Preparation and characterization of the spherical nanosized cellulose by the enzymatic hydrolysis of pulp fibers

•The spherical NC can be obtained from the enzymolysis of pulp fibers.•The efficiency of complex enzymes is higher than single cellulase in the process.•The pulp fiber can effectively be swelled by glycerol.•The synergetic action of xylanase may be due to its hydrolysis to the hemicellulose.•The reaction time is shorten from several days to several hours. In this work, the pulp fibers were enzymolyzed to prepare the nanosized cellulose (NC). The as-prepared samples were characterized by optical microscopy, electron microscopy, and Raman spectra. The experimental results indicated that enzymatic hydrolysis of pulp fibers could produce the spherical NC with a mean particle size of about 30nm, which had the excellent monodispersity and uniformity. When the concentration of complex enzymes was 20u/mL (cellulase: xylanase=9: 1), the yield of NC was 13.6%. The single cellulase was used, even if the enzyme concentration reached up to 200u/mL, only a mixture of strip and granular flocculation were obtained. The positive synergistic effect between xylanase and cellulase could be due to the enzymolysis of hemicellulose located on the cellulose microfibers to be favorable of cutting and splitting of the microfibers by the endoglucanase in cellulase.