饲用酵母菌的筛选鉴定及抗逆性分析

Screening, Identification and Stress Resistance of Feed Yeast

为了筛选出可作为微生态制剂及用于发酵饲料的优良菌株,试验以蜂蜜及水果酵素为原料,进行菌株的分离鉴定,并对分离出的酵母菌进行抗逆性研究。结果显示:从蜂蜜中分离出7株菌(A、H、I、J、K、L、M),从苹果酵素中分离出2株菌(DM和DS),从葡萄酵素中分离出2株菌(E1和E3),通过细菌形态学及26S rDNA序列鉴定,确定A是假丝酵母,DM、DS是毕赤酵母,E1是假鲁氏接合酵母,E3是鲁氏接合酵母,H、I、J、K、L和M是酿酒酵母。6株酿酒酵母菌中K的产气能力最强,发酵15 h后产气达到满管,其次是I、J和L;在葡萄糖含量为100~500 g·L^(-1)条件下,6株菌均可以生长,其中J的耐糖性最好;当pH值为1~5时,6株菌均可生长,耐低pH性由高到低为J>L>I>H>M>K;H的高温耐受性最好,I、J和L较好,K和M略差;胆盐浓度为0.03%~0.3%时,I、J和M完全耐受且存活率可达100%。本研究为发酵饲料生产提供具备耐高糖、耐低pH、耐高温、耐胆盐等应用潜力的菌株。

In order to screen superior strains as microecologics, and aimed to use for fermented feed. Natural honey and friut were taken as the materials, isolation and identification were carried on. Meantime, the isolated forage yeasts were carried on the stress resistance. The result showed that seven strains were isolated from natural honey(A, H, I, J, K, L and M), and two strains(DM and DS) were isolated from appleenzyme, two strains(E1 and E3)were isolated from grape enzyme. A was Starmerella sorbosivorans, DM and DS were Pichia deserticola, E1 was Zygosaccharomyces pseudorouxii, E3 was Zygosaccharomyces rouxii, H, I, J, K, L and M were Saccharomyces cerevisiae through the analysis of morphological and 26S rDNA gene sequences identified. Among the six strains of Saccharomyces cerevisiae, K had the strongest gas production and reached full gas production after 15 h of fermentation, followed by I, J and L^(-1) under the condition of glucose content of 100-500 g·L^(-1), all the six strains could grow, among which J had the best sugar tolerance. When the pH value was 1-5, all the six strains could grow,and the high temperature tolerance from high to low, pH was J > L > I > H > M > K;H, I, J and L were better, K and M were slightly worse. When the concentration of bile salt was 0.03%-0.3%, I, J and M were completely tolerated and the survival rate could reach 100%. The study provided potential strains, which had glucose tolerance, level resistance to low pH, thermal stability, and bile tolerance for fermented feed production.