Effect of Laccase/Carbon Sources System Pretreatment on the Pulpability of Rice Straw

Rice straw was pretreated with Laccase/carbon sources system to improve its pulpability. The optimum condition of Laccase pretreatment, a comparison between Laccase/carbon sources system (LCS) and Laccase/mediator system (LMS), the effect of the pretreatment on AP-AQ cooking of rice straw were investigated. The results indicated that LCS can completely replace the expensive LMS for degrading the lignin in rice straw, the optimum conditions of pretreatment were pH value 5.0, temperature 45℃ ,liquor ratio 1∶7, pretreatment time 4～6 h, enzyme usage 20-30 IU/g.Compared with untreated straw, the pulp yield of straw pretreated with Laccase/carbon sources at enzyme usage 30 IU/g and pretreatment time 4 h increased by 4.6 points; the breaking length, bursting index and tearing index increased by 34.2%, 23.8%and 78.6% respectively; the brightness increased by 4.6 points.