(142e) Production of Laccase from Flammulina Velutipes and Its Application in Biobleaching of Kraft Bamboo Pulp

A laccase has been produced from Flammulina velutipes in liquid substrate fermentation using potato juice and glucose as the prime substrates. The nutrient conditions on the production of laccase, such as nitrogen sources and its amount, trace elements of Cu²⁺ and Mn²⁺, were optimized in this study. The maximum laccase yield is over 26 IU/mL. Combined with HBT, the laccase was applied to Totally Chlorine Free (TCF) and Elemental Chlorine Free (ECF) bleaching of Kraft bamboo pulps. The results indicated that Kraft bamboo pulps can be bleached to a brightness of 83.1 % ISO using TCF bleaching sequence and 85.8%ISO using ECF bleaching sequence in combination of LMS treatment. Also the physical properties of paper were improved after LMS bleaching. The ECF bleaching pulps had slightly lower burst index and tensile index, but higher brightness than those of the TCF bleached pulps. Also the enzyme-assisted bleaching before QP stage is proved to be more efficient than its use as a pre-bleaching agent.