Effects of a cellulase treatment on the preparation process and final properties of nanocrystalline cellulose

In this work, we introduced an enzymatic treatment with a cellulase prior to NCC isolation from fibers via sulfuric acid hydrolysis, combining biotechnological and chemical procedures. NCC isolation process has typically presented low yields, and because of this, finding alternative ways to increase the overall outcome would be very interesting. Two different sulfuric concentrations (62 and 64% wt.) were used. The effect of pore size for filtration step was also assessed. The smaller acid dose leaded to yields up to 65-70% and average size up to 160 nm. It also produced crystals with reduced sulfur content (0.6-1 %). We found that a cellulase pretreatment on fibers was capable of modifying the further fiber-acid interactions, as it increased NCC yield up to 11 %, increased NCC average particle size around 35 nm and reduced NCC sulfur content up to 0.8%. The evidence presented in this work suggested that the use of a cellulase represents a very promising biotechnological option for the partial replacement of harsh chemicals commonly used in this process