航天育种研究院微生物团队新成果：诱变育种培育高效耐乙醇功能酵母菌株
内蒙古科学技术研究院航天育种研究院微生物团队联合内蒙古农业大学食品科学与工程学院的研究成果《Factors affecting ethanol tolerance in Kazachstania unispora Mkaz: membrane characteristics and antioxidative stress》发表于国际食品微生物领域权威期刊《Food Microbiology》（中科院一区TOP期刊，影响因子4.6）。团队通过诱变技术成功选育出高乙醇耐受菌株，系统揭示其耐受机制，为食品发酵、生物能源等产业升级提供技术支撑。
单孢哈萨克斯坦酵母（Kazachstania unispora）作为食品级发酵微生物被广泛应用，但在发酵过程中高浓度乙醇抑制其代谢活性的问题长期制约产业效率。团队立足这一痛点，以从内蒙古中西部果园土壤筛选的单孢哈萨克斯坦酵母为研究对象，采用诱变技术定向改良，成功培育出突变菌株Mkaz。该菌株能耐受20 % (vol/vol）的乙醇胁迫，并表现出良好的发酵特性。
通过表型和多组学分析阐明影响其乙醇耐受性的因素：膜特性与抗氧化应激。乙醇胁迫下，Mkaz的总脂肪酸水平显著提升，特别是长链及超长链脂肪酸显著增加，同时海藻糖和麦角固醇的合成提升，改善了膜特性，从而增强乙醇耐受性；腺苷三磷酸酶、超氧化物歧化酶和过氧化氢酶活性的提高通过降低氧化应激促进了乙醇耐受性。基因组和转录组分析揭示了与脂肪酸、海藻糖和麦角固醇生物合成以及氧化应激调节相关的关键突变和差异表达基因。
该研究成果通过功能菌株改造可显著提升发酵效率、降低生产成本，同时其代谢产物能优化发酵食品风味与营养价值，深度契合内蒙古生物发酵产业需求。此研究成果是诱变育种技术与微生物创新的成功融合。下一步，团队将持续深化微生物改良研究，培育更多具备优良特性的功能菌株，为自治区生物发酵产业注入发展动力。
Fig. 1. The relationship between phenotypic characteristics associated with cell membrane and ethanol tolerance in K. unispora Mkaz. (A), grouped column chart of changes in different types of FA between Mkaz and Wkaz. (B), concentric circle diagram reflecting the changes in the percentage of UFA and SFA between Mkaz and Wkaz. (C I), grouped column chart of changes in 37 FA titers between Mkaz and Wkaz. (C II), heatmap of changes in percentage distribution (% of TFA) of 37 FA between Mkaz and Wkaz. (D), grouped column chart of changes in nucleotide concentration with prolonged ethanol stress. (E) and (F), stacked column charts of changes in trehalose and ergosterol content under different ethanol concentrations.
Fig. 2. The relationship between phenotypic characteristics associated with antioxidative stress and ethanol tolerance in K. unispora Mkaz. (A), stacked column chart of changes in plasma membrane ATPase activity under different ethanol concentrations. (B), (C), and (D), grouped column charts of changes in ROS level, SOD activity, and CAT activity under different ethanol concentrations
Fig. 3. Differential expression of genes closely related to ethanol tolerance in Mkaz compared with Wkaz. (A), differential expression of genes associated with cell membrane characteristics. (B) differential expression of genes associated with antioxidative stress.
来源：生物技术研究所
