| With the growth of world population and improvement of social economic level, there are many problems, such as the energy crisis and environmental pollution and so on, seriously perplexing the whole world. Therefore, it becomes more and more important to develop new energies. Corn straw belongs to crop residues, which has high-enriched cellulose, so people are paying more attention to the hazard-free treatment and reclamation of corn straw. It is more efficient and less contaminative to use the cellulose enzyme produced by the microbe to hydrolyze corn straw. In view of these advantages, we need to select and separate some microorganisms with high production of cellulase and learn their abilities of degrading cellulose. These researches will play a significant role in decreasing the pressure of agricultural waste to environment and the development of cellulose resources.The experimental samples were from the soil sample of Linyang rot, corn straw corruption and the rot in river channel in northeast of China, among which we selected the microbe with the capability of degrading cellulose. After the first round of selection,19 strains were gained which could grow on carboxymethyl cellulose serving as the only carbon source. Through further screening, we acquired 12 strains which produced obvious transparent circle. Finally, the strain, C5, was chosen as the target strain to do further research by contrasting the filter paper enzyme activities and transparent circles among these strains. This strain was identified as Penicillium.sp through the morphological, physiological and biochemical characteristics, which belonged to the family of Moniliaceae, the order of Hyphomycetales, the class of Hyphomycetes, the phylum of Deuteromycotina. Furthermore, we conducted some experiments of 18s rDNA identification by the analyzing methods of molecular biology and analyzed the ITS sequence of C5. And in final, we determined that the strain was Penicillium decumbens.The strain C5 could produce enzyme by fermentation culture in the improved culture medium, Czapek's medium. What's more, this culture went on under the shake cultivation at 28℃and 120 r/min, and then the cellulase activity of this strain was measured. The result showed that the highest activities of filter paper enzyme (Fpase), endoglucanase (EG/Cen), exoglucanase (CBH/Cex) andβ-glucosidase (β-Gase) were 7.085 IU/mL,3.856 IU/mL, 2.681 IU/mL and 1.487 IU/mL, respectively. After determining the enzyme activity, we could get the filtered production to take a picture through Electronic Speculum Scanning, analyze the shape change of samples and determine the abillity of degrading cellulose. The data indicated that the strain C5 had good ability of producing enzyme, complete enzyme system and high degradation efficiency of corn straw cellulose. During the process of producing enzyme by fermentation, we studied the metabolites by the determination of GC-MS technology after fermentation solution was filtered and concentrated. The result indicated that the main metabolites when Penicillium decumbens C5 degraded corn straw cellulose were isobutyl acetate, ethyl benzoate, amyl alcohol, isopropyl acetate and methyl lactate, respectively. In addition, corn straw was used as carbon resource for the growth and metabolism of Penicillium decumbens C5 during the degradation process to produce acids and esters, and there was the transformation relationship between the primary and secondary metabolites.
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