白酒酿造环境中高温菌株的筛选、鉴定及其特性分析

Screening, identification, and characterization of thermophilic strains in the brewing environment of Baijiu

摘要:

【背景】高温菌株在白酒酿造环境中普遍存在，它们是白酒酿造工艺中不可或缺的一类关键微生物菌群。【目的】对白酒酿造环境样品中的高温菌株进行分离、纯化及鉴定，并深入研究它们的生长特性，为其在白酒生产中的应用提供科学依据和理论基础。【方法】对多份酒曲、酒醅和酒糟样品分别进行梯度稀释，然后选取合适稀释梯度样品分别涂布在溶菌肉汤琼脂培养基、酵母浸出粉胨葡萄糖琼脂培养基和马铃薯葡萄糖琼脂培养基上，通过三区划线分离方法进行筛选。【结果】共筛选获得22株高温细菌和18株高温真菌；通过菌落形态观察分析发现有4种细菌和4种真菌菌落形态不同，分别选取这8种微生物进行鉴定，结合形态观察、生理生化特性和分子生物学鉴定为白色链霉菌(Streptomyces albus)、枯草芽孢杆菌(Bacillus subtilis)、解淀粉芽孢杆菌(Bacillus amyloliquefaciens)、鲁戈斯芽孢杆菌(Bacillus rugosus) 4种高温细菌和微小根毛霉(Rhizomucor pusillus)、嗜热棉毛菌(Thermomyces lanuginosus)、坚脆嗜热子囊菌(Thermoascus crustaceus)、樟绒枝霉(Malbranchea cinnamomea) 4种高温真菌，其中鲁戈斯芽孢杆菌和樟绒枝霉在白酒研究中尚无报道；对上述8种不同高温微生物菌种生长温度范围、pH范围和NaCl耐受性等分析发现，不同菌种生物学特性存在差异。【结论】本研究共筛选到4种不同的高温细菌和4种不同的高温真菌，并对其进行鉴定以及生长特性分析，为后续解析这些微生物在白酒酿造中的作用及应用提供了重要保障。

Abstract:

[Background] Thermophilic strains are ubiquitous in the brewing environment of Baijiu and are a microbial group indispensable for the brewing of Baijiu. [Objective] To isolate and identify thermophilic strains in the samples collected from the brewing environment of Baijiu and characterize the growth of the strains, thereby laying a theoretical foundation for the application of the strains in the production of Baijiu. [Methods] Gradient dilution was carried out for the samples of Jiuqu (starter), Jiupei (fermented grains), and Jiuzao (distilled grains), respectively. The samples with suitable dilution factors were then selected and coated on the Luria-Bertani, yeast extract peptone dextrose, and potato dextrose agar media, respectively. The plate streaking method was employed to isolate the strains. [Results] A total of 22 strains of thermophilic bacteria and 18 strains of thermophilic fungi were screened out. Among them, 4 species of bacteria and 4 species of fungi with distinct colony morphology were selected and identified by morphological observation, physiological and biochemical tests, and phylogenetic analysis. The four species of bacteria were identified as Streptomyces albulus, Bacillus subtilis, B. amyloliquefaciens, and B. rugosus, and the four species of fungi were identified as Rhizomucor pusillus, Thermomyces lanuginosus, Thermoascus crustaceus, and Malbranchea cinnamomea. It is worth noting that B. rugosus and M. cinnamomea had not been reported in the research on Baijiu. The eight species showcased differences in the growth temperature range, pH range, and NaCl tolerance. [Conclusion] We screened out, identified, and characterized the growth of four species of thermophilic bacteria and four species of thermophilic fungi, which provided data support for studying the roles and applications of these microorganisms in the brewing of Baijiu.