Isolation And Identification Of Cellulase Producing Strain Penicillium Janthinellum FDG4 And Its Degradation Of Straw

Lignocellulosic biomass is considered to be the most abundant,cheap and renewable raw materials.The production of commercial chemicals and biofuels from lignocellulosic biomass is gradually entering people's lives.However,due to the heterogeneity and obstinacy of lignocellulosic biomass,it is difficult to transform it into high value-added products.The complex structure of lignocellulose can be decomposed by effective pretreatment to improve the digestibility of cellulase.Pretreatment is very important for the degradation,transformation and efficient utilization of lignocellulosic biomass.In recent years,ILs has become an effective solvent for the treatment of lignocellulosic biomass,which provides an effective way for the pretreatment of biomass.Lignocellulose biomass was pretreated by ILs,and then further degraded by cellulase produced by fungi,bacteria and other microorganisms to sugars that can produce biofuels.Therefore,it is very important to select the high-yield cellulase strains with ionic liquid tolerance.In this study,the cellulase producing strains were isolated and screened.The cellulase activity of the strains and their tolerance to ionic liquids were measured.Strains with high cellulase production and cellulase tolerance of 5% 1-ethyl-3-methylimidazole acetate were screened out.The conditions of cellulase production were optimized,the optimal conditions of cellulase hydrolysis and the tolerance of ionic liquid were determined,and the hydrolysis effect of straw pretreated with ionic liquid was measured to obtain cellulase that can tolerate a certain concentration of ionic liquid.Through collecting soil samples,separating and purifying,screening and screening,a strain with high cellulase production and Its Cellulase can withstand a certain concentration of ionic liquid was obtained.After morphological analysis and molecular biological identification,it was named Penicillium janthinellum FDG 4.The optimum conditions of enzyme production were as follows: corn straw was the best carbon source and the amount of added was 1%,peptone was the best nitrogen source and the amount of added was 0.2%,The optimal initial p H was p H 4.0 at 2% inoculum,and the culture was conducted at 25? for 8 days,The FPase and CMCase of P.janthinellum FDG 4 were 0.11 U / m L and ?-glucosidase was 0.75 U / m L,respectively.The optimum p H and temperature of cellulase hydrolysis were determined,The results showed that the optimal p H value and hydrolysis temperature of P.janthinellum FDG 4 cellulase were 4.0 and 55?.The cellulase activity was FPase 0.12 U / m L,CMCase 0.25 U / m L and ?-glucosidase 0.79 U / m L,respectively.In the range of 0%-2.5% ILs,FPase and ?-glucosidase could still maintain 94% and 86% enzyme activity,When the concentration of ILs was 15%,FPase,CMCase and ?-glucosidase could still maintain more than 30% enzyme activity.The cellulase of strain P.janthinellum FDG 4 hydrolyzed the corn straw and the corn straw pretreated by ionic liquid for 72 hours,respectively,and produced 16.17 mg reducing sugar and 20.34 mg reducing sugar.The total yield of reducing sugar was 32.34% and 40.68% respectively.After 72 hours of commercial cellulase hydrolysis from Trichoderma reesei ATCC26921,21.03 mg of reducing sugar was produced,and the total yield of reducing sugar was 42.06%.The results showed that the corn straw pretreated by ILs had higher hydrolysis ability than that pretreated.It can be concluded that the cellulase liquid of P.janthinellum FDG 4 can be used to produce fermentable sugar,and then to produce biofuels or other high value-added products.