Research On Enzymatic Hydrolysis Of Arundo Donax Using Crude Cellulase From Penicillium And Comercial Cellulases

Cellulosic material is renewable resource. The transformation andutilization of cellulose resource has broad prospect and application value.Enzymatic hydrolysis is one of the key steps. In this paper,one-factor-at-a-time (OFAT) experiments and central composite design(CCD) according to the principles of response surface methodology(RSM) was arried out to optimize the enzymatic hydrolysis process ofsolids from pretreatment of Arundo donax by steam explosion, providingcertain theory basis for saccharification and fermentation of Arundodonax to produce ethanol and butanol.The optimum fermentation time for the production of cellulosefrom Penicillium JU-A10was studied. And the effects of temperature,reacting time, pH and cellulase loading on enzymatic hydrolysisefficiencies were discussed. The results indicated that the optimumfermentation time for the production of cellulosefrom Penicillium JU-A10was96hours, and the suitable conditions forenzymatic hydrolysis of Arundo donax were:45℃of reactiontemperature, pH value of4.8and30FPU/gDM of cellulase loading for72hours hydrolysis. Under these conditions the glucose yield was61.75%,and the xylose yield was40.07%. The sugar yields could be furtherincreased after xylanase and β-glucosidase supplement. The glucose yieldof68.96%and xylose yield of98.16%could be reached when theβ-glucosidase was increased to40CBU/gDM.The effects of the cellulose loadings of NS50013, NS50010andXylanase on enzymatic hydrolysis efficiencies of Arundo donax werestudied. Based on the10FPU/gDM and20FPU/gDM of NS50013cellulase loadings, commercial enzyme NS50010and Xylanase weremixed with NS50013in different proportions. The results indicated thatthe glucose yield of66.89%and xylose yield of74.31%was achievedunder the condition of10FPU/gDM of NS50013cellulase loading, 10CBU/gDM of NS50010cellulase loading and100IU/gDM of Xylanaseloading after enzymatic hydrolysis for72hours,while there was a6.19%increase in glucose yield and a8.53%increase in xylose yieldrespectively. And the glucose yield of74.03%and xylose yield of77.32%was achieved under the condition of20FPU/gDM of NS50013cellulase loading,20CBU/gDM of NS50010cellulase loading and200IU/gDM of Xylanase loading after enzymatichydrolysis for72hours,while there was a13.77%increase inglucose yield and a2.96%increase in xylose yield respectively. Theabove results demonstrated that under the same conditions of substrateconcentration and enzyme composition, the glucose yield could beincreased in a degree by increasing the cellulase loading of NS50013within a certain range.In order to improve the enzymatic hydrolysis efficiency of Arundodonax, central composite design was used to investigate the effects ofenzyme loadings of NS50013, NS50010and Xylanase on glucose yield.The results indicated that the glucose yield increased with the increasingof the cellulase loading of NS50013and Xylanase respectively.Meanwhile the cellulase loading of NS50010had no obvious effect. Theoptimal composition of the cocktail mixture was30FPU/gDM ofNS50013cellulase loading,7CBU/gDM of NS50010cellulase loadingand109.97IU/gDM of Xylanase loading. Under these condition theexpected glucose yield was75.49%compared with the experimentalglucose yield was74.68%.