Cj. Jacobs-young et al., Conventional kraft pulping using enzyme pretreatment technology: role of diffusivity in enhancing pulp uniformity, PAP PUU, 82(2), 2000, pp. 114-119
Kraft delignification of acetone extracted southern pine chips was enhanced
by enzyme pretreatment with a cellulase/hemicellulase/pectinase mixture. T
he increased delignification was attributed to the enhanced transport proce
sses in wood as a result of enzymatic hydrolysis. The chips were impregnate
d with the enzyme solutions after vacuum evacuation. Treatment was for 24 h
at 50 degrees C and pH 4.8. In chips thicker than 4 mm, enzyme pretreated
pulps had higher screened yields than the control pulp. Reject levels of pu
lps resulting from enzyme pretreatment were lower than resultant pulps from
control chips with similar thickness profiles. A kraft pulping model that
considers the combined effects of diffusion and chemical reaction was used
to simulate the pulping study and predict other final pulp properties. The
model results showed that the improvement in pulp uniformity was consistent
with the measured increase in diffusivity resulting from enzyme treatment.