Division of Biotechnology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, P. R. China.
School of Biological Engineering, Dalian Polytechnic University, Dalian, P. R. China.
Biotechnol J. 2023 Apr;18(4):e2200510. doi: 10.1002/biot.202200510. Epub 2023 Feb 1.
Auxotrophic marker genes have been widely used for genetic engineering in yeast. However, the effects of amino acids or nucleotides deficiency in auxotrophic strains on cell growth and product synthesis were rarely reported. In this study, a total of eight auxotrophic strains of Saccharomyces cerevisiae with single knockout of selection markers were obtained. Cell growth and free fatty acid (FFA) production of these auxotrophic strains were evaluated with supplementation of different concentrations of amino acids or nucleotides. Generally, except ade2Δ mutants, most auxotrophic strains showed decreased cell growth and FFA production, which could be recovered by adding higher concentrations of supplements. LEU2 deletion (leu2Δ) damaged both cell growth and FFA production even with supplementation of 1000 mg L leucine. This study shows that growth and product biosynthesis of auxotrophs could be limited by insufficient supplementation of amino acids or nucleotides, and provides guidance on supplementation of these nutrients during fermentation to maximize cell growth and product biosynthesis.
营养缺陷型标记基因已广泛应用于酵母的基因工程。然而，营养缺陷型菌株中氨基酸或核苷酸缺乏对细胞生长和产物合成的影响却鲜有报道。本研究共获得了 8 株带有单一选择标记基因缺失的酿酒酵母营养缺陷型菌株。通过添加不同浓度的氨基酸或核苷酸来评估这些营养缺陷型菌株的细胞生长和游离脂肪酸（FFA）的生产情况。一般来说，除 ade2Δ 突变体外，大多数营养缺陷型菌株的细胞生长和 FFA 的生产能力均下降，添加较高浓度的补充剂可恢复其生长。即使添加 1000mg/L 的亮氨酸，LEU2 缺失（leu2Δ）也会同时破坏细胞生长和 FFA 的生产。本研究表明，氨基酸或核苷酸的补充不足会限制营养缺陷型菌株的生长和产物生物合成，为发酵过程中补充这些营养物质以最大程度地促进细胞生长和产物生物合成提供了指导。
