Chen Manjia, Tong Hui, Liu Chengshuai, Chen Dandan, Li Fangbai, Qiao Jiangtao
Guangdong Key Laboratory of Agricultural Environment Pollution Integrated Control, Guangdong Institute of Eco-Environmental and Soil Sciences, Guangzhou 510650, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550009, China.
Chemosphere. 2016 Oct;160:141-8. doi: 10.1016/j.chemosphere.2016.06.061. Epub 2016 Jun 30.
Soil humic substances can be used as redox mediators in accelerating the biotransformation of organic pollutants, and humus-respiring bacteria are widely distributed in soils. However, the impact of humic substances on the soil microbial community during the biotransformation of organic pollutants is expected to be crucial while remains to be unclear. In this study, the biostimulation of indigenous microbial communities and the consequent effects on anaerobic transformation of pentachlorophenol (PCP) by a model humic substance, anthraquinone-2,6-disulfonate (AQDS), were systematically investigated in a paddy soil. The addition of AQDS was observed to increase the production of HCl-extractable Fe(II) and enhance the PCP transformation rates consequently. The pseudo-first-order rate constants of the PCP transformation showed a positive exponential relationship with the AQDS dosage. The terminal restriction fragment length polymorphism (T-RFLP) results indicated the substantial effect of added AQDS on soil microbial community. The enhanced abundance of Geobacter sp. was disclosed to be most critical for accelerated PCP transformation when with AQDS, in which Geobacter sp. functioned for promoting the generation of active Fe(II) and consequently enhancing the PCP transformation rates. The transformation rates of PCP were exponentially correlated with the abundance of Geobacter sp. positively. The findings are expected to improve the understanding of diversity and ubiquity of microorganisms in humic substances-rich soils for accelerating the transformations of soil chlorinated pollutants.
土壤腐殖质可作为氧化还原介质加速有机污染物的生物转化，且腐殖质呼吸细菌在土壤中广泛分布。然而，腐殖质在有机污染物生物转化过程中对土壤微生物群落的影响至关重要，但仍不清楚。本研究在水稻土中系统研究了模型腐殖质蒽醌 - 2,6 - 二磺酸盐（AQDS）对土著微生物群落的生物刺激作用及其对五氯苯酚（PCP）厌氧转化的后续影响。观察到添加AQDS会增加盐酸可提取的Fe(II)的产量，并相应提高PCP的转化速率。PCP转化的准一级速率常数与AQDS剂量呈正指数关系。末端限制性片段长度多态性（T - RFLP）结果表明添加的AQDS对土壤微生物群落有显著影响。研究发现，添加AQDS时，地杆菌属（Geobacter sp.）丰度的增加对加速PCP转化最为关键，其中地杆菌属起到促进活性Fe(II)生成从而提高PCP转化速率的作用。PCP的转化速率与地杆菌属的丰度呈正指数相关。这些发现有望增进对富含腐殖质土壤中微生物多样性和普遍性的理解，以加速土壤中氯代污染物的转化。
