Study On The Process Of Solid-mixed Fermentation For Cellulase

With the development of the world economy, coal, oil and other fossil fuels become increasingly depleted, energy and environmental problems are world problems. so the governments are very concerned about the new energy sources research. Cellulosic materials is the cheapest and most abundant renewable resources in nature. At present, the utilization of cellulose is still very low, and the technology is not perfect, it caused a lot of wastage of resources, and brought environmental pollution. Cellulase to cellulose down into sugar, this makes it easy to use cellulose. Thus, cellulase activity is a key factor affecting utilization of cellulose, and it restricts the role of cellulose utilization to solve the energy crisis.In this study, we use UV mutagenesis to breeding Trichoderma viride, and investigated the optimum conditions for enzyme production by single-factor experiment and orthogonal test. Then we investigated the optimum conditions for enzyme production by mixed fermentation experiment with Aspergillus niger and Trichoderma viride. Conclusions in the following:(1) This paper introduces the knowledge of cellulase, the cellulase fermentation progress and problems encountered at current.(2) Breeding Trichoderma viride by UV mutagenesis, the enzyme activity of the mutant increased 193%.(3) With the single-factor experiment, we found the greatest impact conditions of the mutant is the amount of ammonium sulfate, the culture time, the culture temperature, and the pH value of the initial medium. (4) With the orthogonal test, we found the optimum conditions for enzyme production of the mutant is that the ratio of wheat bran and straw is 1 to 4, the ratio of dry material with water is 1 to 2, Tuwen20 2%, ammonium sulfate 2%, culture temperature 30℃, culture time 120hours, pH value 4.4。In this conditions FPA activity 12.15 IU/g, C1 activity 16.57 IU/g, Cx activity 18.39 IU/g,β-glucosidase activity 13.81 IU/g.(5) In the mixed fermentation experiment with Aspergillus niger and Trichoderma viride. we found the greatest impact conditions of enzyme activity is the inoculation sequence of strain, the change of culture temperature, the culture time, and and the pH value of the initial medium.(6) With the orthogonal test, we found the optimum conditions for enzyme production of the mixed fermentation is that the ratio of wheat bran and straw is 1 to 4, the ratio of dry material with water is 1 to 2, Tuween20 2%, ammonium sulfate 2%, pH value 5.0, inoculated Trichoderma viride 0.5mL and make fermentation 3 days in the temperature 30℃,then inoculated Aspergillus niger for 2 days in the temperature 25℃. In this this conditions FPA activity 17.45 IU/g, C1 activity 19.35 IU/g, Cx activity 20.56 IU/g,β-glucosidase activity 15.68 IU/g.Compared to the fermentation with Trichoderma viride alone, FPA activity increased 43.62%, C1 activity increased 11.78%, Cx activity increased 11.80%,β-glucosidase activity increased 11.93%.