Abstract: In this study, the genomic information of three Clostridium kluyveri strains (NBRC 12016, JZZ and DSM 555) were analyzed by comparative genomics with focus on the core enzymes of the hexanoic acid metabolism pathway. It was found that the metabolic pathway of hexanoic acid in NBRC 12016 was not annotated in details and there was mis-annotated information on the core enzyme of the hexanoic acid metabolic pathway in JZZ, acyl coenzyme A dehydrogenase. Bioinformatic analysis was carried out for the key enzyme thiolase (ThlA) of hexanoic acid metabolism in DSM 555. Also, we found that DSM 555 carried three copies of the ThlA gene with sequence polymorphism, which might be related to the substrate specificity of fatty acid chain elongation enzymes. The structural analysis and molecular docking indicated that the catalytic characteristics of ThlA1 contributed to the redox-switch regulatory mechanism. The key catalytic sites and the catalytic process were predicted. The above analysis will be helpful for further improving the hexanoic acid-producing ability of C. kluyveri for application in the brewing of Baijiu.

Key words: Baijiu, Clostridium kluyveri, hexanoic acid, metabolic pathway, thiolase, comparative genomics