接种发酵和自然发酵中酿酒酵母菌株多样性比较

【目的】探究自然发酵和接种发酵两种发酵方式,对霞多丽葡萄发酵中酵母菌种多样性和酿酒酵母菌株遗传多样性的影响。【方法】以霞多丽葡萄为原料,分别进行自然发酵和接种不同酿酒酵母菌株(NXU17-26、UCD522和UCD2610)的发酵,利用26S rDNA D1/D2区序列分析和Interdelta指纹图谱技术分别进行酵母菌的种间及种内水平的区分,通过聚类分析及多样性指数对不同发酵方式下酿酒酵母菌株的多样性进行分析和比较。【结果】自然发酵的发酵曲线较平缓,接种发酵的发酵速度显著快于自然发酵。26S rDNA D1/D2区序列分析将4个发酵中分离到的酵母菌鉴定为6属11种,自然发酵中分离的酵母有5属6种,均为非酿酒酵母(non-Saccharomyces);而接种发酵中的酵母多样性远低于自然发酵,均由酿酒酵母和两种非酿酒酵母组成。Interdelta指纹图谱分析表明,接种UCD2610的发酵中,发酵后UCD2610是优势菌株,其基因型占比为48.78%;接种NXU17-26和UCD522的发酵中,未发现与NXU17-26和UCD522相同的基因型。聚类分析表明,分离自接种UCD522发酵中的酿酒酵母菌株间的遗传差异性较小;而分离自NXU17-26和UCD2610发酵中的酿酒酵母菌株间遗传差异性较大。多样性指数结果表明,接种UCD2610发酵中的优势菌株(UCD2610)在发酵过程中占据更加突出的地位;接种UCD522发酵中分离的酿酒酵母具有更高的多样性,影响其菌株多样性的未知因素较多,且不同基因型酿酒酵母的集中度较高。【结论】发酵方式对霞多丽葡萄发酵中酵母菌种多样性、以及酿酒酵母菌株遗传多样性的影响显著,研究结果对葡萄酒发酵中的微生物控制具有指导意义。

Yeasts diversity of inoculated and spontaneous fermentations

Objective] To explore the effects of spontaneous and inoculated wine fermentations on the yeast diversity and genetic diversity of Saccharomyces cerevisiae. Methods] Spontaneous and inoculated fermentations were conducted with Chardonnay using different S. cerevisiae strains of NXU17-26, UCD522 and UCD2610. We used 26S rDNA D1/D2 sequence analysis and Interdelta fingerprint to distinguish the yeasts at interspecific and intraspecific levels, respectively. The diversity of S. cerevisiae strains was analysed by cluster analysis and diversity index. Results] The fermentation curve of spontaneous fermentation was relatively smooth, and the fermentation speed of inoculated fermentations was significantly faster than spontaneous fermentation. The isolated yeasts were identified as 6 genera and 11 species with 6 species of 5 genera of non-Saccharomyces in spontaneous fermentation. The yeast diversity in inoculated fermentation was far lower than that in spontaneous fermentation, which was composed of Saccharomyces cerevisiae and two non-Saccharomyces. UCD2610 dominated the corresponding fermentation and its genotype accounted for 48.78%; while in the fermentation inoculated with NXU17-26 and UCD522, we didn''t find the same genotype as them. Genetic differences between Saccharomyces cerevisiae strains isolated from UCD522 fermentation were small, while obvious in NXU17-26 and UCD2610 fermentations. Diversity index results showed that UCD2610 showed a more prominent position in the fermentation; Saccharomyces cerevisiae strains isolated in UCD522 fermentation showed a higher diversity, and there were more unknown factors affecting the population diversity and the concentration of different genotypes of Saccharomyces cerevisiae. Conclusion] Fermentation methods have a significant effect on the yeast diversity and the genetic diversity of Saccharomyces cerevisiae strains. This study provides reference for the control of microorganisms during wine fermentation.