Separation and characterization of cellulose fibers from cypress wood treated with ionic liquid prior to laccase treatment

Separation of cellulose fibers (CFs) from woody biomass with minimal structural alteration using a
‘‘green’’ and efficient method was achieved by treatment with the ionic liquid (IL), [emim][OAc] (1-
ethyl-3-methylimidazolium acetate) at 80 �C for 1 h. The IL was recovered by rinsing with water–acetone
mixture prior to treatment of the wood with Trametes sp. laccase in the presence of 1-hydroxybenzotriazole
as a mediator. IL pretreatment did not significantly change the chemical composition of the wood,
but did alter its structure and rendered its surface more accessible to the enzyme. Treated and untreated
samples were characterized by SEM, FTIR, XRD, TGA, and chemical methods. The cellulose content of the
produced fibers was approximately 73.1% and the lignin content was 9.8%, much lower than the lignin
content of 29.3% of the untreated wood. The cellulose fibers exhibited higher cellulose crystallinity and
better thermal stability compared to untreated wood materials.