Screening Of Cellulose-degrading Microorganisms And Study Of Conditions For High-efficiency Cellulase Activity

Cellulose is the most abundant renewable resource in nature.Cellulase is the key to degrading cellulose into glucose that can be utilized.Screening high-efficiency cellulose-degrading strains and promoting higher cellulase activity are the main topics of current research.In this paper,the experimental methods of cellulase activity were optimized,and the specific experimental conditions and methods for the activity of cellulose carboxymethyl cellulose(CMC-Na)and the activity of filter paper(FPA)were determined.High-efficiency cellulose-degrading strains were screened from the habitat and the optimal conditions and maximum enzyme activities were determined by factors such as dissolved oxygen,culture temperature,substrate concentration and bacterial inoculation.Through research,the following conclusions can be drawn:(1)Blank background treatment is an important factor affecting cellulase activity.The blank treatment is carried out by centrifugation of the bacterial liquid and then thorough sterilization at 121 0 C high temperature and high pressure.The hydrolysis temperature and hydrolysis time of CMC-Na activity were 50? and 30 min,respectively.The DNS dosage and boiling water bath time were 1.5 mL and 5 min,respectively.The hydrolysis temperature and hydrolysis time of FPA enzyme activity were 40? and 60 min,respectively.The boiling water bath time was 3.0 mL and 10 min,respectively.(2)There are many bacteria-degrading cellulose strains selected in the habitat,mainly Bacillus or Paenibacillus,but the overall activity is not high,and the FPA enzyme activity is lower than that of CMC-Na.The fungal strains are mainly of the genus Trichosporon,Alternaria and Trichoderma,and the CMC-Na enzyme activity is lower than that of the FPA.(3)The effects of various factors on the enzyme activity of the strain were determined by single factor experiments on dissolved oxygen,culture temperature,substrate concentration and inoculum.Dissolved oxygen has an effect on cellulase activity,and too high dissolved oxygen will affect cellulase activity.Culture temperature bacterial strains and fungal strains differ.The optimal culture temperature of the bacteria was 37?,and the optimum culture temperature of the fungus was 25 0 C.Within a certain range,the CMC-Na activity and FPA activity of cellulose-degrading strains showed an increasing trend with the increase of substrate concentration and inoculum.The optimum culture conditions for the cellulose bacteria strain were determined to be the shaking speed of 150r/min,the culture temperature of 37?,the substrate concentration of 2C,and the inoculum volume of 5mL.Under this condition,the cellulolytic bacteria strain secreted the most cellulase.The enzyme activity is the largest.The optimal conditions for fungal strains were shaking speed 150r/min,culture temperature 25?,substrate concentration 2C,and inoculum volume 5mL.Under this condition,cellulose degradation fungi strain secreted the most cellulase and the enzyme activity was the largest.