6:2 fluorotelomer sulfonic acid (6:2 FTSA) is one per- and poly-fluoroalkyl substances commonly detected in the environment. While biotransformation of 6:2 FTSA has been reported, factors affecting desulfonation and defluorination of 6:2 FTSA remain poorly understood. This study elucidated the effects of carbon and sulfur sources on the gene expression of Rhodococcus jostii RHA1 which is responsible for the 6:2 FTSA biotransformation. While alkane monooxygenase and cytochrome P450 were highly expressed in ethanol-, 1-butanol-, and n-octane-grown RHA1 in sulfur-rich medium, these cultures only defluorinated 6:2 fluorotelomer alcohol but not 6:2 FTSA, suggesting that the sulfonate group in 6:2 FTSA hinders enzymatic defluorination. In sulfur-free growth media, alkanesulfonate monooxygenase was linked to desulfonation of 6:2 FTSA; while alkane monooxygenase, haloacid dehalogenase, and cytochrome P450 were linked to defluorination of 6:2 FTSA. The desulfonation and defluorination ability of these enzymes toward 6:2 FTSA were validated through heterologous gene expression and in vitro assays. Four degradation metabolites were confirmed and one was identified as a tentative metabolite. The results provide a new understanding of 6:2 FTSA biotransformation by RHA1. The genes encoding these desulfonating- and defluorinating-enzymes are potential markers to be used to assess 6:2 FTSA biotransformation in the environment.

6:2 氟调聚物磺酸 (6:2 FTSA) 是环境中常见的一种全氟和多氟烷基物质。虽然已经报道了 6:2 FTSA 的生物转化，但影响 6:2 FTSA 脱磺和脱氟的因素仍然知之甚少。本研究阐明了碳源和硫源对红球菌基因表达的影响RHA1 负责 6:2 FTSA 生物转化。虽然烷烃单加氧酶和细胞色素 P450 在富含硫的培养基中的乙醇、1-丁醇和正辛烷生长的 RHA1 中高度表达，但这些培养物仅对 6:2 含氟调聚物醇进行脱氟，但对 6:2 FTSA 没有进行脱氟，这表明6:2 FTSA 中的磺酸盐基团阻碍酶促脱氟。在无硫生长培养基中，烷磺酸单加氧酶与 6:2 FTSA 的脱磺化有关；而烷烃单加氧酶、卤酸脱卤酶和细胞色素 P450 与 6:2 FTSA 的脱氟有关。通过异源基因表达和体外验证了这些酶对 6:2 FTSA 的脱磺和脱氟能力化验。确认了四种降解代谢物，一种被鉴定为暂定代谢物。该结果提供了对 RHA1 进行 6:2 FTSA 生物转化的新认识。编码这些脱磺酶和脱氟酶的基因是用于评估环境中 6:2 FTSA 生物转化的潜在标记。