A Comparison of the Effects of Pretreatment with Xylanase and Laccase on Pulpabilities of Rice Straw

Rice straw was pretreated with xylanase and laccase respectively to improve the pulpabilities of rice straw pulps.The effect of different enzymatic dosages on results of enzyme pretreatment was investigated and the different effects of rice straw pretreatments with the above two enzymes on the pulpabilities were compared.The results indicated that rice straw pretreatments with xylanase or laccase improved pulpabilities of rice straw.The optimum enzymatic dosages were 20 IU/g for xylanase and 30 IU/g for laccase.Laccase was more effective than xylanase in the increases of pulp yield and pulp strength.Compared with unpretreatment straw pulp and xylanase treatment pulp,the yield of pretreated straw pulp with laccase increased by 13.11% and 8.79% respectively,the breaking length increased by 34.20% and 5.54% respectively,the bursting index increased by 23.81% and 7.22%,the tearing index increased by 78.59% and 3.26%.Xylanase pretreatment was better than laccase in the improvement of the pulp brightness.Compared with unpretreatment pulp and laccase treatment pulp,the britghtness of pretreated pulp with xylanase increased by 5.3 and 0.6 SBD units.