基于fish技术的秸秆干发酵中微生物动动态变化的分析word格式论文.docxVIP

优秀毕业论文 精品参考文献资料 Abstract Anaerobic digestion (AD) had been generally employed to convert waste organic matter to methane and carbon dioxide under anaerobic condition. It is a complicated biochemical process involves variety of microorganism. The community, quantity, growth speed and metabolism activity of the microbes are different during different digestion stages. Interaction of the microbial population and the balance between their metabolism activities directly affects the performance of anaerobic digestion. In this paper, changes of community structure and dynamic variations of the microbes during the dry anaerobic digestion process were studied and the effects of temperature on them were investigated. The study discussed the relationship between microbial community and characteristics of the substrate, in order to optimize the technology of straw biogas dry fermentation. Finally it will provide theory for improving the efficiency of gas production. In order to extract the DNA from the microbes in the substrate of dry anae- robic digestion、physical、chemical、biological and the combination of these me- thods were used to break the cell wall of the microbes. The purity and yield of the DNA extracted by different methods were compared. The results showed that the effect of combination of freezing and thawing processing and enzyme treatment is the best. The purity of DNA (A260/A280) is 1.392±0.027 and its yield is 0.143± 0.016 mg/g, which was significant higher compared with those of the other meth- ods. The purification of crude DNA extracted by bacterial DNA purification kit was increased by 34.6% than adding adsorbent PVP (paraformaldehyde). But the A260/A280 was still below 1.8 that cannot meet the requirement of PCR analysis for microorganism’s quantification. Sample pretreatment method for qualification of the microbes in dry anaero- bic digestion by FISH was optimized. The results showed that using absolute ethanol as cleaning fluid, area and abundance of