Enzyme Applications in Pulp and Paper Manufacturing

Transcription

1 Enzyme Applications in Pulp and Paper Manufacturing Mike Paice Lakehead University Symposium September 27, Paprican 1

2 utline Background on status of biotech in P&P Enzymes in Kraft pulping Enzymes in newsprint manufacturing 2005 Paprican 2

3 Member Companies Prince George Field Station McGill and Ecole Polytechnique Vancouver Lab UBC P&P Center Pointe-Claire Lab 2005 Paprican 3

4 Biotreatment Systems in Canadian Mills Activated sludge: 70 Conventional: 48 xygen (AS): 12 SBR: 10 Aerated stabilization basin: 34 Anaerobic (UASB): 2 Attached growth: 3 FPAC Survey, Paprican 4

5 Large-scale Biotechnology! 2005 Paprican 5

6 Status of Biotechnology Effluent biotreatment is well established technology Some innovation in process design and biomass monitoring Small byproduct industry based on fermentation (biorefinery) Enzyme technologies for manufacturing are growing in number and volume 2005 Paprican 6

7 Enzyme Applications Kraft pulp bleaching Biomechanical pulping Extractives & stickies control Pectinase for paper machine retention Deinking of mixed office waste Improved drainage Microbial control Catalase for peroxide removal 2005 Paprican 7

8 Kraft Pulp Enzyme Bleaching: Current Situation About 10% of North American kraft pulp production is bleached with xylanase Increased BD load to effluent treatment is reported What is yield loss, and can it be prevented? ther hydrolytic enzymes may also save bleaching chemicals 2005 Paprican 8

9 Xylanase Bleaching Enzyme addition Check effluent load: BD/CD D Eop D D Ep D Monitor xylose release 2005 Paprican 9

10 Softwood Bleaching Curve Xylanase 88 Final Brightness, % IS Control Savings 12.1% Total, Cl 2 kg/t 2005 Paprican 10

11 Pulp Bleaching = Lignin Removal 2 2 Cellulose Hemicellu lo se Lignin 2 Cellulose 5 nm 2005 Paprican 11

12 Yield Loss Versus Effluent Load 25 Increase in BD and CD, kg/t Softwood Softwood- 2 low NaH Hardwood A low NaH Softwood- 2 CD (R 2 =0.84) BD (R 2 =0.88) Hardwood A Hardwood B Yield Loss, % 2005 Paprican 12

13 Finding a Better Enzyme [ Xylose 4--methylglucuronic acid (10:1-10:3) Xylose Xylose Xylose Xylose Xylose ] n 6 CH CH 5 H 3 C 4 H [Xylose]n Kraft pulping - CH 3 H [Xylose]n H H 2005 Paprican 13

14 Xylanase Accessory Enzymes Feruloyl esterase Appl Microbiol Biotechnol.62: (2003) Arabinofuranosidases Biotechnol. Advances 18, (2000) Glucuronidase & hexenuronidase US Patent 6,830,655 (2004) to VTT 2005 Paprican 14

15 Kraft Pulp Bleaching Summary Yield loss of between 0.4 (softwood) and 1.0% (hardwood) Correlation between yield loss and increased effluent BD/CD Extraction stages can be optimized to minimize losses ther enzymes may provide higher specificity 2005 Paprican 15

16 New Enzymatic Approach to Reduce Refining Energy 2005 Paprican 16

17 Thermomechanical Pulping Separates fibers in wood or wood chips by mechanical friction force for newsprint and other paper grades Energy intensive process: kw/h per ton of TMP produced ver 60% of refining energy is consumed for fiber separation 2005 Paprican 17

18 Refining Process in a TMP Mill Primary refiner Wood chips Impregnation Mainline TMP To bleaching Latency chest Screening Rejects refiners 2005 Paprican 18

19 Potential for Enzymes to Reduce Mechanical Pulping Energy Fiber cell wall swelling prior to mechanical refining would enhance fiber separation and reduce energy Cell wall-loosening protein: Expansin Specifically disrupts non-covalent bonding (e.g. H-bond) Reduces crystallinity of cellulose Creates cell wall expansion without hydrolysis 2005 Paprican 19

20 The Action of Expansin on Cell Wall 2005 Paprican 20

21 Potential Fungal Enzymes for Cell Wall Swelling Recently, fungal expansin swollenin has been identified Several commercial cellulases have demonstrated ability to swell fiber Pretreatment of wood chips by these enzymes may provide savings in refining energy 2005 Paprican 21

22 Approach Applying enzymes in chip impregnation to maximize the absorption of enzyme into the intracellular structure of wood chips Examine the potential for energy savings and quality improvements Some positive results seen previously with cellobiohydrolase, pectinase, xylanase 2005 Paprican 22

23 Enzyme Impregnation of Wood Chips Wood chips Compression chamber (compress ratio up to 6:1) Impregnation with enzymes 2005 Paprican 23

24 Extractives and Stickies Control 2005 Paprican 24

25 Wood Extractives ver one thousand different compounds Including resin acids, fatty acids, sterols, lignans, triglycerides etc. Lipophilic extractives: e.g. fatty acids and triglycerides Hydrophilic extractives: e.g. lignans 4-10% (w/w) on wood, 2-5% (w/w) on pulp Cause pitch deposition, reduce paper strength properties, and impair paper surface properties 2005 Paprican 25

26 Background Lipase for pitch control Hydrolyze triglycerides to fatty acids Little decrease in total extractives content New problems associated with extractives in pulp and paper Lower coefficient of friction reduces the printing ability of paper (slippery paper) Caused by lipophilic extractives: fatty acids and triglycerides 2005 Paprican 26

27 Esterase, Lipase: Pitch Control Benefits: Hydrolyses triglycerides, steryl esters Reduces problems caused by pitch deposition on air foils, machine wires, forming fabrics, Uhle boxes, press section, improves runnability Improves friction of paper Improved tensile properties of paper 2005 Paprican 27

28 Measures to Alleviate Friction Problems Wood chip seasoning Not practical for Canadian mills in winter Chemical treatments Abrasive fillers: white carbon (synthetic silicate) High cost Enzymatic treatments Lipase has little effects xidative enzyme, laccase, shows promise to degrade lipophilic extractives and enhance paper friction 2005 Paprican 28

29 Interaction of Laccase/MnP with Residual Kraft Lignin Mn Peroxidase H 2 2 Cellulose Mn xalate ABTS Hemicellulose Lignin Laccase 2 Cellulose 5 nm 2005 Paprican 29

30 Laccase Catalyzed Reaction with Fatty Acid Esters C 5 H H Laccase (CH 2 ) 7 CR C 5 H 11 C 5 H 11. or. (CH 2 ) 7 CR (CH 2 ) 7 CR C 5 H 11 (CH 2 ) 7 CR 2 13 C 5 H C 5 H 11 Laccase 11 or aldehydes, ketones, alcohols etc.. 9 (CH 2 ) 7 CR 9 (CH 2 ) 7 CR R = H or alkyl 2005 Paprican 30

31 Laccase Treatment Showed Potential to Remove Extractives from Mechanical Pulp 100 Remaining extractives (%) U/g 5 U/g 25 U/g Paprican 31

32 Laccase Treatment Significantly Reduces Extractive Level in Paper Machine White Water 100 Remaining extractives (%) Total extractives Lipophilic extractives Hydrophilic extractives Paprican 32

33 Pectinase Treatment Reduces Cationic Demand Problem Alkaline peroxide bleaching of TMP dissolves polygalacturonic acid (pectin) resulting in: Pectinase Solution The enzyme pectinase depolymerizes polygalacturonic acid into smaller subunits resulting in: Increased cationic demand Decreased effectiveness of cationic additives Decreased cationic demand Increased effectiveness of cationic additives C - C - C - C - C - C - C - Pectinase C - C - C - C - C - C - C - H 2 H 2 H Paprican 33

34 Cationic Demand, meq/l Galacturonic Acid Degree of Polymerization Note: When the degree of polymerization of polygalacturonic acid (pectin) drops to below 5, the cationic demand of the pectin drops Paprican 34

35 Effect of Pectinase on Cationic Demand Cationic Demand, meq/l Time, minutes 2005 Paprican 35

36 Cationic Demand vs. FPR First Pass Retention, % Cationic Demand, meq/l 2005 Paprican 36

37 Papermachine Retention 2005 Paprican 37

38 Enzymes for Deinking Cellulase, hemicellulase (xylanase, mannanase) Helps dislodge ink from fibers, improves drainage Lipase, esterase Stickies removal, pitch removal Amylase Helps dislodge ink from starch coated papers 2005 Paprican 38

39 Summary Enzyme applications now well accepted Must be cost-effective Some limitations due to extremes of ph and temperature in processes Possible role in a future biorefinery industry 2005 Paprican 39

40 Acknowledgements Xiao Zhang Robert Bourbonnais Sylvie Renaud Michelle Ricard Buckman Canada Paprican Member Companies 2005 Paprican 40