| Biogas is a kind of clean energy, that was converted by Microorganisms under anaerobic conditions,which translate organic in crops or livestock feces into methane gas.There were large amounts of organic material contented in Crop straw, the dry fermentation technology used in straw can not only reduce the burning caused of pollution, but also can be used as the solid organic for matter available, It can not only reduce the solid waste incineration or discarded brought in environmental pollution, but also can solve the energy crisis. The rate of fermentation and methane gas production rate was be limited,beacause of cellulose material in straw was differenty to used by Microorganisms, So pretreatment was be used before fermentation in order to promote the hydrolysis process. pretreatment by compound bacteria can improve cellulase system,and promote the hydrolysis.We use straw in Gongzhuling rural as raw material, through a straw cellulose as sole carbon source in the culture medium,get a group of Cellulase Producing Compound bacteria in stalks.In test of enzyme production capacity,this Compound bacteria have high cellulose capacity,and Stable in18generations. The enzymatic hydrolysis of cellulose by this compound bacteria1092U/g of dry encymic,and can product enzyme during pH6and7.we use the solid state fermentation medium to study the enzyme production of the compound bacteria,and get the best fermentation conditions was:the most suitable nitrogen source is inoculum amount of0.5%, incubation temperature of30℃, initial pH6.5, reaction time60h.In small laboratory simulation experiments, by orthogonal test to optimize the best pretreatment conditions for initial pH6.5.0.2%of the amount of bacterium inoculation, temperature35℃, processing time of72h, orthogonal experiments measured the gas productionfor0.8m3, the pretreatment strain inoculum size, processing time and temperature are the main influence factor.The composite bacteria and acclimated activated sludge to expand the production of biogas in the laboratory designed by anaerobic fermentation tank, carbon-nitrogen ratio, inoculum size, temperature, pH, time of inoculation, organic load, and finally take the temperature organic loading rate, inoculum and inoculation time influencing factors for the orthogonal experiment, the orthogonal test, and concluded that the effect diagram:the temperature changes in the fermentation process of gas production was rising with the increase of temperature of the the trends in temperature of40℃, gas production; Similarly, inoculation of straw dry fermentation gas production is also gradually increased with increasing temperature; inoculum and the processing time exceeds a certain range will become downward trend. Therefore, the temperature is40℃, the organic loading rate of45g/L,35%inoculum, inoculation time, gas production after48h reached169.5L. Through the use of PBA medium, LB medium and Congo red to identify the medium of the composite flora species composition and the relationship between a preliminary study, five bacteria isolated from the compound bacteria, indicating that the compound bacteriaat least five kinds of cultured strains, including2,3,4strain has a cellulase produced by bacteria synergy between the2nd and the4th, they are there is competition between the bacteria on the3rd.The stability of the compound bacteria has also been discussed through the solid-state culture.20generations of continuous culture, the complex strains of species composition and activity of cellulase can remain stable; In addition, the composite flora of bacteria in the environment has a certain ability to resist. |
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