Combining water-soaking, ionic liquid, and electron beam irradiation pretreatments for enzymatic hydrolysis of cellulose

Abstract

Pretreating lignocellulosic biomass (LB) is an important step before breaking it down with enzymes to use as biofuel. Researchers looked at how well electron beam irradiation (EBI) pretreatment works on microcrystalline cellulose (MCC), which is a type of cellulose found in LB, using doses between 100 and 1000 kGy. The effectiveness of EBI pretreatment on MCC was measured using the lateral order index (LOI) for samples soaked in water, samples not soaked in water, and samples soaked in an ionic liquid (IL). The combination of the water solvent with EBI led to a greater LOI reduction percentage effectiveness (LOI%) of 25.40% for the water-soaked samples, while the samples treated with 50% (v/v) 1-ethyl-3-methylimidazolium acetate [EMIM]Ac as the IL alone showed a reduction of only 20.25%, and the non-soaked samples had a reduction of just 14.84%. However, EBI, water soaking, and IL pretreatments further reduced the LOI of MCC. In addition to this, significant ANOVA overall linear regression equation models (representing a p-value < 0.05) for each of the EBI-MCC non-soaked, water-soaked and IL pretreatments were also reported. The MCC linear predictive equation from the EBI water-soaked method was validated using oil palm frond with the same approach, and it was found to be overestimated, with a Root Mean Squared Error (RMSE) of about 8%. In conclusion, significant prospects for EBI or [EMIM]Ac, which offer balanced techno-economic feasibility when replacing water solvent during the pretreatment of MCC representing LB, are only possible if the RMSE value indicates a higher accuracy between predicted and actual values of the crystalline state of LB. These findings open a new perspective on EBI-combinatorial pretreatment for future cost reduction.