当地下水邂逅DNA:石油类有机污染及其生物降解

When Groundwater Meets DNA:Petroleum Hydrocarbon Stress vs Biodegradation

地下水科学与工程研究发展到今日,已经成为一门涉及多个领域的综合性学科。地下水污染的控制和修复研究更需要跨学科的技术和知识支持,而生物修复作为一种高效低耗修复的技术成为环境领域的研究热点。微生物因其自身特性及其对污染的降解主导特征对确定有机物污染场地的永续修复具有重要意义。简要地综述了地下水有机污染及其原位修复、有机污染物和地下环境微生物的交互作用,进一步聚焦生物降解机制、生物修复和细菌研究。在此基础上以某石油污染场地地下水为例,进行了地下水中分离微生物菌株及其降解特征的实验研究。结果表明:放线菌降解效果最好,细菌和真菌次之;两两组合降解效果好于单菌,表明存在协同作用;不同菌株混合降解率较低,表明具有拮抗作用。通过动力学实验得出对TPH的降解符合一级反应动力学方程及其降解速度和降解半衰期。就微生物对有机组分降解而言,烷烃和总石油烃降解规律相似;难降解组分降解率低,后期因烷烃转化使其浓度升高;苯浓度变化不大。微生物活性实验表明:活菌总数和脱氢酶活性与降解率呈正相关变化。运用生理生化及分子生物学方法鉴定得出了具体的菌种。

Groundwater sciences and engineering developed so far has become a comprehensive discipline involving multiple subjects.Control and remediation of contaminated groundwater need technical and knowledge support from inter-disciplinary effort.Bacterium has been a focus for sustainable remediation of organic contaminated sites.A concise review on groundwater contamination and its remediation,interactions between organic contaminant and microorganisms,bioremediation mechanism,and then bacteria was undertaken.As a case study,a microbial study was carried out at a petroleum contaminated groundwater site to have successfully isolated dominant strains for oil degradation from the oil contaminated groundwater samples.The results showed that the Prokaryotic actinomycetes possessed the best degradation rate,followed by other bacteria and fungi.Pairwise combinations showed obvious better degradation than single bacterium,indicating the presence of synergies.Mixed strains expressed poorer degradation,revealing the antagonistic effect.Dynamics degradation experiment demonstrated TPH degradation follows the 1st order kinetics equation,the degradation rate and half-life of petroleum contamination were obtained.For specific compounds,alkane exhibited the similar degradation to TPH;refractory non-hydrocarbon compounds showed lower degradation rate,it was concentrated later since the transformation of alkanes,little change in benzene.The microbial activity experimental results showed that the biomass and dehydrogenase activity correlated with the biodegradation positively.The specific species of the bacteria were determined by physio-biochemical and molecular biological techniques.