高耐性库德里阿兹威氏毕赤酵母的筛选及应用

Screening of a robust high-tolerance Pichia kudriavzevii strain and its application in Baijiu fermentation

白酒发酵过程中功能菌群的耐受性能决定了基酒的产量和品质。为了解决糟醅酸度提高造成的减产降质的实际生产问题,该研究在高温、高酸双胁迫条件下从酱香型白酒酒醅中筛选获得11株具有高耐性的库德里阿兹威氏毕赤酵母(Pichia kudriavzevii),并利用玉米浓醪进行模拟白酒发酵,分析这些菌株的发酵能力和风味物质合成能力。其中,菌株XDNZ_PK05可耐受45℃高温、5 g/L乙酸、70 g/L乳酸和14%(体积分数)乙醇,且具有高产酯低产高级醇的代谢特性,故将其作为强化菌株,应用于酱香型白酒实际生产中。结果显示,强化菌剂的使用可以提高原料利用率20%,提升乙醇产量13%,同时降低正丙醇含量53%,且其他风味物质无显著差异。该研究为传统发酵食品人工可控发酵技术的创制提供了菌种资源和理论支撑。

The tolerance of microbiota in Baijiu fermentation has an important impact on the yield and quality of base Baijiu. To solve the industrial problems of low quality and quantity of base Baijiu due to an exceedingly acid microenvironment caused by the accumulation of the weak organic acid, 11 yeast strains with high tolerance to multiple environmental stresses were screened from the fermented grains of sauce-flavor Baijiu, and identified as Pichia kudriavzevii strains. Furthermore, their capability of production of ethanol and flavor compounds was evaluated by batch fermentation using corn as the carbon source. The results showed that strain XDNZ_PK05 could tolerate 45 ℃, 5 g/L acetic acid, 70 g/L lactic acid and 14% ethanol. It could produce more flavor ester compounds and less higher alcohols. Finally, this strain was applied in the fermentation of sauce-flavor Baijiu. The results showed that the application of XDNZ_PK05 could improve the utility of raw materials by 20%, and increase ethanol production by 13%. Moreover, the n-propanol was decreased by 53%, and there were no significant differences in the amounts of the other flavor compounds. Our study provides strain resources and scientific support for development of controllable fermentation technology of traditional fermented foods.