Functional and safety assessment of the postbiotic candidate Haloimpatiens sporogenes FM7315T isolated from Myeolchi-jeot, a traditional Korean fermented anchovy

The functionality and safety of Haloimpatiens sporogenes FM7315 T , an obligate anaerobic bacterium isolated from traditional Korean fermented anchovy, were evaluated to assess its potential as a postbiotic candidate. Genome-based analysis revealed a complete cbi – cob gene cluster for cobalamin biosynthesis, which was supported by the LC-MS/MS detection and ELISA-based quantification of vitamin B 12 in the postbiotic fraction of strain FM7315 T . Genome-level and phenotypic safety assessments revealed no acquired antibiotic resistance genes, mobile genetic elements, virulence factors, hemolytic activity, cytotoxic activity, or production of toxic biogenic amines. Genomic and phenotypic analyses indicated that the observed antibiotic resistance was intrinsic, chromosomal, and non-transferable. Strain FM7315 T exhibited high cell-surface hydrophobicity and antioxidant activity in both cellular and extracellular fractions. Metabolite analyses demonstrated the production of substantial amounts of butyrate and acetate, along with serotonin, 5-hydroxytryptophan, agmatine, putrescine, hippurate, and vitamin B 12 -related metabolites. The lysate of strain FM7315 T significantly enhanced IL-1β, TNF-α, and IL-6 expression without inducing iNOS or COX-2, while upregulating Nrf2 and HO-1, indicating immune activation without excessive inflammatory responses. Collectively, these results demonstrate that H. sporogenes FM7315 T produces multiple bioactive metabolites while maintaining genomic and functional safety, supporting its potential as a postbiotic candidate for gut health modulation and immune support.