Optimization of the Production of Amorphous Cellulose with High Enzymatic Hydrolysis

Abstract The method for production of amorphous cellulose (AC) by the treatment of initial cellulose material (MCC and mixed waste paper) with a cold solvent containing 7% NaOH and 12% urea has been studied at different solvent to cellulose ratios (R, mL/g). Using X-ray diffraction, it was shown that the MCC treatment at R = 3 resulted in a transformation of the crystalline modification (CM) CI of the initial cellulose into CM CII characterized by a low crystallinity degree. In the case of R ≥ 5, the treatment process resulted in a formation of completely amorphous cellulose (AC). Due to its high hydrolyzability, the AC substrate with a concentration of 50 g/L is almost completely converted into glucose within 48 h under the action of the CTec-3 enzyme preparation with a dose of 30 mg/g of dry substrate. The obtained AC sample can be used as an amorphous standard for the study of the crystallinity and enzymatic hydrolysis of various types of cellulose and lignocellulose. The enzymatic saccharification of AC was found to be the most beneficial with the substrate concentration raised to 150 g/L. Due to a high cost of MCC, a low-cost raw material, such as mixed waste paper, is preferable for use in the industrial production of ACC and glucose.