Cellulose is the most abundant biopolymer on Earth, syn-
thesized by a wide variety of living organisms as well as by
higher plants [1]. It is a linear homopolysaccharide, com-
posed of -1,4-linked glucans with a high level of sym-
metry in an amphiphilic molecular structure. Interchain
hydrogen bonding makes cellulose crystalline and there-
fore insoluble in water, and intrachain hydrogen bonding
makes it stiff. The crystallite (or microfibril) in the cel-
lulose texture excludes water molecules and is crucial for
physicochemical stability.
The water-soluble nature of cellulose, on the other
hand, is necessary for organisms to live in aqueous envi-
ronments. The affinity to water is closely related to amor-
phous domains, hierarchically organized in the cellulose
texture, where amorphous refers to a space occupied by
the cellulose swollen by water or by pure water. Micro-
scopic and crystallographic examinations of cellulose mi-
crofibrils from different organisms have revealed that the
size of microfibrils varies greatly among different organ-
isms