Progress in the effects and molecular mechanisms of typical heavy metals on the biotransformation of chlorobenzenes

Abstract:

The co-pollution of heavy metals and organic compounds is one of the major environmental issues today. Understanding the degradation and transformation characteristics of chlorobenzenes (CBs) under the influence of heavy metals is of great significance for remediation of the co-pollution. We summarized the current research status of CB biodegradation, clarified the main functional bacterial genera including Burkholderia, Pseudomonas, Dehalobium, and Dehalococcoides involved in CB degradation, and then outlined the co-pollution status of heavy metals and CBs. The co-pollution of heavy metals and CBs exists in the vast majority of pollution cases. Further, we systematically reviewed the effects of typical heavy metals on the biotransformation and degradation of CBs. Most heavy metal ions exert inhibitory effects on the biotransformation and degradation of CBs under aerobic or anaerobic conditions, and their inhibitory effects are significantly influenced by pH and the species, concentration, and valence state of heavy metals. In addition, the mechanisms of CB transformation and degradation under the influence of heavy metals were analyzed. A molecular mechanism model was constructed with consideration to three influencing mechanisms. Finally, we analyzed the current problems and limitations and prospected the future development direction, aiming to provide support for the remediation of heavy metal-organic co-pollution.