Construction And Application Of A High Efficient Complex Microbial System To Degrade Cellulose-Lindane During Composting

A complex microbial (CMS) system capable of degrading cellulose and organochlorine pesticide -lindane with high efficiency was isolated from four samples of different matrial composts in high temperature. It was selected and domesticated through two methods and by combination of different microbial communities. In the paper, the stability of CMS, composition of bacterium, adequate cultivating conditions, and decomposing properties of rice straw were studied in laboratory. The degradation properties of lignin cellulose and lindane by inoculating CMS were studied by simulated and field composting. The result of experiment was just as follows:CMS was composed of seven strains which were able to be cultivated by flat lineation and four were difficult to be cultivated. The proportion of strains was different at various stages during the cultivating process. All these showed that the microbes compose of CMS were various and complex very much. During the first 0³ days, the growth of CMS was showed as form of logarithm. After that it grew slowly, and 5 days later its growth became steadier. The stability and the high efficiency were tested by analyzing pH, degrading capability and single strains constitution in the different cultivation time fermentation liquer.The complex microbial system could decompose filter paper, absorbent cotton, rice straw powder and sawdust effectively, especially had high degrading activity for the materials with higher native cellulose such as filter paper and absorbent cotton. The more cellulose was decomposed, the more lindane was degraded. The optimum concentration of carbon was 0.5% and 1% (w/v). The organic nitrogen source was much better than inorganic nitrogen source on the degrading effect. The optimum concentration of nitrogen was 0.25% and 0.5%, more or less than which the degrading capability would be restrained obviously. The complex microbial system can also keep a higher degrading capability in a wider range of pH, especially under the condition of neutral and hemi-alkaline. Filter paper and lindane can be degraded effectively by the complex microbial system during pH7⁹ which also was the optimum condition of cellulose degrading. The appropriate cultivating way was resting cultivation, the optimum oxygen concentration was 0.07⁰.13mg·L^-1, and the most adaptable temperature was 50℃⁶0℃.With rice straw as the sole carbon source to test the degrading capacity, it showed that the microbial system could degrade dissolved sugar and starch more effiently than cellulose and hemicellulose at the initial stage of fermentation. During the whole period of fermentation, the variation of straw weight and pH of fermenting liquer are identical, and in the initial 5 days the microbial system has higher decomposing activity. By the end of fermentation, the contents of cellulose and hemicellulose reduced 7.39% and 43.76% respectively, while the lignin content had little change.CMS was added to the field and simulated composting to test the possibility of improving the efficiency and eliminating organic pollutant effectively.during the composting. The results indicated that the composite microbial system could improve the degradation of cellulose, hemicellulose and lindane obviously. But the lignin could hardly be degraded, and the composite microbial system had little effect on it. At the same time the composite microbial system could accelerate the decomposing of dissolvedsugar and starch during the initial stage of compost, and prolong the lasting time of high temperature above 60 °C. So it could improve the decomposing of different organic substants and shortening the time of maturity by the tests of different maturity indexes.The thesis was going to improve the degradation efficiency of organic pollutants in composting, decrease the second pollution to environment by reusing of the solid wastes, accelerate the degradation of cellulose substance and shorten the composting time. There were important theory and realism meanings to advance the resource and harmless of organic wastes.