Isolation and Characterization of Two Perfluorobutane Sulfonamide (FBSA)-Degrading Bacterial Strains, Neobacillus sp. LH-1 and Glutamicibacter sp. BO-1, from Estuarine and Marine Sediments

Perfluorobutane sulfonamide (FBSA), an emerging short-chain perfluorooctanesulfonate (PFOS) alternative used in semiconductor manufacturing and fire suppression, has been detected in environmental matrices and poses environmental risks via industrial emissions and product leaching. However, the microbial degradation characteristics of FBSA are still unclear. In this study, two FBSA-transforming bacterial strains (designated LH-1 and BO-1) were isolated from the contaminated sediments of the Liaohe Estuary and the Bohai Sea, northeastern China. Based on 16S rDNA gene sequence analysis, strain LH-1 showed 99.66% sequence similarity with Neobacillus cucumis C7-N-8-8, while strain BO-1 showed 100% similarity with Glutamicibacter nicotianae OTC-16. Genomic analysis identified key degradation-related genes, including oxidoreductases, hydrolases, and genes involved in chloroalkane (LH-1) or fluorobenzoate (BO-1) degradation pathways, providing genetic evidence that supported their FBSA biotransformation potential. After 5 days of incubation with 133.8 nmol/mL FBSA, LH-1 and BO-1 removed 8.78% and 11.37% of FBSA, respectively. Perfluorobutanesulfonic acid (PFBS), perfluorobutanoic acid (PFBA), and perfluoropropionic acid (PFPrA) were detected as biodegradation products, with PFBS and PFPrA as the main products in strains LH-1 and BO-1, respectively. Genome annotation revealed candidate genes associated with deamination, oxidation, desulfonation, decarboxylation, and defluorination, as well as strain-specific enrichment of chloroalkane degradation genes in LH-1 and fluorobenzoate degradation genes in BO-1. Neither strain showed detectable degradation of perfluorooctanoic acid (PFOA) or PFOS, suggesting an apparent preference for the sulfonamide precursor FBSA over terminal perfluoroalkyl acids (PFAAs). This study provides the first genomic and metabolic insights into FBSA biotransformation by coastal sediment bacteria and improves our understanding of the environmental fate of sulfonamide-based PFAS precursors.