Feasibility of nanocrystalline cellulose production by endoglucanase treatment of natural bast fibers

Whereas straw management presents a continuing challenge among farmers, tremendous opportunities may exist within the natural fibers in terms of value- added products or chemicals. This research provides the first assessment and demonstration of feasibility of an enzyme-assisted production of nanocrystalline cellulose (NCC) from hemp and flax fibers. A newly cloned endoglucanase (AoEG), derived from Aspergillus oryzae and characterized to be a thermostable enzyme with a half-life of 50 h at 50 °C was used for the hydrolysis. Atomic force microscopy (AFM) imaging of NCC produced from acid swollen cellulose and flax fibers indicated that they form aggregated network, showing rod-like nanofibrils of about 10 nm in height, and 200 nm in length. The yield of NCC using physical pretreatment only or combined physical-chemical pretreatment was compared. The highest yield of NCC was obtained under the conditions of 300 mg of flax fiber treated by 100 IU enzyme at 50 °C for 24 h after pretreatment of the fibers by sonication-microwave in 2% NaOH solution.