression of endogenous xylitol dehydrogenase (XDH) and xylulose kinase (XK) genes was sufficient to allow yeast to grow on xylose as a sole carbon source. Diacylglycerol acyltransferase (DGA1) expression remained stable and provided lipid overproduction. Obtained an engineered Y. lipolytica strain produced 5.51 g/L biomass and 2.19 g/L lipids from nitrogen-supplemented rye straw hydrolysate, which represents an increase of 64% and an almost 10 times higher level, respectively, compared to the wild type (WT) strain. Glucose and xylose were depleted after 120 h of fermentation. No increase in byproducts such as xylitol was observed.
Xylose-rich rye straw hydrolysate was exploited efficiently for the benefit of production of lipids. This study indicates that it is possible to fine-tune a newly strain with as minimally genetic changes as possible by adjusting to an unfavorable environment, thus limiting multi-level genome modification. It is documented here the use of Y. lipolytica as a microbial cell factory for lipid synthesis from rye straw hydrolysate as a low-cost feedstock.
将工业废料作为微生物过程的原料利用是开发可持续、环境友好和有价值的生物生产（包括脂质）的高潜力方法之一。黑麦秸秆水解物是生物转化的一种可再生碳源，含有大量木糖，无法被野生型 Yarrowia lipolytica 菌株利用。尽管这些产油酵母拥有利用木糖的所有关键基因，但有必要诱导其代谢途径，以使其能够有效利用木糖和农业废料中的混合糖进行生长。无论是哪种方式，从木质纤维素水解物中生物技术生产单细胞油（SCO）都需要酵母基因组修饰或适应次优环境。
本研究开发的 Yarrowia lipolytica 菌株采用最小基因组修饰-过表达内源性木糖醇脱氢酶（XDH）和木酮糖激酶（XK）基因，足以使酵母能够以木糖为唯一碳源生长。二酰基甘油酰基转移酶（DGA1）的表达保持稳定，并提供了脂质的过量生产。获得的工程化 Yarrowia lipolytica 菌株从添加氮的黑麦秸秆水解物中生产 5.51g/L 生物质和 2.19g/L 脂质，与野生型（WT）菌株相比，分别提高了 64%和近 10 倍。葡萄糖和木糖在 120h 发酵后耗尽。没有观察到副产物如木糖醇的增加。
富含木糖的黑麦秸秆水解物被有效地利用，有利于脂质的生产。本研究表明，可以通过调整到不利的环境，对新菌株进行尽可能小的遗传改变进行微调，从而限制多层次的基因组修饰。本文记录了使用 Yarrowia lipolytica 作为微生物细胞工厂，从黑麦秸秆水解物作为低成本饲料合成脂质。
