Indigenous microbes from the sediments, whether contaminated with hexachlorobenzene (HCB) or not, could dechlorinate HCB effectively without any acclimation and supplemental nourishment. Temperature seriously affected the HCB-dechlorination: within the measured 15–45 °C span, the optimum range was between 30 and 35 °C. Sulfate-reducing bacteria (SRB), denitrifiers, and acetogens might not be directly involved in the HCB dechlorination. However, the SRB retarded subsequent dechlorination of pentachlorobenzene to tetra- and trichlorobenzenes. Some vancomycin-resistant gram-positive bacteria and methanogens were most likely to be the HCB-dechlorinators. The dechlorination followed the Michaelis–Menten behavior with the k′m and KHCB between 0.45–0.73 mg L−1 day−1 and 3.2–17.2 mg L−1, respectively. These findings suggest a potential HCB treatment and cleanup for wastewater and contaminated site
