Study On The Screening Of Celluloytic Strains And Solid Fermentation Condition

The fifteen Trichoderma fungi,teen penicillium fungi and twenty fifty Chaetomium sp were isolated from soil samples collected from experiment plot in yong shou county. The two mutant strains were obtained from parent strains F2 and A8 though compared with diameters of transparence and cellulase activities. The study on the solid fermentation conditions and properties of mutant strains was carried out. The results showed:The four wild fungi named Trichoderma 10,Trichoderma 11,Penicillium1 and Penicillium 3 were obtained with higher cellulase activities.The transparent diameter statisticsing of mutations from Penicillium 1,Penicillium 3 and F2 though revulsant of ultraviolet radiation and nitrous acid show that the transparent diameter of mutant strains though revulsant of nitrous acid was bigger than those though revulsant of ultraviolet radiation, examined by t-verify, there were the difference between the transparent diameter of mutations though revulsant of nitrous acid and those though revulsant of ultraviolet radiation.Though relativity analysis, related coefficient of the 61 mutations between transparent diameter and two enzyme activities(CMC and FPA) is 0.467﹡﹡ and 0.316﹡(n=61,t0.05＝0.308,t0.01＝0.377) respectively. Therefore transparent diameter could be used as criterion to ridding fungi with high cellulase.The six fungi was induced by ultraviolet radiation and nitrous acid. The mutations H8 and 5x6.9 were illuminated by avicel plate,purification of PDA plate and first,second screening. The cellulase activities of mutations H8 and 5x6.9 were 154.9,14.47 IU/g and 189.1,14.04IU/g respectively.The different composition of medium had some certainly effects on cellulase activities. The highest cellulase activities of mutation H8 was obtained when the ration of rice straw,wheat straw and wheat bran were 6/4 respectively, the highest cellulase activities of mutation 5x6.9 was obtained when the ration of rice straw,wheat bran were 9/1 and 8/2. The cellulase activities of two mutations in rice straw was higher than those in wheat straw. The cellulase activities when inorganic nitrogen was used as nitrogen source were lower than when organic nitrogen used as nitrogen source, the cellulase activities when ammonium nitrate was used as nitrogen source were higher than when ammonium sulfate used as nitrogen source.The experiment of wheat straw's pretreatment showed the cellulase activities were increased when wheat straw soak in urea solution or saturated limewaters. the cellulase activities were increased 300%,91.0% and 630%,1270%. Soaking conditions of urea solution were soaking temperature 10℃,soaking time 24 hours,concentration of urea solution 50g/L. Soaking conditions of saturated limewaters were soaking temperature 10℃ and soaking time 48 hours.The results of twenty-five kinds of Chaetomium sp.'s solid fermentation showed cellulase activities of Chaetomium sp is lower, the average cellulase activities were 15.78 and 0.602IU/g, hence Chaetomium sp did not fit as good fungi to produce cellulase. But some Chaetomium sp grew well , the protein content of Chaetomium sp13.18 can increase 41.0% compared protein content of material. So Chaetomium sp could use as excellent fungi to ferment fodder. The composite leavening,fermentation time and mode had greatly affected on the protein content. With increasing of the composite leavening, the protein content changed curviline, earlier increased later fell. The protein content of cow feed increased by adding carbamide and prolong fermentation time become fungi could grow well. The protein content of mode Ⅱ is higher than that of modeⅠ, for ventilated content added up and fungi grew well. Thereby, the optimum fermentation technologies of cow feed is the composite leavening 10g/kg,adding up carbamide,temperature 30℃,fermentation time 48 hours and water/substrate ratio 2.5:3.