Co-metabolic degradation of tetrabromobisphenol A by novel strains of Pseudomonas sp. and Streptococcus sp.

Three strains capable of rapidly degrading TBBPA by co-metabolism and utilizing formate as the carbon source, named as J-F-01, J-F-02, and J-F-03, respectively, were isolated from enrichment cultures, which have been treated with 0.5 mg/L TBBPA for 240 d. Based on morphology and 16S rRNA gene sequence analysis, both J-F-01 and J-F-02 were determined to Pseudomonas sp., while J-F-03 was identified as Streptococcus sp. A shorter half-life (6.1 d) of TBBPA was observed in pure culture of J-F-03 when compared with J-F-01 (22.5 d) and J-F-02 (13.6 d). Surprisingly, the degradation of TBBPA was significantly enhanced by the mixed culture of J-F-02 and J-F-03. The optimal degradation conditions for the mixed cultures were determined. Under the optimal conditions, TBBPA (0.5 mg/L) was completely metabolized by the mixed culture within ten days. Moreover, bromide and the metabolisms were detected, and a possible metabolic pathway was deduced from the detection of metabolite production patterns.