不同土壤/水系統下酵素對PAHs分解作用之影響; Effects of enzyme biodegrade PAHs in different soil-water systems

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Title:	不同土壤/水系統下酵素對PAHs分解作用之影響;Effects of enzyme biodegrade PAHs in different soil-water systems
Authors:	劉庚樺;Keng-Hua Liu
Contributors:	環境工程研究所
Keywords:	界面活性劑;PAHs;酵素;固定化;immobilized;enzyme;PAHs;surfactants
Date:	2003-06-30
Issue Date:	2009-09-21 12:15:20 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	多環芳香烴化合物因在環境中自行分解不易，為提升其去除效率，將界面活性劑淋洗與生物復育同時進行，其會因許多因子影響造成不同之結果。本實驗選用鈣蒙特石，及Triton X-100與Brij 35兩種界面活性劑，利用laccase來分解含不同界面活性劑水/土系統中之naphthalene與phenanthrene，目的在探討多環芳香烴化合物，在不同界面活性劑—水—土壤系統的傳輸行為對生物分解的影響。實驗結果顯示水溶液系統中，laccase在含Triton X-100與Brij 35之溶液中皆會促進PAHs的分解作用，又因微胞比單體為更有效之分佈介質，使得含微胞相時的溶液能促使生物分解速率加快。另外由於Brij 35碳氫鏈較Triton X-100碳氫鏈長許多，形成之微胞結構較大，造成較大的立體結構障礙，故含1.5CMC Triton X-100溶液對PAHs分解率大於Brij 35。土壤/水系統中兩種界面活性劑仍具促進分解作用，且酵素可直接利用溶於水溶性微胞與吸附性微胞之PAHs，使得當平衡溶液為1.5CMC時分解速率大於0.5CMC。分別比較土相與水相之分解情形，因PAHs與酵素在水相之質傳速率大於土相，使得分解行為在水相中較明顯。將酵素固定在鈣蒙特石上，分解在不同界面活性劑溶液的PAHs結果顯示，Triton X-100有促進分解作用，但Brij 35卻有抑制分解之現象，推測原因為固定化後之酵素在Brij 35系統下產生構型改變，故抑制酵素對PAHs之分解。 The hydrophobicity of polycyclic aromatic hydrocarbon compounds (PAHs) results in these compounds being strongly sorbed to soils. The use of surfactants may change the sorption behavior of PAHs in soil environment. Biodegradation is believed an important pathway for removal of PAHs contamination from soil-water systems. The aim of this study was to evaluate the degradation capability of fungal laccase in degrading PAHs including naphthalene and phenanthrene contained in soil-water systems with nonionic surfactants. The nonionic surfactants selected were Triton X-100 and Brij 35. A comparative study was carried out by application of free and immobilized laccases in the soil-water system. In aqueous, addition of Triton X-100 and Brij 35 resulted in enhancement the biodegradation of PAHs. When micelles existed in water systems, PAHs biodegradation was greater than that of below critical micelle concentration (CMC). The same results were also found in soil-water systems. The phenomena can be ascribed to more PAHs partition on into micelles than that of monomers. This situation leading to bioavailable on micellar phase is more effective. To compare the biodegradation rate in difference phase, the results show that in aqueous phase was higher than that of soil phase. On immobilized laccase systems, an inhibition biodegradation in the presence of Brij 35 was observed, and an opposite effect presented in the presence of Triton X-100. Differences phenomenon in bioavailability may correlate with steric hindrance of immobilized laccase and longer polyoxyethylene chain of Brij 35.
Appears in Collections:	[Graduate Institute of Environmental Engineering ] Electronic Thesis & Dissertation

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