Complete mineralization of bisphenol F by a newly isolated Microbacterium sp. F2 eliminates its toxicity to sensitive organisms

Bisphenol F (BPF) is a component of synthetic epoxy resin and polycarbonate plastic. Its residue is frequently detected in water and sediments, posing a threat to aquatic organisms due to the endocrine disrupting effect of BPF. In this study, strain Microbacterium sp. F2, using BPF as the sole carbon source for growth and degrading 98.67 % of 0.10 mM BPF within 24 h, was isolated. Based on the identification of metabolites, strain F2 degraded BPF by the hydroxylation of the bridging carbon atom, and subsequently via oxidation and Baeyer-Villiger reaction to p-hydroxybenzoic acid (PHBA) and 1,4-hydroquinone (HQ), and both of them were further metabolized to provide strain F2 with the carbon source for growth. The half maximal inhibitory concentration (IC50) of BPF, 4,4′-dihydroxybenzophenone (DHBP), 4-hydroxyphenyl 4-hydroxybenzoate (HPHB), HQ and PHBA against Chlorella ellipsoidea at 96 h were 64, 142.5, 205, 325 and 660 μM, respectively. The toxicity of BPF and its metabolites to C. ellipsoidea showed a gradually decreasing trend. The median lethal concentration (LC₅₀) of BPF, DHBP, HPHB, HQ, and PHBA against zebrafish at 96 h were 40.50, 70.31, 71.28, 72.44, and 74.94 μM, respectively. There was no obvious difference in the toxicity of metabolites to zebrafish, but their toxicity was significantly lower than that of BPF. However, the complete mineralization of BPF by strain F2 achieved the detoxification of BPF. This study provides a potential strain for the bioremediation of BPF-polluted environment.