Screening And Identification Of Cellulase-Producing Strain Of Fusarium Oxysporum, Optimization Of Fermentation Conditions For Producing Cellulase

This research was designed to study cellulase production of 121 strains of Fusarium Oxysporum Schl. based on morphological characters which was stored by our aboratory.Through primary screening and secondary screening, Five strains with higher cellulase were screened out. The ITS rDNA sequence of the five strains were identified, the characterization of fermentation broth of the best strain was determined and Fermentation Conditions for Producing cellulase was optimized.20 strains were screened out by measuring the hydrolysis cercle. After cellulase activity determination of fermentation broth,5 high cellulase activity strains were screened from primary screening strains, one of which named H57-1has the highest cellulase activity of 16.41U/mL.The ITS rDNA sequence of 5strains was determined.The result were analysed by BALST software in Genbank.5 strains were all identified as Fusarium Oxysporum Schl.The characteristics of its crude enzyme were analyzed. The most suitable reactive pH of the CMCase was 5.3,and the most suitable reactive temperature is 62℃.Its PH stability and temperature stability is considerable well. Its adaptability in alkali circumstance as fungus is just required by fungus cellulase and germ cellulase, for fungus cellulase always fear alkali circumstance and germ cellulase activity is always low.The fermentation Conditions of strain H57-1 for Producing cellulase were optimized. The optimal medium contain 48.0g/L bran,14.0g/L peptone,3.9g/L ammonium chloride,2.0g/L sodium dihydrogen phosphate,2.0g/L NaCl and its initial pH is 7.0. The strain was cultured at the follow conditions:seed age is 48h, inoculation volume is 3mL/30mL, temp is 28℃, rotate speed is 150r/min. For cultured 85h after optimization, the cellulase activity of strain H57-1 reach 23.19U/mL which has risen 41.3%.