六氯-1,3-丁二烯的微生物降解研究进展

Progress in microbial degradation of hexachlorobutadiene

摘要:

六氯-1,3-丁二烯(hexachlorobutadiene，HCBD)是一种有毒有害的脂肪族氯代烃，曾经作为杀虫剂、除草剂、变压器油和传热流体等化学工业产品的重要成分被广泛应用于生产生活。HCBD因满足《关于持久性有机污染物的斯德哥尔摩公约》中风险筛选标准(如毒性、持久性、远距离环境迁移和生物累积性等)，缔约方于2015年第七次会议中将其增列为持久性有机污染物，2017年又将其列入该公约的附件Ｃ以控制其环境排放量。目前关于HCBD的环境归趋仍是研究热点，但是对于HCBD的微生物降解转化机制尚缺乏深入研究。鉴于此，本文重点回顾并讨论了地下水、底泥等厌氧环境中已报道的HCBD微生物降解转化途径、速率及机制，并从热力学角度阐述HCBD及其降解产物作为电子受体通过还原性脱氯反应被厌氧脱卤微生物代谢转化的可行性。最后，本文根据现有研究结果，提出微生物厌氧降解HCBD的研究展望，包括多组学技术解析HCBD降解功能菌群结构和潜在互作机制、HCBD厌氧降解微生物的分离与纯化，以及HCBD厌氧降解菌剂的开发与污染场地原位生物修复应用等。

Abstract:

Hexachlorobutadiene (HCBD), which is a toxic and harmful aliphatic chlorinated hydrocarbon, had been widely used as an important ingredient in industrial chemicals (e.g., pesticides, herbicides, transformer oils, heat transfer fluids). In 2015, HCBD was added to the persistent organic pollutants (POPs) list based on the fact that it met the risk screening criteria (e.g., levels of toxicity, persistence, bioaccumulation, potential for long-range environmental transport). In 2017, HCBD was added in Annex C of the Stockholm Convention to reduce its unintentional production and emission. Environmental transport and fate of HCBD remain a research focus, and a better understanding of the roles and mechanisms of microorganisms in HCBD degradation and transformation is required. Here, we review the microbial biodegradation pathways, rates, and mechanisms of HCBD biotransformation in anoxic environments (e.g., groundwater, sediments). The feasibility of anaerobic biotransformation of HCBD and its degradation products as electron acceptors by calculating the thermodynamic parameters are demonstrated. Finally, future research on the HCBD microbial degradation is discussed, including the use of multi-omics techniques to unravel microbial community structure and their syntrophic mechanisms; isolation of anaerobic microorganisms capable of HCBD reductive dechlorination; development of highly efficient degradation cultures that can be applied for in-situ bioremediation of HCBD contaminated sites.