一株特耐酸酵母R1的分离及其耐酸机理研究

Isolation and Preliminary Mechanism of Acid Tolerance of A Acidphilic Yeast Strain R1

从江西某铜矿的污泥中分离到一株特耐酸酵母菌R1(Rhodotorulasp .) ,能在pH值 1 5～ 6 0的范围内生长 ,最适生长pH为 3 0 ,属于嗜酸菌 ,初步鉴定为红酵母属 (Rhodotorulasp .)。R1在不同培养基中的耐酸能力基本相同。pH冲击实验显示 ,R1通过泵出H+ 吸收K+ 来维持胞内pH的稳定 ,表明膜H+ _ATPase和K+ 在R1耐酸中发挥作用。R1细胞膜的H+ _ATPase活性与R1生长的pH呈负相关。通过PCR克隆了R1的H+ _ATPase基因 (pma) ,并进行了测序 ,序列比较显示该基因的保守性很高。

A yeast strain R1 was isolated from sludge samples collected from a copper mine. This strain was able to grow under pH value of 1.5～6.0 wtih optimal growth pH being 3.0, which was the typical characters of acidophilies. R1 was preliminary identified as (Rhodotorula sp.). The ability of acid tolerance of R1 in different mediums was almost same. The result of pH shock experiment showed that R1 could maintain a neutral cytoplasmic pH by pumping H^(+ )and absorbing K^(+), which proved the function of H^(+)-ATPase and K^(+) in its acidic tolerance. Its H^(+)-ATPase activity showed a negative correlation with the growth pH of R1.The gene encoding H^(+)-ATPase(pma)was cloned by PCR and sequenced, which had high homology with that of other yeast strain.