Screening Of High Yield Cellulase-Producing Strains And The Study On Its Isolation And Purification

Cellulose is the most abundant organic raw material in the world, and it is the only renewable resource that is available in large quantities. Presently, only a few cellulose are utilized, most of cellulose are wasted and pollute environment. So it has great realistic meaning for human being to solve environment pollution, food shortage and energy crisis that using cellulase produced by microorganism transform cellulose to energy, chemical and food.Cellulase can decompose the natural Cellulose into cellulose molecular china, cellobiose and glucose. At present, the cellulase has applications in abroad field such as food industry, feedstuff, brewage, chemistry industry, weave, curative and entironment protect. It is diversification that the origin of cellulase. It can produced by protozoan, arthropod, mollusk and hexapod. Cellulase also exist in altitude plant. Presently, the origin of microorganism mostly be adopted to produce cellulase.In this research, a strain capable of producing cellulase —Trichoderma viride 13010 was adopted in this research., Trichoderma viride 13010 was mutated by cooperation with complex mutation in the experiment for increasing cellulase production. We got a high enzyme unit strain named Trichoderma viride SP13010. The cellulase was separated and purified from the culture fluid, the strain isolated used as fermentation seed. The purpose of this research is to make the cellulase homogeneous by using the relatively simple purification procedures and achieve high cellulase activity. By means of ammonium sulphate fractional precipitation, Anion-exchange chromatography on DEAE-Sephadex A25, Gel-filtration chromatography on Sephadex G75, the cellulase was separated and purified. The main results were as follows:1. Three mutation agents possessed analogical mortal ratio trend, which positively related to the mutation agent's concentration. The result attested that Ultraviolet radiation (20W, 30cm) irradiated 10min and appended Nitrite-Na (0.3%v/w) then inoculated into flat of Diethylsulfate(0.06mL). The cellulase producing of mutation strain, named Trichoderma viride SP13010 could increase 173.15% after repeated complex mutation. It illuminated that complex mutation could weaken repellence and saturation by single mutation agent.2.The concentration range of the ammonium sulphate fractional precipitation was determined. When the concentration of the ammonium sulphate was 30%, the cellulase activity was very low and the enzyme was mixed with quantities of unwanted proteins. Instead, if the concentration was controlled between 30% to 50%, the product had high activity. Continue to collect the ammonium sulphate precipitation between 50% to 65% and the specific activity was still high. Howerer, if the...