比较基因组学解析谷物醋醋醅中巴氏醋杆菌和欧洲驹形杆菌的功能差异

Comparative genomics reveals the functional differences between Acetobacter pasteurianus and Komagataeibacter europaeus in vinegar pei of Zhenjiang aromatic vinegar

摘要:

【目的】基于比较基因组分析，探究镇江香醋醋醅中不同醋酸菌的功能差异。【方法】利用分离培养技术结合16S rRNA基因全长测序获得不同分类地位的醋酸菌；应用比较基因组学结合发酵性能实现不同醋酸菌生长和代谢的差异比较。【结果】巴氏醋杆菌和欧洲驹形杆菌为镇江香醋醋醅中的主要醋酸菌。其中，欧洲驹形杆菌的GC含量更高、基因组更大。功能注释结果表明巴氏醋杆菌和欧洲驹形杆菌的碳水化合物、氨基酸相关基因数量及种类差异较大，欧洲驹形杆菌的碳水化合物活性酶数量更多。相比巴氏醋杆菌，欧洲驹形杆菌中富集的功能差异基因主要参与磷酸戊糖途径、脂肪酸生物合成、果糖和甘露糖代谢等代谢途径。验证结果表明欧洲驹形杆菌可通过产生更多的乙醇脱氢酶、乙醛脱氢酶和大量的ATP，并改变细胞膜脂肪酸组成来提高乙醇的转化率。【结论】明确了巴氏醋杆菌和欧洲驹形杆菌基因之间的差异。欧洲驹形杆菌通过更多的能量积累、更高的乙醇转化相关酶酶活力和细胞膜脂肪酸组成的改变，来改善胞内微环境以适应高酸环境。本研究得到的结果可加深对不同醋酸菌耐酸机制的理解。

关键词:比较基因组;镇江香醋;醋醅;功能差异

Abstract:

[Objective] To explore the functional differences of different acetic acid bacteria in the vinegar pei of Zhenjiang aromatic vinegar via comparative genomics. [Methods] The taxonomic status of acetic acid bacteria were identified by culture-dependent technology and 16S rRNA gene full-length sequencing. The growth and metabolism of different acetic acid bacteria were compared by comparative genomic analysis combined with fermentation performance tests. [Results] Acetobacter pasteurianus and Komagataeibacter europaeus were the main acetic acid bacteria in the vinegar pei of Zhenjiang aromatic vinegar. K. europaeus had higher GC content and larger genome than A. pasteurianus. Functional annotation showed that the number and types of the genes involved in carbohydrate and amino acid metabolism varied greatly between A. pasteurianus and K. europaeus, and the number of carbohydrate-active enzymes was higer in K. europaeus. The functionally differential genes in K. europaeus compared with A. pasteurianus were mainly involved in the pentose phosphate pathway, fatty acid biosynthesis, and fructose and mannose metabolism. The verification experiment showed that K. europaeus increased the conversion rate of alcohol by producing more alcohol dehydrogenase, acetaldehyde dehydrogenase, and ATP and changing the fatty acid composition of the cell membrane. [Conclusion] This study revealed the genetic differences between A. pasteurianus and K. europaeus in vinegar pei. K. europaeus can improve the intracellular microenvironment to adapt to the high acid environment by massively producing energy and the enzymes involved in ethanol conversion and changing the composition of fatty acids in cell membrane. The results of this study can deepen the understanding of the acid tolerance mechanisms of different acetic acid bacteria.

Key words:comparative genome;Zhenjiang aromatic vinegar;vinegar pei;functional difference