Eucalyptus biokraft pulping process

Abstract

In a new process for preparing pulped wood chips for paper making, chips from a hardwood such as eucalyptus are inoculated with a living culture of one or more white rot fungi. The fungi propagate throughout the body of the wood chip, selectively attacking the lignin of the wood without harming the cellulosic fibers. Subsequent kraft pulping with standard chemicals results in less chemical usage, reduced utilization of energy, improved strength, and reduced cooking time.

We claim:  
     
         1 . A method for producing paper pulp for use in the making of paper from eucalyptus wood chips, comprising in the steps of: 
 a) inoculating the wood chips with white rot fungi;    b) fermenting the wood chips so as to cause a propagation of the fungus through the wood chips and allow the fungus to modify lignin; and    c) pulping the degraded wood chips by a known kraft process.    
     
     
         2 . A method as claimed in  claim 1  together with the further step of bleaching the kraft pulp by a known multistage bleaching process.  
     
     
         3 . Canceled.  
     
     
         4 . A method as claimed in  claim 1  wherein the fermentation step is a static fermentation step.  
     
     
         5 . A method as claimed in  claim 1  wherein the white rot fungus is  C. subvermispora.    
     
     
         6 . A method as claimed in  claim 5  wherein the  C. subvermispora  is a strain selected from the group consisting of: L-14807-SS-3, CZ-3, FP-105752-SS-5, FP-10572 and L-9186-SP.  
     
     
         7 . A method as claimed in  claim 1  wherein said white rot fungus is  Hyphodontia setulosa.    
     
     
         8 . A method as claimed in  claim 1  wherein said white rot fungus is  Phlebia subserialis.    
     
     
         9 . A method as claimed in  claim 1  wherein said white rot fungus is  Phlebia brevispora.    
     
     
         10 . A method as claimed in  claim 1  wherein said white rot fungus is  Phlebia tremellosa.    
     
     
         11 . A method claimed in  claim 1  wherein said white rot fungus is  Phanerochaete chrysosporium.    
     
     
         12 . A method as claimed in  claim 1  wherein the wood chips are inoculated with the fungus and without nutrients.  
     
     
         13 . A method as claimed in  claim 1  wherein the wood chips are inoculated with the fungus and known nutrients.  
     
     
         14 . A method as claimed in  claim 1  wherein the moisture content of the chips prior to the step of inoculation is kept at fibre saturation point or greater.  
     
     
         15 . A method as claimed in  claim 1  wherein said moisture content is 50-55% of the total wood based on a wet weight of the chips.  
     
     
         16 . A method as claimed in  claim 1  wherein the wood chips are inoculated with 1 to 5 gms inoculum/ton of wood.  
     
     
         17 . A method as claimed in  claim 1  wherein the moisture content in the wood during the step of fermentation is 55-65%.  
     
     
         18 . Biotreated eucalyptus wood chips for kraft pulping prepared by the process comprising 
 inoculating the eucalyptus wood chips with white rot fungi, and    fermenting the wood chips so as to cause propagation of the fungus through the wood chips and obtain chemically modified lignin.    
     
     
         19 . A method as claimed in  claim 1 , further comprising making paper from pulp produced in step (c).