Screening Of The Combination Of Cellalolytic Bacteria And Made The Strow-decompsoing Of Stalk

Straw is an important renewable biomass resources in agricultural.However,a large amount of straw resources are unused,abandoned or burned,which caused waste of resources and serious environmental pollution.China is a large agricultural country and the output of straw resource is 600-800 million tons per year.If straw were used efficiently It,which can not only allevlate the energy crisis but also reduce environmental problems.Screening the straw-degrading bacteria strains from rotting straw and soil,was studied,by using optimization of fermentation conditions,enzyme activity and screening of composite microbial system and so on to explores how to use efficiently.The main result as the following:1.Through using strained medium,CMC-Na medium and Congo red staining and32 strains from soil sample,24 strains with hydrolyzed circle diameter and colony diameter ratio HC?2.1 were screened.By measuring the CMC-Na and FPA enzyme activities of 24 strains,12 strains with higher cellulase activity were rescreened.Among them,the CMC enzyme activity of MX1,MX4 and other strains was 0.934U·m L-1 or higher,and the FPA activity was ? 9.86 U·m L-1 or higer.2.According to the determination and analysis of ITS,the 12 strains include 2 strains of Fusarium,2 strains of Penicillium,1 strain of Metarhizium,1 strain of Talaromyces purpureogenus and 6 strains of Aspergillus.Through analyzing the multilocus including SSU,ITS and TUB,MX5 strain was initially identified as Talaromyces purpureogenus,DR9 was Aspergillus proliferans,DR12 was Aspergillus niger,and TR31 was Aspergillus brasiliensis.3.To explore the cellulase activity of MX5,DR9,DR12 and TR31,we used liquid fermentation and solid fermentation that determined CMC-Na activity,FPA activity Endoglucanase activity and ?-gllucosidase activity.The results showed that,the CMC enzyme activity induced by DR12 could reach 21.18U·m L-1;the FPA activity was 19.54 U·m L-1;and exonuclease activity was 20.03U·m L-1 in the liquid fermentation process.The ?-glucosidase activity was 26.69 U·m L-1,which was higher than others.Among the enzymes induced by solid fermentation,the enzyme activity of CMC induced by MX5 strain was the highes which was 17.34 U·m L-1,the highest filter paper enzyme was DR12 which was 17.35 U·m L-1,and the highest exonuclease activity was DR12,which was 16.355 U·m L-1.The highest ?-glucosidase was the TR31 strain and the,enzyme activity of the strain was 24.96 U·m L-1.4.Through screeneding the carbon source,nitrogen source,temperature,humidity,initial p H,inoculum,etc,nutritional conditions and fermentation conditions of the strain DR12,the results showed that the optimum carbon source was millet straw,the optimum nitrogen source is ammonium phosphate.the opitmum fermentation condition were temperature 25? and initial p H7,humidity40%,and inoculation was 1.5 m L/20 g.5.The DR12 single-bacteria decomposing agent and the compound microbial decomposing agent containing three strains of MX5,DR9 and TR31 were prepared by screening and optimization of adjuvant.The results showed that the effective viable cell count of the prepared microbial agent was 7.5×108 ?·g-1 the cellulase activity was 63.39 U·g-1,the water content was 27.26%,and the p H was 6.4.The effective viable cell count of the ternary mixed bacteria was 4×108 ?·g-1,the cellulase activity was 75.36 U·g-1,the water content was 27.67%,and the p H was 6.24.The effective viable cell count of the quaternary mixed bacteria was 1.2×109 ?·g-1,the cellulase activity was 72.46 U·g-1,the water content was 22.01%,and the p H was 6.4,which are meet the requirements of national industry standards.