Alkali Cellulose Enzyme - Producing Fungus Fg-2 Preliminary Study On Breeding And Characterization

A filamentous fungi FG-2 was screened and isolated from deadwood and alkaline soil. The experiments revealed that the crude cellulase from the strain had good endurance to alkaline, the optimum pH value is about 7.2 at 50°C while having a stable enzyme activity between pH4.4 and pH8.0. This strain was preliminary identified as M.crassa Sh.et Dodge.Fermentation conditions for producing alkaline cellulase by FG-2 were studied. The results showed that, the suitable inoculum age was 4 days, The optimum initial pH value was about 7.0, The optimum culture temperature was about 28°C, The culture period was about 8 days. The maximal alkaline cellulase activity reached 1.20U/mL under the optimal conditions with 2 % bran and 0.5 % (NH4)₂SO₄ as carbon and nitrogen source, respectively.One CMCase (named Q I ) was isolated and purified from the crude cellulase by the use of exclusion chromatography with Bio-Gel P100 and ion-exchange chromatography with DEAE-Sepharose Fast Flow and Q-Sepharose Fast Flow. Q I showed one band on SDS-PAGE with an approximate molecular weight of 60, 000Da. The optimum pH value ofQ I was about 6.8 and the optimum temperature was at 55℃ It also had good alkaline endurance while having a stable enzyme activity between pH4.4 and pH8.0.