| A serious environmental problem caused by the organic solid waste has become an important topic of research. The processing methods of the organic solid wastes are mainly aerobic composting and anaerobic digestion. Aerobic composting is a method which can convert the organic solid wastes into fertilizer that can improve soil nutrient structure without pollution and anaerobic digestion is a conversion of organic solid waste into biogas energy. However, as a traditional treatment, anaerobic digestion has a low yield in the biogas and methane as well. It is necessary to add strains which control the process of anaerobic digestion to get a high concentration of methane gas.On this research, the experimental platform was designed and built and the cattle manure, sugarcane leaf, filters mud of beer factory were used as the materials. By adding urea to get the initial C/N which was value 10.12,15.02, 20.03, and experiments were conducted to study these physicochemical parameters and characteristics of biogas production of the anaerobic digestion process. Through enrichment and screening for many times, and bacteria associated with methane-producing were obtained from the aforementioned mixed materials. Through the morphological, physiological and biochemical identification and amplifying the 16S rDNA sequence of the strain by PCR, cloned and sequenced in NCBI by BLAST, the BLAST result shows that the strain has 99% homology with Lactobacillus, and single factor method was used to investigate the physiological characteristics of this bacterium. Adding this strain to the mixed materials in the early stage to investigate its effect on gas production in the dry anaerobic digestion after conducting a preliminary optimization.Physicochemical parameters were compared during the aerobic composting and anaerobic digestion and the characteristics of gas production and energy resources during the anaerobic digestion with the initial C/N value 15.After anaerobic digestion, the biogas residue was used to aerobic composting, and a series of investigations were carried out during this composting. PCR-DGGE analysis was also used to study bacterial community in these three fermentation processes. Here are the results of the study research.Firstly, the mixture material with initial C/N of 15.02 was the optimal, and the highest cumulative biogas yield was 1748.63mL/kg, the highest methane concentration was 59.26%, the highest daily amount of methane was 13.5835L/kg.Secondly, the strain GXU-LYC02 was able to grow in the temperature which range 15℃ to 45 ℃, and able to grow in the pH which range 3 to 8. Its optimum growth temperature was 30℃, opt～imum pH was 5.5 and optimum concentration of NaCl range 0 mol/L to 01.3mol/L. It can improve the biogas production during the dry anaerobic digestion process after adding the strain to the mixed material.Thirdly, through the study of the bacterial diversity, the bacterial abundance and its community structure were rich and varied in the process of these three fermentation processes, and the bacterial community structure showed relatively great difference between the samples, and the samples had the predominant bacteria in common. Cellulose-degrading strains have become the common advantage of microbial in the samples of aerobic composting and biogas residue in aerobic composting process. In the anaerobic digestion process, Roseburia intestinalis, Fibrobacter succinogenes subsp, Paludibacter propionicigenes, Coriobacterium glomerans, Magnetococcus marinus, Veillonella parvula, Clostridium saccharolyticum, have become the predominant bacteria which were associated with biogas.Fourthly, after the biogas residue by aerobic composting reached maturity, the degradation of organic matter reach 42.13%,however, organic matter does not meet the national department of agriculture standards NY525-2012 (≥45%) requirements. |
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