Enzymatically Produced Nano-ordered Elements Containing Cellulose I_β Crystalline Domains of Cladophora Cellulose

Abstract

This chapter describes a novel top-down type extraction method of nano-cellulose using enzymatic hydrolysis of microcrystalline cellulose fibers comprising two crystalline allomorphs of cellulose, Iα and Iβ. In this method, the key issue was the selective removal of cellulose Iα phases by preferential hydrolysis of Trichoderma cellulase [1]. This selective hydrolysis process provided short elements having nanoscaled width. X-ray diffraction, electron diffraction, and FT-IR analyses revealed that the “nano-element” was highly crystalline, similar to the untreated microcrystalline cellulose, and mostly consisted of the Iβ phase. The average length of the elements was ca. 350 nm, which corresponded to the value due to the degree of polymerization of 690 for β-glucan molecular chains obtained by size-exclusion chromatographic analysis. The close agreement indicates that individual molecular chains may be extended in the longitudinal direction of the obtained element. These characteristic nano-elements have the potential to play a role of nano-ordered particles and may be useful as fillers to enhance the mechanical properties of various materials.