Microbial Diversity Analysis In Composting Environment By Metagenomic Method

Rapidly straw composting in factory, which is a very promising industry, is a significant way to transform the source efficiently, that not only can complete large-scale comprehensive utlization of agricultural straw, but also can meet the requirements of peat by intensive agriculture. However, composting is a microbial process which need long time fermentation and fine control. In order to solve these questions, this essay studied the microdiversity during the process of composting fermentation.Straw compost fermentation process is more extensive, and usually with more complex raw material, and more variable fermentation conditions. Repeated experiments told us that when the small niches in the natural environment had similar colonial morphology, they had exactly the same dominant microorganism. Thus, a sampling method based on the morphology of the dominant microbial communities in natural habitats was established. In the composting environment, the nichs with more vigorous hypha were more likely to be with more higher enzyme activity and higher lignolellulose degradation rate, and that’s the site where we got our sample.Both PCR-RFLP and Roche454high-throughput sequencing were used to detect the dominant microorganism in the environment. Two ways gave similar results of the dominant microorganism, but Roche454high-throughput sequencing could privide much more information of the structure of the microbio community and could detect low relative abundance microorganisms.In solid-state fermentation system of corn straw, different layer of the system got very different physicochemical property such as water, oxygen and temperature and so different microorganisms and different lignolellulose degradation rate. There was exactly no degradation in the DO layer; the lignocellulose degradation occurs mainly in the Dl layer, the dominant bacteria and fungi in this layer were Ihermobifida sp.(17%) and Thermomyces sp.(66%) respectively; in the D2layer, there were mainly aerobic facultative anaerobe microorganism; the D3layer had the same condition with silage environment. So turing during the composing process would be inevitable in order to make sure all of the corn straw could be decomposed.Along the entire process of the fermentation of wheat straw, turning made the temperature during the fermentation much lower than that of the corn straw. So p roteobacteria, bacteroidetes, actinobacteria, gemmatimonadetes, firmicutes are main bacteria, and ascomycota is the main fungi. The high temperature of fermentation process could still kill off most of the Pseudoxanthomonas sp.and Flavobacterium sp. which would cause plant disease, to reduce crop disasters.In the composting environment, microbio diversity is really abundant, but there is no doubt that the ones who produce cellulase or hemicellulase have absolute advantage and made the majority of the microbio community. Among them were the thermobifida sp. and theThermomyces sp. In subsequent experiment, we will ues the two kinds of microorganism as inoculum to shorten the fermentation period and increase the fermentation rate to bring more economic benefit.