Wang Cuiping, Liu Haibin, Li Jing, Sun Hongwen
MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, People's Republic of China.
Environ Sci Pollut Res Int. 2014 Sep;21(18):10614-25. doi: 10.1007/s11356-014-3050-1. Epub 2014 Jun 1.
Benzo[a]pyrene (BaP), a five-ring polycyclic aromatic hydrocarbon (PAH), which has carcinogenic potency, is highly recalcitrant and resistant to microbial degradation. A novel fungus, Lasiodiplodia theobromae (L. theobromae), which can degrade BaP as a sole carbon source in liquid, was isolated in our laboratory. To prompt the further application of L. theobromae in remediation of sites polluted by BaP and other PAHs, the present study was targeted toward the removal of BaP and PAHs from soil by L. theobromae. The degradation of BaP by L. theobromae was studied using a soil spiked with 50 mg/kg BaP. L. theobromae could remove 32.1 % of the BaP after 35 days of cultivation. Phenanthrene (PHE) inhibited BaP degradation as a competitive substrate. The tested surfactants enhanced BaP degradation in soil by different extents, and a removal rate of 92.1 % was achieved at a Tween-80 (TW-80) concentration of 5 g/kg. It was revealed that TW-80 could not only enhance BaP bioavailability by increasing its aqueous solubility and decreasing the size of its colloid particles but also increase enzyme secretion from L. theobromae and the population of L. theobromae. Moreover, ergosterol content together with the biomass C indicated the increase in L. theobromae biomass during the BaP biodegradation process in soils. Finally, a soil from a historically PAH-contaminated field at Beijing Coking Plant in China was tested to assess the feasibility of applying L. theobromae in the remediation of polluted sites. The total removal rate of PAHs by L. theobromae was 53.3 %, which is 13.1 % higher than that by Phanerochaete chrysosporium (P. chrysosporium), an effective PAH degrader. The addition of TW-80 to the field soil further enhanced PAH degradation to 73.2 %. Hence, L. theobromae is a promising novel strain to be implemented in the remediation of soil polluted by PAHs.
苯并[a]芘（BaP）是一种具有致癌性的五环多环芳烃（PAH），极难降解且对微生物降解具有抗性。本实验室分离出一种新型真菌——可可毛色二孢（L. theobromae），它能够在液体中以BaP作为唯一碳源进行降解。为推动L. theobromae在受BaP和其他PAHs污染场地修复中的进一步应用，本研究旨在利用L. theobromae去除土壤中的BaP和PAHs。使用添加了50 mg/kg BaP的土壤研究了L. theobromae对BaP的降解情况。培养35天后，L. theobromae能够去除32.1%的BaP。菲（PHE）作为竞争性底物抑制了BaP的降解。测试的表面活性剂不同程度地增强了土壤中BaP的降解，在吐温80（TW - 80）浓度为5 g/kg时，去除率达到了92.1%。结果表明，TW - 80不仅通过增加BaP的水溶性和减小其胶体颗粒尺寸来提高BaP的生物可利用性，还能增加L. theobromae的酶分泌和L. theobromae的数量。此外，麦角固醇含量和生物量碳表明在土壤中BaP生物降解过程中L. theobromae生物量增加。最后，对中国北京焦化厂一个历史上受PAHs污染场地的土壤进行了测试，以评估应用L. theobromae修复污染场地的可行性。L. theobromae对PAHs的总去除率为53.3%，比有效的PAH降解菌黄孢原毛平革菌（P. chrysosporium）高13.1%。向田间土壤中添加TW - 80进一步将PAH降解提高到73.2%。因此，L. theobromae是一种有望用于修复受PAHs污染土壤的新型菌株。
