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TAPPSA 2010

Influence of enzymes on refining of eucalyptus pulps Crystal Steel Francois Wolfaardt. TAPPSA 2010. Aim. Improve the refining of Eucalyptus grandis and E. nitens pulps using cellulases & hemicellulases. Why Eucalyptus grandis and E. nitens?. Eucalyptus grandis

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TAPPSA 2010

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  1. Influence of enzymes on refining of eucalyptus pulpsCrystal SteelFrancois Wolfaardt TAPPSA 2010

  2. Aim Improve the refining of Eucalyptus grandis and E. nitens pulps using cellulases & hemicellulases

  3. Why Eucalyptus grandis and E. nitens? • Eucalyptus grandis • Traditional wood timer source • Expansion of pulp & paper industry increased need for more land, which were at higher altitudes • E. nitens was grown due to cold tolerance • Eucalyptus nitens • Grows fast & adaptable • Good quality fibre • Smaller fibres & thinner cell walls • High tensile, bulk density, opacity and brightness Slide 4

  4. Introduction: Refining of wood pulp fibres Refining pulp fibres Cutting Fibrillation & fines De-curling Fibre swelling Improved bonding & reduced pulp freeness Increased effective length & sheet formation Increased bonding & strength of fibres Reduced fibre length

  5. Hemicellulose Reducing end Non-reducing end Crystalline cellulose Amorphous cellulose Introduction: Enzymes • Hemicellulase • Xylanase (X) (HW) • Cellulases • Endoglucanase (EG) • Cellobiohydrolase (CBH) X EG CBHII CBHI

  6. 1µm Refining with enzymes Untreated Treated 1µm Hardwood pulp samples treated with endoglucanase on commercial scale with refining.

  7. Introduction: Refining with enzymes Enzyme refining of pulp fibres Cutting ? Fibrillation & fines ? De-curling ? Fibre swelling ?

  8. Method: Pilot scale refining • 3% pulp consistency • Enzymes: 0.02g protein/ kg pulp • Endoglucanase, Cellobiohydrolase & Xylanase • Sample before incubation, at 20 min & at each refining energy: • E. grandis 24.9, 49.2, 73.1, 96.5 & 119.4 kWh/t • E. nitens 21.5, 42.3, 62.6, 82.2 & 101.3 kWh/t Slide 9

  9. Method: Sample analysis Pulp Freeness (CSF) Water retention value (WRV) Paper Tensile strength Tear strength Bulk density Porosity 20 cm Slide 10

  10. Results : E. grandis & E. nitens refining curves E. nitens E. grandis

  11. Results and Discussion Control @ 450 ml

  12. Results: Xylanase

  13. Results: Xylanase

  14. Results: Endoglucanase

  15. Results: Endoglucanase

  16. Results: Cellobiohydrolase

  17. Results: Cellobiohydrolase ?

  18. Conclusions • Enzymes affected properties in a similar way on the two HW species • Most noted change with enzymes were: • Xylanase on E. nitens with a 75% reduction in porosity • EG on E. grandis with a 50% improvement in tensile • CBH on E. grandis with 12% increase in tear and 20% increase in tensile • The enzymes have better improvements on E. grandis than E. nitens

  19. General Conclusion • Enzymes do improve pulp properties • HOWEVER • Enzymes are specific in their activity on different pulps • Specific properties need to be targeted possibly at the expense of others

  20. Acknowledgements • Sappi Manufacturing • UKZN – EM Unit • Genencor, Novozymes and AB Enzymes

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