Screening Of Endophytic Fungi Of Taxus Cuspidata S.et Z.for Specific Production Of Cellulase And Its Preliminary Application

Lignocellulosic biomass is the most abundant renewable resource in nature and the only renewable resource that can provide liquid,gas and solid fuel at the same time,and lignocellulose can also be used as raw material to produce a variety of products,has important economic benefits.In nature,cellulose degradation is mainly accomplished by microorganisms,which can produce cellulase,among which fungi are the most potential microorganisms for cellulose degradation.This study separate 164 strains from health root,stem and leaf of Taxus cuspidata S.et Z,and six strains which can degrade cellulose were obtained through preliminary screening by using cellulose Congo red culture medium,and through the determination of cellulose enzyme on the six strains after screen,select one of cellulose enzyme activity of the highest production strain,and combining the characteristics of morphology and molecular biology,has carried on the appraisal.The selected strain with the highest cellulase activity was optimized for enzyme production conditions,the degradation effect of cellulose on straw waste from Hibiseu manihot L.was investigated under the optimum conditions of enzyme production,it provides scientific basis for its application in degradation of agricultural and forestry waste.The results were as follows:1.A strain of endophytic fungus of Taxus cuspidata S.et Z cuspidate with the highest cellulase activity was screened and identified.R4,a strain of endophytic fungus of Taxus cuspidata S.et Z.cuspidate with high yield of cellulase was screened by means of the experiment of cellulose cone red transparent circle and the experiment of cellulase activity determination.In combination with morphology and molecular biology,R4 was identified as a strain of Penicillium oxalicum,and it was used as a follow-up experimental strain.2.The conditions of nitrogen source,pH,culture temperature and culture time were optimized,and the optimum fermentation and culture conditions for cellulase production by R4 were determined.The optimal process parameters are:Using PDB medium,1%waste straw powder of Hibiseu manihot L.was used as carbon source and ammonium sulfate as nitrogen source.The initial pH of fermentation was 5.0.The culture was conducted at 34? and 160 rpm for 77 h.The cellulase yield of endophytic fungus R4 was the highest,with FPase of 1.45 U/mL,CMCase of 5.27 U/mL,?-GLase of 6.34 U/mL.3.The effect of R4 on the degradation of cellulose in the straw waste of Hibiseu manihot L.was investigated.Under the condition of the liquid-solid ratio is 20:1(v/w),investigated and compared the effect of R4 degradation of cellulose.The results show that R4 for the degradation of cellulose is very effective,the degradation rate can reach 57.11%,the reducing sugar content of 26.95%,the FTIR results shows that partial internal functional groups of cellulose are damaged also suggests R4 has the ability of specific degradation of cellulose.In summary,this paper firstly screened and obtained an endophytic fungus of Taxus cuspidata S.et Z.that specifically degrades cellulose,and used it to treat cellulose in the straw powder of Hibiseu manihot L.,the raw material of natural lignocellulose.The degradation rate of cellulose was high and almost had no effect on hemicellulose and lignin.This method has the advantages of short time,mild reaction conditions,environmental protection,low cost and easy industrialization,etc.Therefore,the endophytic fungus R4 of Taxus cuspidata S.et Z.is a strain that is expected to be used in industry,providing a new idea for agricultural and forestry waste treatment.