絮凝特性对自絮凝颗粒酵母耐酒精能力的影响及作用机制  

Effect of Flocculence of a Self-flocculating Yeast on its Tolerance to Ethanol and the Mechanism

作　　者：胡纯铿[1] 白凤武[2] 安利佳[2] 

机构地区：[1]华侨大学生物工程与技术系,泉州362011 [2]大连理工大学生物科学与工程系,大连116024

出　　处：《生物工程学报》2005年第1期123-128,共6页Chinese Journal of Biotechnology

基　　金：国家高技术研究发展计划项目 (No .2 0 0 2AA64 70 60 )资助。~~

摘　　要：首次报道絮凝特性提高酵母菌耐酒精能力的现象及其机制。融合株SPSC与其两亲本粟酒裂殖酵母变异株和酿酒酵母变异株于 30℃经 18% (V V)酒精冲击 7h的存活率分别为 5 2 %、37%和 9%。细胞膜磷脂脂肪酸组成分析表明 ,两絮凝酵母 (融合株SPSC和粟酒裂殖酵母变异株 )的棕榈酸含量均约为非絮凝酵母 (酿酒酵母变异株 )的两倍 ,而棕榈油酸和油酸的含量明显低于后者。研究表明 ,当两絮凝酵母在培养中由于柠檬酸钠的作用 (抑制絮凝体的形成 )而以游离细胞生长存在时 ,其细胞膜磷脂棕榈酸含量显著下降 ,而棕榈油酸和油酸的含量明显增加 ,结果细胞膜磷脂脂肪酸组成特点与酿酒酵母变异株相似 ;而且实验表明 ,絮凝特性的消失伴随菌体耐酒精能力的急剧下降 ,变得与酿酒酵母变异株的水平相当。这些结果提示两絮凝酵母具有较强的耐酒精能力与其细胞膜磷脂脂肪酸组成中含有更高比例的棕榈酸有关。Investigation was undertaken for the purpose of examining any possible correlation between flocculence of a self_flocculating fusant of Schizosaccharomyces pombe mutant and Saccharomyces cerevisiae mutant (called fusant SPSC for short) and the tolerance of this strain to ethanol. When exposed to 18% ( V/V ) ethanol for 7 h at 30℃, 52%, 37% and 9% of viability levels remained for the cells of fusant SPSC and its two parental strains, Sch. pombe mutant and S. cerevisiae mutant respectively. Analysis of phospholipid fatty acid composition of plasma membrane showed that the content of palmitic acid of each flocculating yeast (fusant SPSC or Sch. pombe mutant) was around 2_fold higher than that of free S. cerevisiae mutant, with remarkably lower contents of palmitoleic and oleic acids than the latter. When 0 1 mol/L sodium citrate was initially included in the medium in which cells of each flocculating yeast were grown, free cells rather than aggregates were finally obtained. Furthermore, the content of palmitic acid in the phospholipid fatty acid composition of the plasma membranes of the free cells of each flocculating yeast was found to decrease significantly, with a marked increase in the contents of palmitoleic and oleic acids. As a result, the characteristics of the phospholipid fatty acid composition of the plasma membranes of the free cells of each flocculating yeast were similar to those of S. cerevisiae mutant. Meanwhile, the disappearance of flocculence of each flocculating yeast caused by the action of sodium citrate brought about a steeply decreased tolerance of the free cells to ethanol, thus being equivalent to that of S. cerevisiae mutant. These data suggest that the stronger ethanol tolerance of each flocculating yeast is related to the higher content of palmitic acid in the phospholipid fatty acid composition of the plasma membranes. Thus, the enhancement by flocculence on the tolerance of yeast cells to ethanol as well as its mechanism are first reported in this

关 键 词：耐酒精 絮凝特性 磷脂脂肪酸组成 

分 类 号：Q939.97[生物学—微生物学]