钙转运蛋白Gdt1过表达对酿酒酵母蛋白酶A胞外分泌的影响  

Effect of Gdt1 overexpression on secretion of Saccharomyces cerevisiae proteinase A

作　　者：宋露露 刘小航 郭学武[1,2] 陈叶福[1,2] 肖冬光[1,2] SONG Lulu;LIU Xiaohang;GUO Xuewu;CHEN Yefu;XIAO Dongguang(Key Laboratory of Industrial Fermentation Microbiology,Ministry of Education,Tianjin University of Science and Technology,Tianjin 300457,China;College of Bioengineering,Tianjin University of Science and Technology,Tianjin 300457,China)

机构地区：[1]工业发酵微生物教育部重点实验室(天津科技大学),天津300457 [2]天津科技大学生物工程学院,天津300457

出　　处：《食品与发酵工业》2020年第9期10-17,共8页Food and Fermentation Industries

基　　金：国家自然科学基金项目(31271916)。

摘　　要：啤酒泡沫稳定性是评估啤酒质量的一个关键因素,发酵液中的蛋白酶A会影响啤酒的泡沫稳定性。通过过表达钙转运蛋白Gdt1促进蛋白酶A的液泡分选的方法,达到减弱酿酒酵母向细胞外分泌蛋白酶A的目的。以酿酒酵母菌株W303-1A为亲本菌株,通过同源重组依赖型DNA装配方法构建Gdt1过表达菌株,然后将Gdt1过表达菌株和亲本菌株在相同的低氮胁迫条件下进行发酵,测定其胞内外的蛋白酶A活力以及基本发酵性能。研究结果表明:发酵结束时,Gdt1过表达菌株的胞内蛋白酶A活力较亲本菌株提高了12.59%,胞外蛋白酶A活力较亲本菌株降低了18.81%;同时,过表达Gdt1没有影响菌株的基本发酵性能。研究揭示了一种有效的降低蛋白酶A的胞外分泌的方法,为筛选低蛋白酶A胞外分泌菌株提供了理论参考。Beer foam stability, a key factor in assessing overall beer quality, is affected by proteinase A(PrA) in the fermentation broth. To weaken PrA excretion from Saccharomyces cerevisiae, the vacuolar sorting of PrA was strengthened by overexpression of Ca2+ transporter Gdt1. S. cerevisiae W303-1 A was used as the parental strain, and Gdt1-overexpression strain was constructed by exploiting the in vivo homologous recombination-dependent DNA assembler. Fermentation experiments for the Gdt1-overexpression strain and the parental strain were performed under nitrogen-deficient condition, and PrA activity, and fermentation performance of the two strains were examined. Results showed that the intracellular PrA activities of the Gdt1-overexpression strain were increased by 12.59% and the extracellular PrA activities were decreased by 18.81% at the end of fermentation compared with those of the parental strain. Meanwhile, no obvious differences were found on the fermentation performance of the two strains. The research uncovers an effective method to decrease the extracellular secretion of S. cerevisiae PrA, which provides a theoretical reference for the screening of low-PrA-activity strains.

关 键 词：啤酒泡沫 蛋白酶A Gdt1 液泡分选 胞外分泌 

分 类 号：TS262.5[轻工技术与工程—发酵工程]