陕西浓缩海红果汁中高渗酵母的分离鉴定

Characterization of osmotolerant yeast in malus micromalus makino juice concentrate from shaanxi province

为研究引起海红果浓缩汁污染腐败的高渗酵母,采用YPD高糖培养基对陕西海红果加工厂的海红果浓缩汁中的高渗酵母进行分离纯化,并从耐糖、耐酸及产气性方面对分离菌株的污染能力进行了研究;对分离菌株菌落形态和细胞形态特征进行了描述,并以26SrDNA序列构建系统发育树,确定了分离菌的遗传学位置;进一步研究了分离株在海红果浓缩汁中的生长情况.共获得4株酵母菌,两株为酿酒酵母(Saccharomyces cerevisiae),两株为鲁氏接合酵母(Zygosaccharomyces rouxii);鲁氏接合酵母(Z.rouxii)的耐糖性、耐酸性及产气性强于酿酒酵母(S.cerevisiae),并且鲁氏接合酵母能够在海红果浓缩汁中生长.结果表明:鲁氏接合酵母具有较强的潜在污染能力,会对海红果浓缩汁质量造成威胁,需要加强控制.

In order to identify osmotolerant yeasts which are capable of causing spoilage for malus micromalus makino juice concentrate,the yeasts in malus micromalus makino juice concentrate collected from malus micromalus makino juice processing plants in Shaanxi province were isolated and purified by using YPD media containing high sugar content.The sugar tolerance,acid tolerance,and gas production capability of each yeast isolate were assayed to evaluate the contamination potential.The colony and cell morphology were characterized and the phylogenetic tree based on26S rDNA sequence analysis was constructed to determine the genetic location of isolates.A total of4yeast stains were isolated from concentrated juice,two of which were identified as strain of Saccharomyces cerevisiae,and all the other isolates belonged to Zygosaccharomyces rouxii.All the isolated strains of Z.rouxii displayed better sugar tolerance,acid tolerance,and gas production capability than those isolates of S.cerevisiae,and they were capable of growing in malus micromalus makino juice concentrate.The results suggested that strains of Z.rouxii might pose a threat to the quality of malus micromalus makino juice concentrate,and needed to be controlled in the production line.