敲除REG1同时过表达SNF1基因对工业面包酵母不加糖面团发酵的影响

Effect of REG1 Deletion with SNF1 Overexpression on the Fermentation of Industrial Baker’s Yeast in Lean Dough

摘要:

研究了蛋白磷酸酶PP1调节亚基编码基因REG1缺失同时蛋白激酶基因SNF1过表达对工业面包酵母麦芽糖代谢和不加糖面团发酵的影响。比较分析REG1缺失同时SNF1过表达转化子BYKPS-R和亲本菌株BY14α、REG1缺失突变株BYK-R的MAL基因mRNA水平、麦芽糖酶和麦芽糖通透酶活力、麦芽糖代谢水平、不加糖面团发酵力，以及基本生长性能，结果表明，敲除REG1同时过表达SNF1能够显著提高麦芽糖代谢相关基因转录和酶活力，有效减弱葡萄糖阻遏，从而使面包酵母的麦芽糖消耗速率（葡萄糖被完全消耗完之前）较BY14α和BYK-R分别提高了18.59%和4.40%，不加糖面团发酵力分别提高了12.51%和3.22%。在REG1基因缺失的基础上，过表达SNF1可以进一步提高面包酵母的麦芽糖代谢和不加糖面团发酵水平，同时不影响面包酵母菌株生长性能，因此转化子BYKPS-R具备潜在的工业应用价值，同时该研究为快速发酵面包酵母菌株的选育奠定基础。

Abstract:

The effects of REG1 (regulatory subunits of protein phosphatase type 1 PP1) deletion with protein kinase gene SNF1 overexpression on the maltose metabolism and lean dough fermentation by industrial baker’s yeast were investigated by analysis of the MAL mRNA expression, maltase and maltose permease activities, maltose metabolism and leavening ability in lean dough. The basic growth characteristics of REG1 deletion with SNF1 overexpression strain BYKPS-R, the parental strain BY14α, and the REG1 deletion strain BYK-R were also studied. REG1 deletion with SNF1 overexpression had significant effects on increasing MAL gene expression and enzyme activity, and relieving glucose repression, thereby enhancing the maltose utilization efficiency (increase of 18.59% and 4.40% compared with the strains BY14α and BYK-R, respectively, at the point of glucose exhaustion), and lean dough leavening ability (12.51% and 3.22% increases compared with the strains BY14α and BYK-R, respectively). On the background of REG1 deletion, overexpression of SNF1 further improved maltose metabolism and leavening ability of industrial baker’s yeast in lean dough. Moreover, overexpression of SNF1 did not affect growth in REG1 deleted yeast. This strain has potential for application. This study lays a foundation for the breeding of fast-fermenting baker’s yeast.