發(fā)布時(shí)間：2018-05-07 07:24

  本文選題：纖維素酶 + 篩選鑒定��； 參考：《沈陽(yáng)農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：纖維素是世界上最豐富的可再生資源,利用微生物生產(chǎn)的纖維素酶將纖維素降解為單糖,再轉(zhuǎn)化為能源、食物和化工原料等。對(duì)人類解決環(huán)境污染和資源短缺等問題具有重大的現(xiàn)實(shí)意義�，F(xiàn)有纖維素酶生產(chǎn)菌存在酶活力低、生產(chǎn)成本高等問題。所以篩選高效降解纖維素的菌株和一些相關(guān)內(nèi)容的研究已成為國(guó)內(nèi)外關(guān)注的熱點(diǎn)。1.本研究從建平縣農(nóng)家柴垛附近7個(gè)采樣點(diǎn)進(jìn)行取樣,通過分離純化得到13株菌株,對(duì)其進(jìn)行綜纖維素、濾紙、微晶纖維素和剛果紅四種篩選培養(yǎng)基初篩,并結(jié)合纖維素酶活力測(cè)定,得到高產(chǎn)纖維素酶的菌株E2.經(jīng)形態(tài)鑒定及系統(tǒng)發(fā)育學(xué)分析,確定該菌株為赭綠青霉(Penicilliumochrochloron)。2.通過試驗(yàn)得到青霉液體發(fā)酵最佳產(chǎn)酶培養(yǎng)條件為:碳源為稻草,碳源濃度為3%,氮源為花生餅粉和KN03,氮源總濃度為0.4%,CaCl2濃度為0.05%;接種量為8%,初始pH為3,發(fā)酵溫度為30℃,培養(yǎng)時(shí)間為144h.在此條件下,最終FPase為28.58U/mL,CMCase 為 54.88U/mL,β-Gase 為 194.16U/mL.3.通過試驗(yàn)得到青霉固體發(fā)酵最佳產(chǎn)酶培養(yǎng)條件為:氮源為花生餅粉,含水量(固體:液體)為1:3,接種量為5%(孢子懸浮液107個(gè)/mL),稻草粒徑為40-60目;初始pH為4,發(fā)酵溫度為30℃,培養(yǎng)時(shí)間為72h.在此條件下,最終FPase為148.29U/g,CMCase 為 256.68U/g,β-Gase 為 230.20U/g。4.將菌株液體發(fā)酵的粗酶液經(jīng)硫酸銨沉淀、SephadexG-75層析得到一組內(nèi)切葡聚糖酶,分子量為29.7kDa.對(duì)內(nèi)切葡聚糖酶的酶學(xué)特性研究表明:酶的最適反應(yīng)溫度為40℃,在40℃時(shí)有良好的熱穩(wěn)定性;最適pH為5.0,在pH為3時(shí)穩(wěn)定;金屬離子K+和Ca2+對(duì)內(nèi)切葡聚糖酶具有促進(jìn)作用,Na+、Mrn2+、ZZn2+、Co2+和Fe2+對(duì)內(nèi)切葡聚糖酶具有不同程度的抑制作用,其中Mn2+、Co2+和Fe2+抑制明顯;對(duì)于內(nèi)切葡聚糖酶的底物專一性,其對(duì)MCC和濾紙有作用,對(duì)水楊素、幾丁質(zhì)和pNPC沒有作用。內(nèi)切葡聚糖酶以羧甲基纖維素鈉為底物的 Km 為 18.45mg/mL,Vmax 為 18.18mg/(mL · min).
[Abstract]:Cellulose is the most abundant renewable resource in the world. Cellulose is degraded into monosaccharide by cellulase produced by microorganisms and then converted into energy, food and chemical raw materials. It is of great practical significance for mankind to solve the problems of environmental pollution and shortage of resources. The existing cellulase producing bacteria have low enzyme activity and high production cost. Therefore, the screening of high efficient cellulose degradation strains and some related research has become a hot spot at home and abroad. 1. In this study, 13 strains were isolated and purified from 7 sampling sites near Nongjia Chaijong, Jianping County, and screened on four screening media: holocellulose, filter paper, microcrystalline cellulose and Congo red. Combined with the activity of cellulase, the high cellulase producing strain E _ 2 was obtained. After morphological identification and phylogenetic analysis, the strain was identified as Penicillium ochrochloron.2. The results showed that the optimum conditions for enzyme production by liquid fermentation of Penicillium were as follows: carbon source was rice straw, carbon source concentration was 3%, nitrogen source was peanut cake powder and KN03, total nitrogen source concentration was 0.410% and CaCl2 concentration was 0.05%, inoculation amount was 8%, initial pH was 3 鈩，

本文編號(hào)：1855956