Efficient hexabromocyclododecane-biodegrading microorganisms isolated in Taiwan.

The potential toxicity of hexabromocyclododecane (HBCD), its persistence in the environment, and its high bioaccumulation characteristics pose a need to remediate HBCD in the environment. Bacillus cereus and B. subtilis species complexes we isolated from Taiwan soil are capable of degrading HBCD. B. cereus can degrade HBCD with a half-life only 0.911 days. The highest efficiency of HBCD degradation by B. cereus was achieved at pH 7.0, 35 °C, and 0.10 ppm HBCD. The removal mechanism of HBCD by B. cereus is debromination and its pathway was proposed. The addition of surfactant Tween 60 improved HBCD removal but the addition of CaO, slow-releasing oxygen, did not. These findings can facilitate the bioremediation of HBCD in the environment.