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

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.