东北地区秸秆纤维素降解菌的筛选及高效降解菌系的构建

发布时间：2018-07-07 12:29

本文选题：秸秆 + 纤维素降解菌　；参考：《吉林农业大学》2015年硕士论文

【摘要】：秸秆是农业生产中产生的一种重要的生物质资源,相比煤和石油等矿质资源,是具有可再生性的能源。秸秆资源能否有效利用直接影响到现代农业的可持续发展和环境保护等重大民生问题。当前,大量的秸秆资源被废弃或者焚烧处理,在带来环境问题的同时又导致了资源的白白浪费。通过微生物的作用能够高效的促进秸秆的快速降解,对于加快秸秆还田的推广意义重大,也是目前合理、有效利用秸秆资源行之有效的方法。通过能够高效降解秸秆纤维素类和木质素类物质的微生物的作用,可以有效推动秸秆的快速降解。微生物降解秸秆的产物,可作为土壤腐殖质芳香环形成的重要来源,对于促进土壤腐殖质的形成有积极作用。微生物降解纤维素产生的有机酸,还可作为土壤中固氮菌的碳源,这在一定程度上不仅消除了有机酸对纤维素分解菌代谢的抑制作用,还能够为纤维素降解菌生长发育提供所需的氮源。基于土壤中各微生物种群间形成的这一循环模式,不仅有效解决了秸秆快速腐解的问题,还有利于提高土壤中微生物的活性,对于提高农业生产的效率意义重大。本研究以获得高效纤维素降解菌系,开发出能够用于农业生产的秸秆腐熟剂,为秸秆还田提供技术支持为宗旨,主要开展了高效降解菌株的分离、筛选,高效降解菌系的构建,高效降解菌系培养条件优化,高效降解菌系对玉米秸秆降解的效果等研究。得出了以下主要结论:1.通过在CMC-Na培养基上进行菌株的分离和刚果红染色进行初筛,获得有纤维素降解能力的菌株25株。刚果红染色后能够在有纤维素降解能力的菌株周围产生透明水圈,将透明圈直径与菌落直径的比值和菌株降解纤维素过程CMC和FPA酶活的大小作为复筛的依据,获得了3株纤维素降解能力比较高的菌株:C9、F93和D72,经过初步鉴定菌株C9和F93属于木霉属,菌株D72属于青霉素。2.将筛选过程中获得的3株产纤维素酶活较高的菌株进行组合培养,测定各组合菌系的CMC和FPA酶活,相对单菌株而言,组合菌系的纤维素酶活性大大提高,获得了一组能够高效降解纤维素的菌株组合ZH4,其CMC和FPA酶活分别达到了3.18 U/mL和1.67 U/mL。3.为了能够更好的利用本研究中构建的纤维素高效降解菌系,发挥其高效降解秸秆的作用,本研究对高效降解菌系的培养条件进行了详细的优化研究。通过对培养时间、培养温度、培养基初始pH值和氮源等对菌系产酶活性的影响的研究,确定了高效降解菌系高效产酶的最适宜条件,该菌系ZH4产酶的高峰期是培养第4d,最适宜产酶的培养温度是35℃、最适宜产酶的培养基pH值是6.5、最适宜菌系产酶的培养基氮源为蛋白胨和尿素。4.为了探究实验中所构建的纤维素高效降解菌系在实际生产中的应用效果,本研究对构建的高效纤维素降解菌系对玉米秸秆降解效果进行了研究。将构建的高效纤维素降解菌系在其最适产酶条件下进行玉米秸秆发酵,对菌系降解玉米秸秆前后的失重率进行测定,实验结果显示实验所构建的高效降解菌系对玉米秸秆的降解效果良好,降解秸秆的失重率达到34.52%,与单一菌株降解相比失重率提高了21.3%-59.6%。鉴于该菌系于常温条件下筛选所得,因此对于推广至生产实践有重要的现实意义。
[Abstract]:Straw is an important biomass resource in agricultural production. Compared with coal and oil, it is a renewable energy resource. The effective utilization of straw resources can directly affect the sustainable development of modern agriculture and environmental protection. At present, a large number of straw resources are abandoned or burned. At the same time it brings environmental problems, it leads to the waste of resources. Through the effect of microorganism, it can effectively promote the rapid degradation of straw. It is of great significance to accelerate the promotion of straw returning. It is also an effective method to effectively utilize straw resources at present. By the efficient degradation of straw cellulose and lignin. The effect of microbial biomass can effectively promote the rapid degradation of straw. The product of microbial degradation of straw can be used as an important source of the formation of soil humus aromatic ring, and has a positive effect on the formation of soil humus. Microbial degradation of organic acids from cellulose can also be used as a carbon source of nitrogen fixing bacteria in soil. It can not only eliminate the inhibitory effect of organic acids on the metabolism of cellulose decomposing bacteria, but also provide the necessary nitrogen source for the growth and development of cellulose degrading bacteria. Based on this cycle pattern formed among the microorganisms in the soil, it not only effectively solves the problem of fast decomposition of straw, but also helps to improve the microbial activity in the soil. The purpose of this study is to improve the efficiency of agricultural production. In order to obtain high efficiency cellulose degrading bacteria system, we develop a straw decomposing agent which can be used in agricultural production, and provide technical support for the straw returning to the field. The following main conclusions were obtained as follows: 1. through the isolation of strain and Congo red staining on the CMC-Na medium, 25 strains with cellulose degradation ability were obtained. After Congo red staining, it could produce transparency around the strain with cellulose degradation ability. The water circle, the ratio of the diameter of the transparent circle to the colony diameter and the size of the strain CMC and FPA enzyme in the cellulose degrading process were used as the basis for rescreening. 3 strains with high cellulose degradation ability were obtained: C9, F93 and D72. After preliminary identification, the strain C9 and F93 belonged to Trichoderma, and the strain D72 belonged to 3 strains obtained in the screening process of penicillin.2.. The strains with high cellulase activity were combined and cultured to determine the CMC and FPA enzyme activities of the combined strains. Compared with the single strain, the cellulase activity of the combined strain was greatly improved, and a group of strains capable of efficiently degrading cellulose ZH4 were obtained. The activity of CMC and FPA enzymes reached 3.18 U/mL and 1.67 U/mL.3. to be better. In this study, the effect of high efficiency degradation of cellulose on the efficient degradation of straw was carried out. The culture conditions of high efficiency degradation bacteria were studied in detail in this study. The effect of culture time, culture temperature, initial pH value and nitrogen source on the enzyme activity of the bacteria was studied, and the highly efficient degrading bacteria were determined. The most suitable condition for high yield enzyme production is that the peak period of ZH4 producing enzyme in this strain is 4D, the optimum incubation temperature for producing enzymes is 35, the optimum medium for producing enzymes is 6.5, the best medium suitable for enzyme production is peptone and urea.4. in order to explore the actual production of cellulose degrading bacteria built in the experiment. In this study, the degradation effect of high efficiency cellulose degrading bacteria on corn straw was studied in this study. The high efficiency cellulose degrading bacteria was built under the optimum enzyme production condition to ferment corn straw, and the weight loss rate before and after the degradation of corn straw were measured. The experimental results showed the efficiency of the experiment. The degradation effect of biodegrading bacteria on corn straw was good, the weight loss rate of the degraded straw reached 34.52%. Compared with the single strain degradation, the weight loss rate was increased by 21.3%-59.6%., because the strain was screened under the condition of normal temperature, so it was of great practical significance to popularize to the production practice.
【学位授予单位】：吉林农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S141.4;S182

【参考文献】