Study On Producing Cellulase From Penicillum By Liquid Fermentation

Cellulase could be used for cellulose hydrolysis.Increasing its activity and lowering its production cost was very important for lignocellulose bioconversion.This paper mainly optimize the fermentation medium and fermentation conditions of the fungi-Penicillium strain JU-A10 provided by State Key Laboratory of Microbial Technology, Shandong University. The main experimental results weresummarized as follows:(1)Mainly studied the influence of seed cultivation time,inoculum,medium volume,temperature,speed and initial pH on cellulase activity, and the result indicated that the optimization fermentation conditoin composed:seed cultivation time 32h, inoculum 10%, medium volume 100ml, temperature 30℃, speed 200r/min and the initial pH5.0. Under these conditions, the filter paper activity and CMC activity increased by 61.57% and 26.68%.(2)Mainly studied the influence of different cellulose materials, such as xylose residue,sorghum bar steam explosion S.F and microcrystalline cellulose on cellulase activity. The results showed that after steam explosion pretreatment of sorghum straw produced higher cellulase activity than no treatment of sorghum straw and to a 3:1 ratio of liquid solution at 0.75% sulfuric acid after 12h immersion, under pressure in 3MP steam explosion 150s is best for cellulase activity.In this condition, the filter paper activity and CMC activity increased by 86.86% and 111.06% compared to without any treatment of sorghum straw, and increased by 13.46% and 22.00% compared to xylose residues as raw materials increased. Microcrystalline cellulose and SF not only as a carbon source,but they have a good induction on the synthesis on cellulase. The effect of microcrystalline cellulose is far better than SF.When adding 1% microcrystalline cellulose, fermentation 96h, the filter paper activity and CMC activity were the highest, and were increased by 45.41% and 41.52% compared to without microcrystalline cellulose. To steam explosion sorghum as raw material rod, the paper also studied the influence of inorganic salts such as magnesium sulfate and calcium carbonate on cellulase activity and the results indicated that the optimal dosage was 0.05% and 0.5%. Filter paper activity were increased by 28.00% and 15.60%, CMC activity were increased by 33.33% and 6.56%.(3)The growing period and cellulase production period of Penicillium JU-A10 are before 36h and after 36h, and the optimal temperature of growth and cellulase production are 32℃and 28℃.By section on temperature control of fermentation process, the filter paper activity and CMC activity increased by 15.1% and 14.42% compared with the 30℃constant temperature fermentation. Initially identified the appropriate pH of the growing period and cellulase production period of Penicillium JU-A10 are both around 5.0. On-line control of pH indicated that when the pH control at 5.0 in whole fermentation process, the filter paper activity and CMC activity increased by 35.01% and 51.21% compared to only adjust the initial pH value and.