本文選題：纖維素復(fù)合菌群 + 纖維素酶活�。� 參考：《石河子大學(xué)》2015年碩士論文

【摘要】：為了實(shí)現(xiàn)高效降解秸稈的目的,依據(jù)降解秸稈所需酶系的不同進(jìn)行微生物間協(xié)調(diào)組配增加菌種多樣性的理論基礎(chǔ),進(jìn)行了纖維素降解菌的篩選及菌群構(gòu)建,獲得了高效降解纖維素的混合菌群,以期解決秸稈類資源充分利用的問(wèn)題。本試驗(yàn)首先采用剛果紅透明圈的初篩方法,從腐爛棉稈、牛瘤胃液、森林朽木等樣品中初步分離篩選出10株能夠降解纖維素的菌株,并對(duì)降解作用較好的菌株采用3,5-二硝基水楊酸比色定糖法(DNS)進(jìn)行菌株CMC酶活測(cè)定,得到高效降解纖維素的菌株N05、N13及N21,將3株高效菌株進(jìn)行復(fù)合菌群的構(gòu)建;通對(duì)優(yōu)化菌群的培養(yǎng)條件從而使菌群降解能力達(dá)到最大;采用失重法和掃描電鏡觀察研究菌群的降解能力;最后對(duì)N05、N13及N21這3株菌進(jìn)行形態(tài)及分子鑒定。通過(guò)上述試驗(yàn)得到以下結(jié)果:(1)用剛果紅纖維素培養(yǎng)基對(duì)采集的樣品進(jìn)行初篩依據(jù)透明圈直徑/菌落直徑的比值(D/d),得到10株具有較強(qiáng)分解纖維素能力的菌株。然后將這些菌株接種到液體產(chǎn)酶培養(yǎng)基中測(cè)定其CMC酶活性進(jìn)行復(fù)篩,最終篩選出N05、N13、N21 3株高效纖維素降解菌株。將這3株菌株進(jìn)行組合培養(yǎng),通過(guò)對(duì)酶活性的測(cè)定比較,得到一個(gè)效果最好組合SDP(N05+N13+N21)。(2)在液體產(chǎn)酶培養(yǎng)條件下研究溫度、培養(yǎng)時(shí)間、初始pH和氮源對(duì)菌群SDP纖維素酶活性的影響。結(jié)果顯示,菌群降解秸稈發(fā)酵培養(yǎng)條件的優(yōu)化組合為14(A3 B1 C5 D3),即培養(yǎng)溫度為30℃,培養(yǎng)時(shí)間周期為5 d,氮源為NH4NO3,初始pH值為6.0。(3)菌群SDP對(duì)玉米秸稈的降解能力較強(qiáng),在被降解之前含有纖維素36.58%、半纖維素25.60%和木質(zhì)素16.35%。到第8 d培養(yǎng)結(jié)束時(shí)纖維素降低了25.37%,半纖維素降低了27.32%,木質(zhì)素降低了15.29%。通過(guò)對(duì)比玉米秸稈的被微生物降解前后的掃描電鏡圖可知,經(jīng)過(guò)微生物的降解作用,木質(zhì)纖維素的結(jié)構(gòu)遭到破壞,變得松散,結(jié)晶度下降,混合菌群對(duì)玉米秸稈的降解效果要比單一菌株好。(4)對(duì)菌株N05、N13和N21進(jìn)行形態(tài)學(xué)觀察和16S r DNA及18S r DNA基因測(cè)序和序列分析,經(jīng)鑒定N05、N13和N21分別為真菌屬的塔賓曲霉(Aspergillus tubingensis),巨大芽孢桿菌(Bacillus megaterium)和枯草芽孢桿菌(Bacillus sp.LX-102)。在國(guó)內(nèi)外已有的研究報(bào)道中,纖維素降解菌主要集中在纖維單胞菌(Cellu-lomonas)、假單胞菌(Pseudomonas)、梭菌(Clostridium)和芽孢桿菌(Bacillus),而關(guān)于塔賓曲霉降解纖維素的研究,還幾乎未見(jiàn)報(bào)道�；旌暇豪w維素降解效果高于單一菌株,本試驗(yàn)為微生物混合培養(yǎng)降解纖維素提供了理論基礎(chǔ)。
[Abstract]:In order to degrade straw efficiently, the selection and construction of cellulosic degrading bacteria were carried out on the basis of the different enzyme systems needed to increase the diversity of microbial species. In order to solve the problem of making full use of straw resources, a mixture of cellulose-degrading bacteria was obtained. In this experiment, 10 strains which can degrade cellulose were isolated from rotting cotton stalk, bovine rumen fluid and forest wood by the method of Congo red transparent circle. The enzyme activity of CMC was determined by DNS-DNSS, and the strains N05N _ (13) and N _ (21) were obtained, and the three high-efficient strains were used to construct the complex bacterial community of N05N _ (13) and N _ (21). Tongduan optimized the culture conditions of the microflora so as to maximize the biodegradation ability of the microflora; observed the degradation ability of the flora by weightlessness method and scanning electron microscope; finally, carried out morphological and molecular identification of the three strains N05N13 and N21. The results were as follows: (1) according to the ratio of transparent circle diameter to colony diameter (D / d), 10 strains with strong cellulolysis ability were obtained by using Congo red cellulose medium. Then these strains were inoculated into liquid enzyme producing medium to determine their CMC enzyme activity and screened again. Finally, N05N 13 N 21 3 strains of high efficiency cellulose degradation were screened. The three strains were cultured in combination. The best combination, SDP (N05 N13 N21). (2), was obtained by measuring and comparing the enzyme activity, and the temperature and time of culture were studied under the condition of liquid enzyme production, and the results showed that SDP (N05 N13 N21). (2) was the best combination of the three strains. Effects of initial pH and nitrogen sources on cellulase activity of SDP. The results showed that the optimum culture conditions were 14 (A3B1C5D3), that is, the culture temperature was 30 鈩，

本文編號(hào)：2096550