树莓酵素中耐高渗酵母菌的分离鉴定及生长特性研究

从树莓酵素中分离酵母菌,通过形态学特征、生理生化指标及26S r DNA序列分析进行鉴定,并对其生长特性进行研究,以期为植物酵素食品生产提供酵母菌资源。鉴定结果表明:分离出的Y1、Y2、Y3三株菌形态学特征相似,且均可在高糖环境下生长,26S r DNA序列与鲁氏接合酵母的同源相似性均高于99%,确定Y1、Y2、Y3均为鲁氏接合酵母(Zygosaccharomyces rouxii,Z.rouxii);生长特性研究结果表明:当培养基初始葡萄糖含量为300、450、600、750 g/L时,该菌种均可生长,延滞期分别为12、12、36、60 h,葡萄糖初始含量为900 g/L,生长缓慢;当培养基初始pH为1.5和2.0时,菌种的生长受到抑制,当pH为2.5、3.0、3.5时,菌种可以生长,延滞期分别为96、48、48 h。鲁氏接合酵母为树莓酵素中的优势酵母,具有耐高糖、耐低pH等耐高渗特性。 

Screening,identification and properties of osmophilic yeast from raspberry Jiaosu during natural fermentation process

In order to get excellent osmophilic yeast strains for the production of microbial fermentation of plant products, three strains from raspberry Jiaosu were isolated and screened.And the morphological, physio-biochemical characteristics as well as26 S r DNA gene sequence analysis were used to identify the strains.The results showed that the morphological features of Y1, Y2 and Y3 were similar to each other, and they could grow at very high sugar concentrations. The sequences of three isolated osmophilic strains showed a high degree ( > 99%) of homology to those reported in Genbank and they were finally indentificated as Zygosaccharomyces rouxii ( Z.rouxii) . In the study, Z. rouxii could grow at the initial glucose concentration of 300, 450, 600 and 750 g/L and the lag phase were 12, 12, 36 and 60 h, respectively. The strain growed extremely slowly at initial glucose concentration of 900 g/L.When intial p H values were 2.5, 3.0 and 3.5, the adapted strain responded with a lag phase of 96, 48 and 48 h, respectively, and no growth was abserved at intial p H1.5 and 2.0. Z. rouxiiwas the dominant yeasts in raspberry Jiaosu, and it was a sugar-tolerant and low p H tolerated yeast.