發(fā)布時間：2018-01-09 18:05

  本文關鍵詞：細菌Comamonas serinivorans C35對木質(zhì)素的降解及其代謝機制初步研究　出處：《江蘇大學》2017年碩士論文　論文類型：學位論文

  更多相關文章： 木質(zhì)素 Comamonas serinivorans C35 過氧化物酶 全基因組測序 降解

【摘要】：木質(zhì)素是自然界中最豐富的可再生芳香族化合物,它的生物合成、分解與自然界中的碳循環(huán)密切相關。木質(zhì)素是由三種基本苯丙烷結(jié)構(gòu)單體(松柏醇、芥子醇和對香豆醇),通過碳碳鍵和碳氧醚鍵等方式連接形成的一種三維網(wǎng)狀無定型酚類聚合物。木質(zhì)素分子量大,結(jié)構(gòu)復雜且不規(guī)則,它作為天然屏障將纖維素和半纖維素緊緊包裹,使得木質(zhì)纖維素難以被水解發(fā)酵,這也是目前生物乙醇生產(chǎn)過程中存在的主要難題。從生物質(zhì)中提取出的纖維素和半纖維素已廣泛應用于乙醇生產(chǎn)、食品和造紙等工業(yè),然而木質(zhì)素作為儲量僅次于纖維素的天然可再生碳源卻仍未被合理利用。目前大多數(shù)的木質(zhì)素殘渣都是隨意堆放或直接燃燒,因此將木質(zhì)素高效降解并實現(xiàn)高值化利用,對開發(fā)以木質(zhì)纖維素為原料的可再生資源具有非常重要的意義。對木質(zhì)素的降解方法已進行了多年的研究,但仍存在諸多問題,如物理法面臨高能耗挑戰(zhàn),化學法會造成二次污染,而生物法雖對環(huán)境友好但效率低。在自然界中真菌是木質(zhì)素生物降解的先鋒者,但由于在基因操縱和蛋白表達等方面存在巨大挑戰(zhàn),目前仍未實現(xiàn)工業(yè)化生成。雖然細菌降解能力弱于真菌,但由于其來源廣泛、生長迅速、易于大規(guī)模應用,近年來在生物質(zhì)利用方面?zhèn)涫苋藗冴P注。因此,篩選能高效降解木質(zhì)素的細菌,研究其木質(zhì)素代謝途徑及機制,將會為木質(zhì)素生物降解實現(xiàn)工業(yè)化生產(chǎn)提供重要的理論基礎。本論文以細菌Comamonas serinivorans C35為研究對象,對其木質(zhì)素降解性能及代謝機制進行了系統(tǒng)研究。主要研究成果如下:(1)菌株Comamonas serinivorans C35能夠在以木質(zhì)素為唯一碳源的培養(yǎng)基上生長,經(jīng)過七天的培養(yǎng),可使堿木質(zhì)素和磨木木質(zhì)素培養(yǎng)基中COD的去除率分別達到44.4%、30.8%,表現(xiàn)出較強的木質(zhì)素降解能力。Comamonas serinivorans C35能使苯胺藍染料褪色,且在粗酶液中檢測到了過氧化物酶和漆酶活性。(2)通過利用傅里葉變換紅外光譜(FTIR)和氣相色譜/質(zhì)譜聯(lián)用(GC-MS)技術(shù)檢測,發(fā)現(xiàn)菌株Comamonas serinivorans C35能夠攻擊堿木質(zhì)素和磨木木質(zhì)素分子結(jié)構(gòu)中的苯環(huán)、側(cè)鏈、醚鍵以及C=O鍵等,使其解聚生成多種單環(huán)芳香族化合物,包括3-甲基苯甲醛、愈創(chuàng)木酚、香草酸、香草醛、丁香酸、丁香醛、對羥基苯甲酸和阿魏酸等。(3)通過全基因組測序和生物信息學分析,發(fā)現(xiàn)菌株Comamonas serinivorans C35的基因組序列中含有編碼木質(zhì)素降解相關酶的基因序列414條,共計15種酶類,包括過氧化物酶、銅氧化酶、漆酶、雙加氧酶和脫羧酶等�；贕C-MS和基因組數(shù)據(jù)分析結(jié)果,發(fā)現(xiàn)菌株Comamonas serinivorans C35存在至少4條木質(zhì)素降解途徑,分別是苯甲酸鹽途徑、苯酚途徑、對羥基苯乙酮途徑和β-酮己二酸途徑,其中對羥基苯乙酮途徑為首次發(fā)現(xiàn)。
[Abstract]:Lignin is one of the most abundant renewable aromatic compounds in nature. Its biosynthesis and decomposition are closely related to the carbon cycle in nature. Lignin is composed of three basic phenylpropane structural monomers (cyperol). A kind of three-dimensional amorphous phenolic polymer formed by carbon-carbon bond and carboxy-ether bond. Lignin has a large molecular weight, complex structure and irregular structure. It acts as a natural barrier to cellulose and hemicellulose tightly wrapped, making lignocellulose difficult to be hydrolyzed fermentation. Cellulose and hemicellulose extracted from biomass have been widely used in ethanol production, food and paper industry. However, lignin as a natural renewable carbon source, second only to cellulose, has not been used properly. At present, most of lignin residues are piled up or burned directly. Therefore, it is very important to degrade lignin efficiently and realize high value utilization, which is very important for the development of renewable resources based on lignocellulose. The degradation methods of lignin have been studied for many years. However, there are still many problems, such as the challenge of high energy consumption in physical method, the secondary pollution caused by chemical method, and the environmental friendly but inefficient biological method. Fungi are pioneers of lignin biodegradation in nature. However, due to the huge challenges in gene manipulation and protein expression, industrialization has not been achieved. Although the ability of bacteria degradation is weaker than fungi, it is easy to be used on a large scale because of its wide source, rapid growth and easy to be used on a large scale. In recent years, people pay more attention to the utilization of biomass. Therefore, screening the bacteria that can efficiently degrade lignin, and study the pathway and mechanism of lignin metabolism. It will provide an important theoretical basis for the realization of industrial production of lignin biodegradation. In this thesis, Comamonas serinivorans C35 is taken as the research object. The degradation performance and metabolic mechanism of lignin were systematically studied. The main results are as follows: 1). Strain Comamonas serinivorans C35 could grow on the medium with lignin as the sole carbon source. After seven days of culture, the removal rate of COD in alkali lignin and lignin grinding medium was 44.4% and 30.8%, respectively. Comamonas serinivorans C35 can make aniline blue dye fade. The activity of peroxidase and laccase was detected in crude enzyme solution by FTIR and GC-MS. It was found that the strain Comamonas serinivorans C35 could attack benzene ring, side chain, ether bond and Cor O bond in alkali-lignin and lignin molecular structure. It depolymerizes to produce a variety of monocyclic aromatic compounds, including 3-methylbenzaldehyde, guaiacol, vanillic acid, vanillin, eugenic acid, eugenaldehyde. P-hydroxybenzoic acid and ferulic acid, etc.) were sequenced and analyzed by bioinformatics. The genomic sequence of the strain Comamonas serinivorans C35 contained 414 genes encoding lignin degradation related enzymes, with a total of 15 enzymes. Including peroxidase, copper oxidase, laccase, dioxygenase and decarboxylase. Based on GC-MS and genomic data analysis results. It was found that there were at least four lignin degradation pathways in strain Comamonas serinivorans C35, namely benzoate pathway and phenol pathway. The p-hydroxyacetophenone pathway and 尾 -ketoadipic acid pathway, of which p-hydroxyacetophenone pathway was first discovered.
【學位授予單位】：江蘇大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：X172;X505

【參考文獻】

相關期刊論文 前10條

1 張曉琰;彭學;政井英司;;木質(zhì)素芳香族化合物降解菌Sphingobium sp. SYK-6的研究進展[J];微生物學報;2014年08期

2 路瑤;魏賢勇;宗志敏;陸永超;趙煒;曹景沛;;木質(zhì)素的結(jié)構(gòu)研究與應用[J];化學進展;2013年05期

3 滕國棟;陳敏亮;;全基因組測序技術(shù)的發(fā)展和應用[J];中國美容醫(yī)學;2013年04期

4 趙燕;薛林貴;李琳;張紅光;;叢毛單胞菌在環(huán)境污染物降解方面的研究進展[J];微生物學通報;2012年10期

5 張馨予;陳芳芳;;氣質(zhì)聯(lián)用技術(shù)的應用[J];現(xiàn)代農(nóng)業(yè)科技;2011年10期

6 潘軍;孫凱佳;賀叢;高騰云;呂超;韓志國;;食用菌在秸稈生物轉(zhuǎn)化飼料中的應用[J];家畜生態(tài)學報;2011年02期

7 李海濤;姚開;何強;賈冬英;;木質(zhì)素的生物降解及其應用[J];皮革科學與工程;2010年06期

8 魏志文;趙士豪;李寶庫;;多菌株發(fā)酵秸稈飼料研究[J];安徽農(nóng)業(yè)科學;2008年32期

9 陳芙蓉;曾光明;郁紅艷;習興梅;;堆肥化中木質(zhì)素的生物降解[J];微生物學雜志;2008年01期

10 池玉杰;伊洪偉;;木材白腐菌分解木質(zhì)素的酶系統(tǒng)-錳過氧化物酶、漆酶和木質(zhì)素過氧化物酶催化分解木質(zhì)素的機制[J];菌物學報;2007年01期

，

本文編號：1402085