Identification of avaC from infant gut microbial isolates that convert 5AVA to 2-piperidone with high efficiency

2-Piperidone has been identified as a biomarker for various human diseases, but its origin in vivo remains poorly understood. Furthermore, 2-piperidone is a crucial industrial raw material, and thus the discovery of novel efficient 2-piperidone synthases may have an important application in its biosynthesis. In this study, we aimed to identify the bacterial source and metabolic mechanism of 2-piperidone from a previously generated infant gut microbial culture collection. We found that 2-piperidone could be produced from 5AVA by four bacterial strains, including Collinsella aerofaciens LFYP39, Collinsella intestinalis LFYP54, Clostridium bolteae LFYP116, and Clostridium hathewayi LFYP18 from 51 bacterial strains. Furthermore, 2-piperidone could be synthesized from proline by cross-feeding between Clostridium difficile LFYP43 and Collinsella intestinalis LFYP54. We employed a gain-of-function library to identify the gene avaC (5-aminovaleric acid cyclase) which can catalyze 5AVA to produce 2-piperidone in C. intestinalis LFYP54. Homologous genes of avaC were also identified and validated in the other three bacterial strains. Gene avaC exhibits a broad distribution in the natural environmental bacteria. Overall, our research identified the gut bacterial strains and the genes that are responsible for the production of 2-piperidone. This study may facilitate the prediction of 2-piperidone-related disease risks through the analysis of gut bacterial community composition, and enhance the efficiency of 2-piperidone in its biosynthesis in industry. ImportanceIn recent decades, it has become a consensus that gut microbiota can affect host health through producing metabolites. However, the complexity of gut flora composition makes finding the sources of the particular metabolite challenging. 2-piperidone is a biomarker for various diseases and a highly valued raw material for nylons. In this study, we identified the gut bacterial strains that can transform 5AVA to 2-piperidone. A novel 2-piperidone synthase gene, avaC, was also identified and characterized. These findings provided new insights into the potential connection between 2-piperidone related diseases and the intestinal flora, as well as a possible novel approach for more efficient biosynthesis of 2-piperidone in industry.