Isolation And Identification Of The Cellulose Degrading Fungi, And Evaluation Of Their Degrading Abilities

16single colonies of microbes were isolated from23soil samples and3pieces of rotten wood, twohigh-efficiency cellulose-degrading fungi, designated as C006and C008were isolated from the16isolatesby the medium with crystalline cellulose as the only carbon source. The colonial morphology of C006andC008were similar with each other, and they were determined to be Trichoderma spp. by morphologicalresearch, and C006was identified to be Trichoderma atroviride by ITS rDNA molecular identification，andthis is the first report to discover that Trichoderma atroviride has a capacity to degrade crystalline celluloseby biotransfomation. Through the research on their degrading characterastics, transparent degrading-halosappeared on the CM medium of C006and C008, which indicated that both of the isolates had strongcellulose degrading abilities. Cultured in the liquid medium with crystalline cellulose as the only carbonsource, C006and C008could transform the liquid medium into transparent states from turbid states in7days, which indicated that the cellulose in the medium were ultilized evidently. The pH value declinedfrom7.4to2.5in7days when C006was degrading the cellulose, and the stable pH of the medium wasabout3.0finally. This phenomena shows that C006can generate much acid substances when then cellulosewas degrading, and it has a good acid-tolerate ability. This is the first time to discover that crystallinecellulose can be transformed into acid substances. CMCase were detected by DNS method, the resultsshowed that C006and C008had similar enzyme characteristics, the optimal pH for the enzymatic reactionwere both at pH4.0, the activities of the CMCase are very low under the conditions of the pH valves whichwere below3.0and in the basic conditions, which means the cellulase of C006and C008are bothacidophilic. The optimal temperature for the enzymatic reaction were both at55℃; treated with thetemperature of above60℃for half an hour, the remaining cellulase activities were less than40%, whichillustrate the thermostabilities of the cellulase are not remarkable. Metollic ions have strong affects on thecellulase activities, Mn2+and Fe2+could enhance the CMCase activities to about100%; however, Hg+andCu2+could inhibit the relative activities to less than10%. HPLC was used to analyze the acid degradingproducts of C006, malonic acid, actic acid, citric acid, succinic acid, acrulic acid and9mains unknownsubstances were detected. GC-MS was applied for further researching of the acid fermentation broth, andsome complicated secondary metabolites, such as phenols and ketones are detected, but these products were not the key factor for the acid-producing phenomena. Based on the results of gas ghromatogram andthe ethyl esterification of the acid fermentation broth, the acid products generated by the fermentation ofC006are predicted to be some kind of stable and complicated biomacromolecule.