| Cellulose is the most abundant resources and the most widely distributed source of organic material on earth。Due to many factors such as a lack of Technology, cellulose, as valuable resources, not only fails to get fully utilized, a large part of it has been abandoned and becomes one of the environmental pollutants, which causes a waste of resources and brings great damage to the ecological environment。Using straw as raw material for biogas fermentation, not only can reutilize the waste but also solve the problem of insufficient energy in rural areas to some extent。However, the problems in the process of biogas fermentation has been long, such as the slow start of fermentation and the insufficient use of raw materials。The fundamental way to solve the above-mentioned problems is microbial pretreatment of straw, while at the same time, selecting high cellulose degrading strains and constructing composite microbial inoculants suitable for pretreatment stage of the straw biogas fermentation mean great significance。194 cellulose degrading strains were isolated and screened from the straw-cattle manure, pig manure mature composting, mushroom residue, soils and dry branches and fallen leaves, waste mature composting, which consisted of 79 bacteria,53 actinomycetes and 62 fungi.There was no antagonism among fifteen high cellulose degrading strains were selected by Congo red agar and growth speed and experiments of decomposition of filter paper.By the means of orthogonal test with 15 screened strains,5 highly effective combinations were obtained, the carboxyl methyl cellulase(CMCase) activity were combination 16>combination 10combination 13>combination 2>combination 11. Combination 16 was used to study its adaptability to some environmental factors on the liquid medium. It's showed that the appropriate carbon source was sucrose and cellulose powder, the appropriate nitrogen source was bran and (NH4)2SO4,the best content of KH2PO4 was 0.45%,the best content of MgSO4·7H2O was 0.03%, while the optimal medium pH was 6.5 and culture temperature was 40℃,the optimal incubation time was 6 days.The experiments were set up four treatments for aerobic compost pretreatment with crop straw in the laboratory, it includs self-inoculantion of microbial R(treatment one), fast inoculantion of BYM(treatment two), fast inoculantion of straw(treatment three), no-inoculant(CK)。Tracked by reducing sugar production, variation of the carbon and nitrogen content, degradation rate of cellulose, hemicellulose and lignin, the experiment result showed that added inoculant would accelerate the degradation of straw and improve the quality of compost, there was a significant difference between treatment group and CK group of reducing sugar production, variation of the carbon and nitrogen content, degradation rate of cellulose, hemicellulose and lignin。Comparing the effect among treatment one, treatment two and treatment three during the process of pretreatment, it was shown that self-inoculantion of microbial R was better than the others in the degradation of cellulosic materials, there were significant differences among treatment one and treatment two, treatment three。4 materials after different pretreatment were used for anaerobic biogas fermentation, within which gas production, variation of pH, the degradation rate of cellulose, hemicellulose and lignin were tracked。By comparing the effects of anaerobic fermentation of straw among different treatment, it showed that added microbial inoculant to pretreatment would improve the quality of fermentation, there were significant differences between treatment group and CK group in biogas production and the degradation of cellulosic materials, while there were significant differences among treatment one and treatment two, treatment three in gas production, variation of pH, the degradation rate of cellulose, hemicellulose and lignin。So it came to a conlusion that self-inoculantion of microbial R not only could accelerate the degradation of straw and improve the quality of compost during the process of compost pretreatment, but also it would continue to affect the gas production stage, which played an important role in accelerating the fermentation process and improving the utilization of raw materials。Self-inoculantion of microbial R was a kind of efficient microbial inoculant。... |
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