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  本文關鍵詞：十氯聯(lián)苯降解菌的分離、降解機理及降解產物的研究　出處：《長安大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 十氯聯(lián)苯 厭氧降解 培養(yǎng)馴化 降解機理

【摘要】：十氯聯(lián)苯是多氯聯(lián)苯中的一種,具有難降解、高毒性、半揮發(fā)、生物蓄積的特性。對于多氯聯(lián)苯的處理技術,國內用的較多且成熟的有高溫焚燒及化學催化。微生物降解方法是近年來研究的熱點。已有研究報道關于好氧降解菌對低氯代多氯聯(lián)苯的降解機理,但低溫、厭氧環(huán)境降解高氯代多氯聯(lián)苯卻少有報道。本實驗以高毒、難降解的十氯聯(lián)苯為研究對象,從渭河陜西中段西安草灘處所取的渭河底泥為微生物的菌源,經過對自然微生物的培養(yǎng)、馴化,分離出能夠以十氯聯(lián)苯為唯一碳源的三株降解菌,分別命名為L1、L2、L3,通過相同條件下不同菌株降解率的比較,得出L1菌株對十氯聯(lián)苯的降解率為76.50%,L2菌株對十氯聯(lián)苯的降解率為64.67%,L3菌株對十氯聯(lián)苯的降解率為53.82%,由此認為L1菌株為優(yōu)勢降解菌,對其革蘭氏染色后顯紫色,微生物為桿狀。通過接觸酶及甲基紅兩種生化鑒定結果可知,L1菌株降解過程中不產生接觸酶,但是有有機酸生成。以培養(yǎng)液pH、十氯聯(lián)苯初始濃度、微生物接種量為影響因素,研究這幾種因素對優(yōu)勢降解菌L1降解效率的影響,得出優(yōu)化的微生物生長條件:pH值為7,十氯聯(lián)苯初始濃度為1.5mg/L,微生物接種量為8m L。通過利用GCMS對十氯聯(lián)苯降解菌的降解產物進行定性分析,推測厭氧條件下微生物先將十氯聯(lián)苯還原為低氯代的多氯聯(lián)苯,相應降解酶的產生使得低氯代的多氯聯(lián)苯化合物中苯環(huán)開環(huán),經過氧化還原、消去等反應進一步分解生成低毒或無毒的有機物。本實驗在接近渭河環(huán)境的條件下馴化、篩選出一種厭氧菌株,且通過實驗確定了其優(yōu)化的降解條件,為生物降解十氯聯(lián)苯提供了有價值的信息;為菌劑的制備以及從污染源頭進行預防治理工程應用的可能性、可行性及運行工況提供了參考。
[Abstract]:Chlordated biphenyls are one of the polychlorinated biphenyls (PCBs), which are difficult to degrade, highly toxic, semi-volatile and bioaccumulative. In recent years, the methods of microbial degradation have been the focus of research. It has been reported on the degradation mechanism of aerobic bacteria to low chlorinated polychlorinated biphenyls (PCBs), but at low temperature. The anaerobic degradation of high chlorinated polychlorinated biphenyls (PCBs) was rarely reported. In this experiment, chlordated biphenyls, which are highly toxic and difficult to degrade, were used as the research object. The sediment of the Weihe River was taken from the Caotan area of Xi'an in the middle section of the Weihe River as the microbial source. Through the cultivation and domestication of natural microorganisms, three strains of biodegradable bacteria with chlordated biphenyls as the sole carbon source were isolated and named L1 / L2 / L3, respectively. The degradation rates of different strains were compared under the same conditions. The results showed that the degradation rate of chlorinated biphenyls of strain L1 was 76.50 and that of strain L2 was 64.67 and that of strain L3 was 53.82%. It is concluded that L1 strain is the dominant biodegradable strain, and its Gram stain shows purple and microorganism is rod-like. The results of contact enzyme and methyl red biochemical identification show that there is no contact enzyme in the degradation process of L _ 1 strain. But there was organic acid formation. With the pH of culture medium, initial concentration of chlordated biphenyls and inoculation amount of microorganism as the influencing factors, the effects of these factors on the degradation efficiency of dominant degrading bacteria L1 were studied. The optimum microorganism growth conditions are as follows: the pH value is 7 and the initial concentration of chlorinated biphenyls is 1.5 mg / L. The microbial inoculation amount was 8 mL. The degradation products of chlorinated biphenyls were qualitatively analyzed by GCMS. It was inferred that under anaerobic condition the chlorinated biphenyls would be reduced to low chlorinated polychlorinated biphenyls (PCBs). The corresponding degradation enzymes make benzene ring open and redox in low chlorinated polychlorinated biphenyls (PCBs). Elimination reaction further decomposed to produce low-toxic or non-toxic organic matter. This experiment was domesticated near the Weihe River environment to screen out an anaerobic strain and determined the optimal degradation conditions through the experiment. Provides valuable information for biodegradation of chlorinated biphenyls; It provides a reference for the preparation of bacteria agent and the possibility, feasibility and operation condition of prevention and treatment engineering from the source of pollution.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X172

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本文編號：1393414