Dams R I, Paton G I, Killham K
Univali - Universidade do Vale do Itajaí, 5(a) avenida s/n, Bairro dos Municípios, Balneário Camboriú, SC, CEP: 88330-000, Brazil.
Chemosphere. 2007 Jun;68(5):864-70. doi: 10.1016/j.chemosphere.2007.02.014. Epub 2007 Mar 21.
Sphingobium chlorophenolicum is well known as a pentachlorophenol (PCP) degrader. The objective of this study was to evaluate PCP degradation in a loamy sandy soil artificially contaminated with PCP using phytoremediation and bioaugmentation. Measurements of PCP concentrations were carried out using high performance liquid chromatography analyses (HPLC). The toxic effect of PCP on plants was studied through the monitoring of weight plant and root length. The biodegradation of PCP by S. chlorophenolicum in soil was assessed with a bioluminescence assay of Escherichia coli HB101 pUCD607. Bacterial analyses were carried out by plating on Mineral Salt Medium (MSM) for S. chlorophenolicum, MSM for PCP-degrading/tolerant organisms and Trypticase Soy Broth Agar (TSBA) for heterotrophic organisms. The introduction of S. chlorophenolicum into soil with plants showed a faster degradation when compared to the non-inoculated soil. The monitoring of the plant growth showed a protective role of S. chlorophenolicum against the toxicity of PCP. The bioassay confirmed that initial toxicity was lowered while degradation progressed. There was a significant increase of organisms tested in the roots in comparison to those in the soil. This study showed that the presence of S. chlorophenolicum enhanced the PCP degradation in a loamy soil and also it had a protective role to prevent phytotoxic effects of PCP on plant growth. The combined use of bioaugmentation and plants suggests that the rhizosphere of certain plant species may be important for facilitating microbial degradation of pesticides in soil with important implications for using vegetation to stabilize and remediate surface soils.
嗜氯酚鞘氨醇杆菌是一种著名的五氯酚（PCP）降解菌。本研究的目的是评估利用植物修复和生物强化技术对人工受PCP污染的壤质砂土中PCP的降解情况。采用高效液相色谱分析（HPLC）测定PCP浓度。通过监测植物重量和根长来研究PCP对植物的毒性作用。利用大肠杆菌HB101 pUCD607的生物发光测定法评估嗜氯酚鞘氨醇杆菌在土壤中对PCP的生物降解。通过在矿物盐培养基（MSM）上接种培养来分析嗜氯酚鞘氨醇杆菌，在MSM上接种培养来分析PCP降解/耐受菌，在胰蛋白胨大豆肉汤琼脂（TSBA）上接种培养来分析异养菌。与未接种的土壤相比，将嗜氯酚鞘氨醇杆菌引入有植物的土壤中显示出更快的降解速度。对植物生长的监测表明嗜氯酚鞘氨醇杆菌对PCP的毒性具有保护作用。生物测定证实，随着降解过程的进行，初始毒性降低。与土壤中的生物相比，根系中测试的生物数量显著增加。本研究表明，嗜氯酚鞘氨醇杆菌的存在增强了壤质土壤中PCP的降解，并且对防止PCP对植物生长的毒害作用具有保护作用。生物强化和植物的联合使用表明，某些植物物种的根际对于促进土壤中农药的微生物降解可能很重要，这对于利用植被稳定和修复表层土壤具有重要意义。
