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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/61296


    Title: 以游離及固定化酵素促進氯酚化合物偶合反應之研究;Oxidative coupling of chlorophenol catalyzed by isolated and immobilized enzymes
    Authors: 王俐涵;Wang,Li-han
    Contributors: 環境工程研究所
    Keywords: 酵素固定化;海藻酸鈉;幾丁聚醣;氯酚偶合;immobilized enzyme;sodium alginate;chitosan;chlorophenol coupling
    Date: 2013-07-24
    Issue Date: 2013-08-22 12:17:46 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 氯酚類化合物常見之處理方式有物理、化學、生物等,其中生物處理方法係利用微生物酵素去除氯酚被認為是對環境較為友善。本研究跳脫生物處理必需將污染物予以降解或被吸收移除的傳統思維,主要藉助微生物酵素催化氯酚產生氧化偶合反應以合成巨大、環境穩定且不具生物利用性之聚合物。為克服游離酵素之不穩定性和易受環境條件影響,選取廉價、易獲得之海藻酸鈉及幾丁聚醣製備固定化酵素並探討其活性影響條件及應用於催化氯酚偶合反應。
    研究結果發現海藻酸鈉及幾丁聚醣固定化條件中利用海藻酸鈉濃度2%及氯化鈣濃度為0.1M;戊二醛濃度1%及酵素鍵結時間12小時所固定之酵素有最佳活性。不同pH值及溫度的活性測定,游離及海藻酸鈉固定化酵素之最佳pH值皆為4,幾丁聚醣固定化酵素則以pH3有最高的活性。游離及固定化酵素在20℃~50℃間有最大活性且差異不大,但固定化酵素之熱穩定性及儲存穩定性皆較游離酵素佳。
    氯酚偶合實驗中,酵素添加量越多、反應時間越長、過氧化氫添加量越少,酵素可催化氯酚偶合產生新物質且偶合產物量也越多。固定化酵素能重複催化偶合氯酚,固定載體上之酵素活性顯示海藻酸鈉大於幾丁聚醣,但幾丁聚醣催化偶合效果則較穩定。酵素應用於不同溫度及pH值條件下偶合氯酚,固定化酵素在溫度20℃至60℃催化偶合效果較游離酵素穩定,且較能忍受高pH值的變異。
    In this study, chlorophenol removal by enzyme was carried out. Oxidative coupling of chlorophenol was catalyzed by enzyme to form eco-friendly polymer. The enzyme was immobilized by sodium alginate and chitosan for the convenience of experimental design.
    The optimal activity of the immobilized enzyme was found when the concentrations of the sodium alginate, calcium chloride, and flutaraldehyde were 2%, 0.1 M, and 1%, respectively, with 12 hours of immobilization. The optimal acidity for the mobilized enzyme and the one immobilized by sodium alginate was found at pH 4
    optimal acidity of the enzyme immobilized by chitosan was found at pH 3. Both the mobilized and the immobilized enzymes had the optimal activity between 20 to 50°C. However, the immobilized enzyme possened better thermal stability and life time.
    In the oxidative coupling, there was a positive correlation between the enzyme amount and the yield as well between the reaction time and the yield
    a negative correlation was found between amount of hydrogen peroxide and the yield. Enzyme immobilized by sodium alginate was more active than that of immobilized by chitosan, but the coupling was more stable with the chitosan-immobilized enzyme. Between 20 to 60°C, the coupling of chlorophenol by the immobilized enzyme was more stable than the coupling by the mobilized one. Higher coupling yield was found with lower acidity.
    Appears in Collections:[環境工程研究所 ] 博碩士論文

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