高耐酸酒酒球菌常压室温等离子体诱变选育及其苹果酸-乳酸发酵研究

Atmospheric and room temperature plasma mutagenesis and malolactic fermentation of highly acid-tolerant Oenococcus oeni

摘要:

【目的】为选育出高度耐酸性酒酒球菌（Oenococcus oeni）突变菌株，研究其胁迫耐受性能及苹果酸-乳酸发酵（malolactic fermentation，MLF）能力。【方法】以酒酒球菌SD-2a为出发菌株，通过常压室温等离子体（atmospheric and room temperature plasma，ARTP）诱变技术，筛选高耐酸性酒酒球菌突变菌株，并探究其乙醇耐受性及在模拟酒和葡萄酒条件下的MLF能力。【结果】经过ARTP诱变处理后，利用pH 3.0的胁迫传代培养和分离纯化等，获得了5株β-葡萄糖苷酶活性较好的耐酸突变菌株，且在高乙醇浓度下表现出了较好的耐乙醇性。其中突变菌株ARTP-2在模拟酒中的β-葡萄糖苷酶活性和l-苹果酸累积降解量最高，且其在葡萄酒中l-苹果酸降解速率快于出发菌株，在第18天完成MLF，发酵后的葡萄酒香气成分的含量显著高于接种SD-2a的酒样。【结论】突变菌株ARTP-2具有良好的胁迫耐受性和MLF能力，对葡萄酒的香气起到积极的作用，为进一步开发优质的MLF商业发酵剂奠定基础。

Abstract:

[Objective] To breed highly acid-tolerant strains of Oenococcus oeni and study their stress tolerance and malolactic fermentation (MLF) performance.[Methods] The mutagenesis of O. oeni SD-2a was carried out with the atmospheric and room temperature plasma (ARTP) method. The ethanol tolerance of the mutants and the MLF performance of the mutants in simulated wine and wine were investigated. [Results] After ARTP mutagenesis, five acid-tolerant mutants with high β-glucosidase activity were isolated by subculture under stress (pH 3.0). The mutants showed strong ethanol tolerance at high ethanol concentrations. Among them, the mutant ARTP-2 had the highest β-glucosidase activity and l-malic acid cumulative degradation in the simulated wine. Moreover, it demonstrated faster l-malic acid degradation rate in wine than O. oeni SD-2a and completed MLF on day 18. The total concentration of aroma components in the wine fermented by ARTP-2 was significantly higher than that by O. oeni SD-2a. [Conclusion] The mutant ARTP-2 had strong stress tolerance and MLF performance and played a positive role in wine aroma. The findings laid a foundation for the further development of high-quality commercial fermenters for MLF.