Study On Submerged Fermentation Conditions For Cellulase Production From Penicillium Decumbens

Cellulosic materials is the most abundant renewable resources, and the glucose released by hydrolysis of natural cellulosic material, could be used to produce biofuels and other high value-added products, which can effectively alleviate food, and energy crises, environmental pollution and other issues facing the world today.In this paper, with Penicillium decumbens JU-A10, provided by State Key Laboratory of Microbial Technology of Shandong University, the condiotions for celluase production by submerged fermentation were optimized with Arundo donax via steam explosion as substrates.Firstly, the effects of seed culure time, inoculum size, initial pH, temperature, loading capacity, rotation speed of,shaking beds, the concentration of steam explosion Arundo donax and polyurethane on enzyme production were investigated. The optimum conditions for cellulase fermentation were: seed culure time 32h, 10% inoculum, initial pH = 5, temperature 30℃, fermentation media loading 100mL (in 500mL shaking flasks), rotation speed of shaking bed 200 rpm, 1% of the Arundo donax, under which the filter paper activity was 7.43IU/ml, CMC activity was 11.77IU/ml, and the activity values were improved by 1.0 and 1.4 units, respectively, when compared with the results before optimization .Secondly, fed-batch fermentation was investigated. Feeding of wheat bran Arundo donax and microcrystalline cellulose showed to be effective to improve celluase activity. The results showed the best feeding time was 72h, the best supplement feeding amount was 1%wheat bran, Arundo donax, microcrystalline cellulose. Microcrystalline cellulose is more expensive than Arundo donax, and taking into account cost, feeding Arundo donax as the carbon source is more suitable. Filter paper activity is 10.25IU/ml, were improved by 2.0 units, when compared with the results without feeding. After the Microcrystalline cellulose fed, filter paper activity is 7.98IU/ml, were improved by 2.0 units, when compared with the results without feeding.CMC activity were 12.28IU/ml, were improved by 1.8 units. Feeing of 0.2g% ammonium sulfate, sodium nitrate would be also benifical for improving cellulase activity, and filter paper activity were 8.05IU/ml, 8.01IU/ml, respectively, both of which were 0.9 units higher than the control, and CMC activity were 13.93IU/ml, 13.78IU/ml, respectively, which showed little difference when compared with the control.