Shan Chengpeng, Xia Tianqing, Liu Jiao, Wang Ying, Bai Penggang, Xu Lili, Li Zailu, Zhao Jianzhi, Bao Xiaoming
State Key Laboratory of Biobased Material and Green Papermaking, School of Bioengineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250353, Shandong, People's Republic of China.
Shandong Shouguang Juneng Golden Corn Co., Ltd, Shouguang, 262711, Shandong, People's Republic of China.
Bioresour Bioprocess. 2023 Jul 22;10(1):41. doi: 10.1186/s40643-023-00661-4.
A suitable nutrient supply, especially of vitamins, is very significant for the deep display of the inherent genetic properties of microorganisms. Here, using the chemically defined minimal medium (MM) for yeast, nicotinamide and inositol were confirmed to be more beneficial for the performance of two industrial baker's yeasts, a conventional and a high-sugar-tolerant strain. Increasing nicotinamide or inositol to proper levels could enhance the both strains on cell growth and activity and product performance, including trehalose accumulation and leavening performance. The activity of key enzymes (PCK, TPS) and the content of intermediate metabolites (G6P, UDPG) in the trehalose synthesis pathway were promoted by a moderate supply of nicotinamide and inositol. That were also proved that an appropriate amount of niacinamide promoted the transcription of longevity-related genes (PNC1, SIR2), and the proper concentration of inositol altered the phospholipid composition in cells, namely, phosphatidylinositol and phosphatidyl choline. Furthermore, the cell growth and the leavening performance of the both strains were promoted after adjusting inositol to choline to the proper ratio, resulting directly in content changes of phosphatidylinositol and phosphatidyl choline in the cells. While the two strains responded to the different proper ratio of inositol to choline probably due to their specific physiological characteristics. Such beneficial effects of increased nicotinamide levels were confirmed in natural media, molasses and corn starch hydrolyzed sugar media. Meanwhile, such adjustment of inositol to choline ratio could lessen the inhibition of excess inositol on cell growth of the two tested strains in corn starch hydrolyzed sugar media. However, in molasse, such phenomenon was not observed probably since there was higher Ca in it. The results indicated that the effects of nutrient factors, such as vitamins, on cell growth and other properties found out from the simple chemically defined minimal medium were an effective measure to use in improving the recipe of natural media at least for baker's yeast.
合适的营养供应，尤其是维生素供应，对于微生物固有遗传特性的充分展现非常重要。在此，使用酵母化学限定基本培养基（MM），证实烟酰胺和肌醇对两种工业面包酵母（一种传统菌株和一种高糖耐受菌株）的性能更有益。将烟酰胺或肌醇增加到适当水平可增强两种菌株的细胞生长、活性及产品性能，包括海藻糖积累和发酵性能。适度供应烟酰胺和肌醇可促进海藻糖合成途径中关键酶（PCK、TPS）的活性及中间代谢物（G6P、UDPG）的含量。还证明适量的烟酰胺促进了长寿相关基因（PNC1、SIR2）的转录，适当浓度的肌醇改变了细胞中的磷脂组成，即磷脂酰肌醇和磷脂酰胆碱。此外，将肌醇与胆碱调整到适当比例后，两种菌株的细胞生长和发酵性能均得到促进，直接导致细胞中磷脂酰肌醇和磷脂酰胆碱含量的变化。而两种菌株可能因其特定生理特性对肌醇与胆碱的不同适当比例有不同反应。烟酰胺水平升高的这种有益效果在天然培养基、糖蜜和玉米淀粉水解糖培养基中得到证实。同时，在玉米淀粉水解糖培养基中，这种肌醇与胆碱比例的调整可减轻过量肌醇对两种受试菌株细胞生长的抑制。然而，在糖蜜中未观察到这种现象，可能是因为其中钙含量较高。结果表明，从简单的化学限定基本培养基中发现的营养因子如维生素对细胞生长和其他特性的影响，至少对于面包酵母而言，是用于改进天然培养基配方的有效措施。
