Methyl methacrylate(MMA) was grafted onto microcrystalline cellulose(MCC) with ceric ammonium nitrate(CAN) as a redox initiator at the various conditions. The cellulose triacetate(CTA) composite films added MCC and MMA-grafted MCC powders were prepared on a glass plate. The graft yield(GY) and graft efficiency(GE) of the grafted MCC were calculated with the simple equations by the weight balance method. The double bond of C=O on the grafted MCC surfaces was confirmed by the fourier transform infrared spectroscopy with attenuated total reflection(FT-IT ATR) spectrophotometer. After grafting, the degree of crystallinity of cellulose powders was decresed by judging from x-ray diffraction(XRD) data. Scanning electron microscope(SEM) photos showed the only solvent and CAN solution could change the roughness of MCC powders and the effect of powder dispersions in composite matrix. The tensile strength of MCC/CTA composite films was decreased with increase of MCC powder contents. When 5% grafted MCC was added, the tensile strength of grafted MCC/CTA composite films was increased from 82.3 MPa to 97.2 MPa. The thermal property of powders was also analyzed by the thermogravimetric analysis(TGA).

In this study, microcrystalline cellulose, which is a cell wall polysaccharide commonly contained in sea algae (brown algae, red algae and green algae), is used in substitution for cellulose and is hydrolyzed with seven enzymes available in the market. The seven enzymes selected are Viscozyme® L, Celluclast® 1.5 L, Saczyme, Novozym® 33095, Fungamyl® 800 L, Driselase® Basidiomycetes sp., and Alginate Lyase. To maximize the production of the reducing sugar by hydrolysis with each enzyme, we optimized the quantity of enzymes, reaction time, pH, and reaction temperature as four independent variables, and the reducing sugar production rate as a dependent variable, utilizing response surface methodology (RSM) to optimize the enzyme hydrolysis reaction conditions. Among the tested enzymes, the production rate of reducing sugar by Celluclast® 1.5 L was the highest. Hence, the predicted optimum conditions (8.5 % enzyme, reaction time 27.6 h, pH 4.1 and reaction temperature 44.1oC) were directly applied to Laminaria japonica and proved the predicted optimum conditions with experiments. Under the optimum conditions, the sugar yield of 137.6 mg/g-Laminaria japonica (experimental value) was obtained.