Cellulase Produced By Fungal Screening And Induction Of The Cellulase And Physicochemical Properties

This article elaborately studied the induction mechanism of different carbon sources to cellulase synthesis of Trichoderma sp. ASS.3711 and Aspergillus sp. B-6, evaluated the cellulase-producing property of B-6 isolated from rubbish compost by contrast to AS3.3711 offered by CCCCM, and studied comparatively the physico-chemical properties of CMCase come from AS3.371 land B-6.As far as the ability of cellulose-decomposing of B-6 was concerned,the results of liquid and solid fermentation were compared with AS3.3711 by measuring the enzyme activitives of exocellulase, edocellulase and total cellulase, and the ability of filter-decomposing was also compared between the two strains. The CMCase ability of B-6 reached 39.2U 15.7U in solid and liquid fermentation respectively, at the same time, FAP(total cellulase)activity reached 4.2U and 3.7U respectively. It was found that B-6 isolated by the method of distinct zone of clearing in Cellulose-Congo red agar medium combined with measuring the enzyme activity of liquid culture filtrates had comparatively higher cellulase activity.By measuring activity of cellulase of strains growing in medium with different carbon sources and of washed mycelium induced by different carbon sources in certain time, it found that the formation of cellulase was regulated by the nature of the carbon source used for B-6 and AS3.3711. Maximal yields of cellulase were obtained on the relatively undegraded cellulose (for example, a -cellulose and Avicel). From the result of electrophoresis, it known that the different components of the enzyme system were expressed cooperatively. In order to study the essence of cellualase induction of different carbon sources, the extracellular, plasm-membrane-bound and intracellular cellulases were made to transform different soluble inducers, and the productions were analyzed by GC chromatogram. The results supported the assumption that cellobiose actedas the direct inducer or the metabolic analogue, B-gentiobiose from cellobiose acted as the true inducer through different metabolism ways in different strains.The crude cellulases from liquid fermentation of B-6 and ASS.3711 were isolated and purified by (NH4)SO4 precipitation, Sephadex G-100 and DEAE-Sepharose CL 6B column chromatography. The CMCase components were purified and some of their physical and chemical properties were studied.