Characterization and Safety Evaluation of Autoclaved Gut Commensal Parabacteroides goldsteinii RV-01

Gut commensals play important roles in maintaining the homeostasis of human health. Previous studies indicated that the abundance of <i>P. goldsteinii</i> in animal hosts was increased by the administration of prebiotics such as polysaccharides purified from iconic oriental medicinal fungi. Subsequently, <i>P. goldsteinii</i> was found to exert beneficial effects on the amelioration of multiple chronic inflammation-associated diseases. Even so, during the process of the development of <i>P. goldsteinii</i> as a next-generation probiotic (NGP), care has to be taken when it is used as a functional food ingredient. In this study, we isolated a novel <i>P. goldsteinii</i> strain, RV-01, from the feces of a healthy adult and carried out comprehensive analyses of its genomic and phenotypic characteristics. Bioinformatic analysis of <i>P. goldsteinii</i> RV-01 revealed the absence of potential virulence genes, as well as the presence of genes and traits potentially beneficial to human health, such as the production of short-chain fatty acids, anti-inflammatory lipopolysaccharides, and zwitterionic capsular polysaccharides, as well as immune regulatory proteins. To circumvent any potential side effects, the <i>P. goldsteinii</i> RV-01 was autoclaved before proceeding to the nonclinical safety assessment. The autoclaved <i>P. goldsteinii</i> RV-01 retained its anti-inflammatory effect in human colon epithelial cells. In addition to the three genotoxicity assays, 28-day subacute and 90-day subchronic animal toxicity studies (the highest dose tested was equivalent to 8.109 × 10¹⁰<i>P. goldsteinii</i> RV-01 cells/kg body weight/day) were also implemented. The results of all studies were negative for toxicity. These results support the conclusion that autoclaved <i>P. goldsteinii</i> RV-01 is safe for use as a food ingredient.