Villemur R, Déziel E, Benachenhou A, Marcoux J, Gauthier E, Lépine F, Beaudet R, Comeau Y
Centre de Microbiologie et Biotechnologie, INRS-Institut Armand-Frappier, 531 boul. des Prairies, Laval, Québec, Canada.
Biotechnol Prog. 2000 Nov-Dec;16(6):966-72. doi: 10.1021/bp000118j.
High-molecular-weight (HMW) polycyclic aromatic hydrocarbons (PAHs) are pollutants that persist in the environment due to their low solubility in water and their sequestration by soil and sediments. The addition of a water-immiscible, nonbiodegradable, and biocompatible liquid, silicone oil, to a soil slurry was studied to promote the desorption of PAHs from soil and to increase their bioavailability. First, the transfer into silicone oil of phenanthrene, pyrene, chrysene, and benzo[a]pyrene added to a sterilized soil (sandy soil with 0.65% total volatile solids) was measured for 4 days in three two-liquid-phase (TLP) slurry systems each containing 30% (w/v) soil but different volumes of silicone oil (2.5%, 7.5%, and 15% [v/v]). Except for chrysene, a high percentage of these PAHs was transferred from soil to silicone oil in the TLP slurry system containing 15% silicone oil. Rapid PAH transfer occurred during the first 8 h, probably resulting from the extraction of nonsolubilized and of poorly sorbed PAHs. This was followed by a period in which a slower but constant transfer occurred, suggesting extraction of more tightly bound PAHs. Second, a HMW PAH-degrading consortium was enriched in a TLP slurry system with a microbial population isolated from a creosote-contaminated soil. This consortium was then added to three other TLP slurry systems each containing 30% (w/v) sterilized soil that had been artificially contaminated with pyrene, chrysene, and benzo[a]pyrene, but different volumes of silicone oil (10%, 20%, and 30% [v/v]). The resulting TLP slurry bioreactors were much more efficient than the control slurry bioreactor containing the same contaminated soil but no oil phase. In the TLP slurry bioreactor containing 30% silicone oil, the rate of pyrene degradation was 19 mg L(-)(1) day(-)(1) and no pyrene was detected after 4 days. The degradation rates of chrysene and benzo[a]pyrene in the 30% TLP slurry bioreactor were, respectively, 3.5 and 0.94 mg L(-)(1) day(-)(1). Low degradation of pyrene and no significant degradation of chrysene and benzo[a]pyrene occurred in the slurry bioreactor. This is the first report in which a TLP system was combined with a slurry system to improve the biodegradation of PAHs in soil.
高分子量（HMW）多环芳烃（PAHs）是一类污染物，因其在水中溶解度低且会被土壤和沉积物固定，从而在环境中持续存在。研究了向土壤泥浆中添加一种与水不混溶、不可生物降解且具有生物相容性的液体硅油，以促进PAHs从土壤中的解吸并提高其生物可利用性。首先，在三种双液相（TLP）泥浆系统中，测定添加到灭菌土壤（含0.65%总挥发性固体的砂土）中的菲、芘、屈和苯并[a]芘在4天内转移到硅油中的情况，每个系统均含有30%（w/v）土壤，但硅油体积不同（2.5%、7.5%和15% [v/v]）。除屈外，在含15%硅油的TLP泥浆系统中，这些PAHs中有很大比例从土壤转移到了硅油中。PAH的快速转移发生在前8小时，这可能是由于未溶解和吸附较弱的PAHs被萃取所致。随后是一个转移速度较慢但持续的时期，这表明更紧密结合的PAHs被萃取出来。其次，在一个TLP泥浆系统中，利用从杂酚油污染土壤中分离出的微生物群体富集了一个HMW PAH降解菌群。然后将该菌群添加到另外三个TLP泥浆系统中，每个系统均含有30%（w/v）已被芘、屈和苯并[a]芘人工污染的灭菌土壤，但硅油体积不同（10%、20%和30% [v/v]）。所得的TLP泥浆生物反应器比含有相同污染土壤但没有油相的对照泥浆生物反应器效率高得多。在含30%硅油的TLP泥浆生物反应器中，芘的降解速率为19 mg L⁻¹ day⁻¹，4天后未检测到芘。在30%的TLP泥浆生物反应器中，屈和苯并[a]芘的降解速率分别为3.5和0.94 mg L⁻¹ day⁻¹。在泥浆生物反应器中，芘的降解程度较低，屈和苯并[a]芘没有明显降解。这是首次将TLP系统与泥浆系统结合以改善土壤中PAHs生物降解的报告。
