Pretreatment by Ceriporiopsis subvesmispora and Phlebia subserialis of wheat straw and its impact on subsequent soda­AQ and kraft­AQ pulping

Abstract

Pretreatments  of  wheat  straw  with  two  different  lignin­degrading  fungal  cultures  ­ Ceriporiopsis subvesmispora and Phlebia subserialis­ were carried out and their effects on soda­AQ and kraft­AQ pulping were studied. After two weeks of bio­treatment of the wheat straw, both fungus were found to  be  suitable for  bio­chemical  pulping.  The fungal  pretreatment  decreased the  kappa number by as much as 24% and the unbleached pulp brightness increased by about 7% at a constant yield. Furthermore, the bio­pretreatment increased the brightness of the fully bleached pulp by about 1 ISO% point. This can apparently reduce the amount of the chemicals used in the bleaching process. The  results  on the  sugar  analysis  of the  pulps  showed that in terms  of  carbohydrate  composition, there  were  no  significant  differences  between  the  bio­treated  and  control  pulps.  However,  the strength properties of the un­bleached and bleached chemical straw pulps decreased slightly after the fungal pretreatment. This is different from reported results that the strength properties of mechanical pulps  were  improved  after  the fungal  pre­treatment.  There  was  no  difference  of  the  two  white­rot fungal  species, Ceriporiopsis  subvesmispora  and  Phlebia  subserialis in term  of their  effect  on the strength properties.