The Study Of Purification And Application Of Cellulases From Trichoderma Reesei

The purification and characterization of cellulase subunits from Trichoderma reesei, the catalytic mechanisms of cellulase subunits to cellulose and the preparation of cellooligosaccharides(COS) from cellulose were investigated. The proliferation of Bifidobacterium used COS as carbon sources and the main catabolites of bifidobacterium to COS were also studied. The main results are as follows:The endoglucanase EGI, EGII and exoglucanase CBHI were purified to homogeneity by ammonium sulfate precipitation, gel filtration Hiprep 26/10 desalting, anion-exchange Source 15Q, cation-exchange Source 15S, gel filtration HiTrep Sephacryl S-200 H R. and gel filtration Superdex 75 PrepGrade. Both endoglucanases and exoglucanase showed apparent homogeneity in SDS-PAGE. The estimated molecular masses of EGI, EGII and CBHI were 56.2, 52.2 and 69.0kDa, respectively.The mechanisms of cellulose degradation by EGI, EGII and CBHI and the preparation of COS from cellulose were investigated. EGI, and CBHI were unsuitable for COS preparation. The optimal conditions of COS preparation from cellulose catalyzed by EGII were 1IU/g cellulose enzyme dosage and for 90 minutes reaction. The ratio of cellobiose, cellotriose and cellotetraose in COS product were 43.8, 34.8 and 7.9%, respectively.In the experiments of invitro fermentation of B. adolescentis used glucose, cellobiose and cellooligosaccharide as carbon sources, the proliferation multiple of B. odolescentis were 5.95,2.14 and 2.84 respectively. Lactic acid was the main metabolite of B. adolescentis used glucose, cellobiose and cellooligosaccharide as carbon sources, then were acetate acid and propionic acid.