Research On Cellulase Immobilization And The Effect Of Enzymatic Hydrolysis For Anerobic Degistion

Cellulose could be hydrolyzed into reducing sugar by cellulase and it is an effictive method to make the biomass reasource efficient utilization.However,cellulase could mix into cellulase hydrolysis system,which reduced the purity of the product and cellulase run off.And the activity of cellulase is sensitive to pH and tempreture.In order to make the cellulase easily to be separated from enzymatic hydrolysis system and enhance the stability of the cellulase,in this study cellulase was immobilized and to analysis the properties of the immobilized cellulase.Then,the effect of the immobilized cellulase enzymatic hydrolysis was determined.The method of cellulase immobilization was studied by analyse the effect and propertries of immobilized cellulase.Optimal conditions of SA immobilized cellulase:cellulase concentration,the ratio of 3.5%(w/w)SA solution and 1%(w/w)glutaraldehyde,cross-linking time,CaCl2 concentration,immobilized tempreture,immobilized time was 5 mg/mL,1:1.5,4 h,2%,50 ? and 2.5 h,respectively.Add PEG into SA immobilized cellulase prepared SA-PEG immobilized cellulase,which the ratio of SA and PEG was 1:2.5(w:w),the immobilized yield increased 18%.Then,coated with CS for 30 minutes,the immobilized yield increased 16%.After 5 reuse cycles,the relative activity of SA-PEG-CS immonilized cellulzse was 60%.The stability of properties of the three immobilized cellulase was better than free cellulase.MCC was hydrolyzed by immobilized cellulase and determined the effects of the immobilized cellulase hydrolysis.The optimal conditions of enzymatic hydrolysis MCC:SA immobilized cellulase loading?substrate concentration and pH was 3.57 g/g TS substrate,4.60%and 5.13,respectively.SA-PEG immobilized cellulase loading,substrate concentration and pH was 3.55 g/g TS substrate,13.16%and 5.11,respectively.SA-PEG-CS immobilized cellulase loading,substrate concentration and pH was 3.49 g/g TS substrate,6.89%and 4.93,respectively.Compared with SA immobilized cellulase,the effect of MCC hydrolyzed by SA-PEG immobilied cellulase and SA-PEG-CS immobilized cellulase increased 133.08%and 133.84%,respectively.The overall reducing sugar yield maximum enchanced 22.68%of the three immobilized cellulase in the reusable cycles.After the enzymatic hydrolysis,the structure of MCC changed obviously and the crystallization area was increased.Corn stalk pre-treatmented by NaOH was hydrolyzed by immolized cellulase to determin the effects of enzymatic hydrolysis.After the enzymatic hydrolysis,BMP test of the corn stalk was measured.The optimal conditions of conren stalk hydrolysed by three immobilized cellulase was same:immobilized cellulase loading?substrate particle size?substrate concentration and pH was 3.5 g/g TS substrate,100-300 mesh,5.0%and 5.0,respectively.Compared with SA immobilized cellulase,the effect of corn stalk hydrolyzed by SA-PEG immobilized cellulase and SA-PEG-CS immobilized cellulase increased 16.26%and 17.40%,respectively.The overall reducing sugar yield maximum enchanced 41.07%of the three immobilized cellulase in the reusable cycles.The cost of immobilized cellulase hysrolysis reduced.The structure of corn stalk changed obviously after the pre-treatment and enzymatic hydrolysis.The accumulate methane production which was pretreated by NaOH + immobilized cellulase(334 mL/g VS-338 mL/g VS)was closed with treated by NaOH + free cellulase(365 mL/g VS)and compared with NaOH pretreated,the accumulate methane production increased 14%-15%.Thus,it has the positive effect of corn stalk for anerobic digrstion hydrolyzed by immobilized cellulase.In summary,cellulase immobilized by SA-PEG-CS was the best one,immobilized by SA-PEG was the second.