Study On The Cellulolytic Characteristics Of A Aerobic Naxibacter Sp.SD-09

Cellulose as the maximum storage capacity of nature’s renewable resource that can bebiodegradated by microorganisms in the soil, its application and transformation for solvingthe world energy crisis is of great significance and potential applications.In this study,aCelluloytic bacterial strain was isolated.the morphology, physiological and biochemical testesand16SrDNA technology of the strain were determined, and the strain was numberedNaxibacter sp.SD-09. In this base, the medium components of the optimal liquid statefermentation, the physiological properties of the crude cellulase and the purification ofcellulase from this strain are studied.The results are illustrated as follows:In this study,Isolation of the CMC-Na strains fromthe maize soil using CMC as the sole carbon source through a transparent ciecle,fourdegradation of CMC-Na ability of the strains.On this basis,analyzed by morphologicalproperties,analysis and phylogenetic analysis of physiological and biochemicalcharacteristics,and preliminary identification of the strain of the strain of the Naxibacteria ofthe genus,named Naxibacter sp.SD-09.In the base of the original fermentation medium, the optimum culture conditions arestudied. The culture conditions include carbon source, nitrogen source, initial pH of medium,inoculation amount and velocity of shaker. The results show that the optimum conditions ofproducing cellulase are as follows: Wheat bran, peptone ratio of2:1, the initial pH is7.5,thebest temperature is30℃, the inoculum size is3mL（The number of spores per ml of mediuminoculated about106）, the shaking speed is120r/min, the solution volume is40mL in the300mL tapered bottle.The highest cellulase activities are obtained by using2%bran as carbonsources and1%peptone as nitrogen source. Under the conditions mentioned above, theactivities of CMCase and Fpase in the cultivation broth after growing120h are58.58×10^-2IUand18.37×10^-2IU respectively.Mn²⁺,Mg²⁺can promote cell producing cellulase, Cu2+, Ag+inhibition of cellulase production strains.The crude cellulase was purified by ammonium sulfate fractionation and freeze-drying.The anlysis shows that the optimum temperature of CMCase activity was30⁶0℃,theoptimum pH of CMCase activity was6.0.The optimum pH of CMCase was4.0. When thetemperature was30℃⁶0℃and the pH was7.0,CMCase and were stabilified.