Journal of Chemical Technology and Biotechnology, Vol.83, No.9, 1261-1266, 2008
Enzyme-based approaches for pitch control in thermomechanical pulping of softwood and pitch removal in process water
BACKGROUND: In the pulp and paper manufacturing process, pitch colloidal particles have a tendency to agglomerate and deposit on pulp fibres and equipments. They reduce the efficiency of the washer, increase the dirt count and bleach chemical consumption, reduce pulp brightness thus leading to paper defects. Triglycerides are considered to be the most problematic compounds during the manufacturing of mechanical and acidic sulfite pulps from various softwood species. RESULTS: Using enzyme-based approaches, a pitch control method was developed for use with thermomechanical pulping of softwood and for pitch removal from process water. Results showed that with combination of a novel biodegradable surfactant and a lipase resin acids, sterols and triglyceride groups were reduced by 48%, 32% and 78%, respectively, compared with untreated samples. Using laccase treatment of the process water the fatty and resin acids were reduced by 42% and the lignans by 60%. CONCLUSION: By combining the proposed pulp treatment with laccase decontamination of the process water, this new method offers an efficient alternative to control the various pitch-associated problems. (C) 2008 Society of Chemical Industry.