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Enzyme Applications in Pulp and Enzyme Applications in Pulp and Paper ManufacturingPaper Manufacturing
Mike PaiceLakehead University Symposium
September 27, 2005
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OutlineOutline
• Background on status of biotech in P&P• Enzymes in Kraft pulping• Enzymes in newsprint manufacturing
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Member Companies
Vancouver Lab
UBC P&P Center
Prince George Field Station
Pointe-Claire Lab
McGill and Ecole Polytechnique
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Biotreatment SystemsBiotreatment Systemsin Canadian Millsin Canadian Mills
• Activated sludge: 70– Conventional: 48– Oxygen (OAS): 12– SBR: 10
• Aerated stabilization basin: 34• Anaerobic (UASB): 2• Attached growth: 3
FPAC Survey, 1999
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LargeLarge--scale Biotechnology!scale Biotechnology!
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Status of BiotechnologyStatus 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
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Enzyme ApplicationsEnzyme 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
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Kraft Pulp Enzyme Bleaching: Kraft Pulp Enzyme Bleaching: Current SituationCurrent Situation
• About 10% of North American kraft pulp production is bleached with xylanase
• Increased BOD load to effluent treatment is reported
• What is yield loss, and can it be prevented?
• Other hydrolytic enzymes may also save bleaching chemicals
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Xylanase BleachingXylanase Bleaching
DEpEop DD D
Enzyme addition
Monitor xylose release
Check effluent load: BOD/COD
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Softwood Bleaching CurveSoftwood Bleaching Curve
17 18 19 20 21 22 23 24 25 26 27
82
83
84
85
86
87
88
89
90
Control
Xylanase
Savings 12.1%
Total, ClO2 kg/t
Fina
l Bri
ghtn
ess,
% IS
O
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Pulp Bleaching = Lignin RemovalPulp Bleaching = Lignin Removal
L ig n in
5 n mC e llu lo s e
H e m i-c e l lu lo s e
C e llu lo s e
2
2 2
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Yield Loss Versus Effluent LoadYield Loss Versus Effluent Load
0.4 0.5 0.6 0.7 0.8 0.9 1.0
0
5
10
15
20
25
BOD(R2=0.88)
COD(R2=0.84)
Softwood
Softwood-O2low NaOH
Hardwood Alow NaOH
Softwood-O2
Hardwood B
Hardwood A
Yield Loss, %
Incr
ease
in B
OD
and
CO
D, k
g/t
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Finding a Better EnzymeFinding a Better Enzyme
n][
4-O-methylglucuronic acid (10:1 - 10:3)
Xylose Xylose Xylose Xylose XyloseXylose
OH
O
OH3C
COOH
1
23
4
5
6
OHO [Xylose]n
O
COOH
OH
OH O [Xylose]n
Kraft pulping
- CH3O
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Xylanase “Accessory” EnzymesXylanase “Accessory” Enzymes
• Feruloyl esterase– Appl Microbiol Biotechnol.62: 349-355
(2003) • Arabinofuranosidases
– Biotechnol. Advances 18, 403-423 (2000)• Glucuronidase & hexenuronidase
– US Patent 6,830,655 (2004) to VTT
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Kraft Pulp Bleaching SummaryKraft Pulp Bleaching Summary
• Yield loss of between 0.4 (softwood) and 1.0% (hardwood)
• Correlation between yield loss and increased effluent BOD/COD
• Extraction stages can be optimized to minimize losses
• Other enzymes may provide higher specificity
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New Enzymatic Approach to New Enzymatic Approach to Reduce Refining EnergyReduce Refining Energy
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Thermomechanical PulpingThermomechanical Pulping
• Separates fibers in wood or wood chips by mechanical friction force for newsprint and other paper grades
• Energy intensive process: – 2000-3000 kW/h per ton of TMP produced
• Over 60% of refining energy is consumed for fiber separation
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Refining Process in a TMP MillRefining Process in a TMP Mill
Latency chest
Screening
To bleachingMainline TMP
Primary refiner
Rejects refiners
Wood chipsImpregnation
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Potential for Enzymes to Reduce Potential for Enzymes to Reduce Mechanical Pulping EnergyMechanical 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
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The Action of The Action of ExpansinExpansin on Cell Wallon Cell Wall
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Potential Fungal Enzymes for Potential Fungal Enzymes for Cell Wall SwellingCell 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
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ApproachApproach
• 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
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Enzyme Impregnation Enzyme Impregnation of Wood Chipsof Wood Chips
Compression chamber(compress ratio up to 6:1) Impregnation
with enzymes
Wood chips
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Extractives and Stickies ControlExtractives and Stickies Control
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Wood ExtractivesWood Extractives
• Over 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
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Background 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
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Esterase, Lipase: Pitch ControlEsterase, Lipase: Pitch ControlBenefits:• 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
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Measures to Alleviate Friction ProblemsMeasures 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– Oxidative enzyme, laccase, shows promise to degrade
lipophilic extractives and enhance paper friction
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Laccase
ABTS
Mn Peroxidase
Lignin
5 nmCellulose
Hemi-cellulose
Cellulose
O2
H O2 2
MnOxalate
Interaction of Laccase/Interaction of Laccase/MnPMnPwith Residual Kraft Ligninwith Residual Kraft Lignin
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Laccase Catalyzed Reaction with Laccase Catalyzed Reaction with Fatty Acid EstersFatty Acid Esters
Laccase
- H .
...... aldehydes, ketones, alcohols etc.
. or
.
.
(CH2)7COOR
C5H11
9
11
13
(CH2)7COOR
C5H11
9
11
13
.Laccase
O2
or
. (CH2)7COOR
C5H11
9
11
13
OO (CH2)7COOR
C5H11
9
11
13OO
R = H or alkyl
(CH2)7COOR
C5H11
9
11
13
(CH2)7COOR
C5H11
9
11
13
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Laccase Treatment Showed Potential to Remove Laccase Treatment Showed Potential to Remove Extractives from Mechanical PulpExtractives from Mechanical Pulp
50
60
70
80
90
100
1 U/g
25 U/g5 U/g
Rem
aini
ng e
xtra
ctiv
es (%
)
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Laccase Treatment Significantly Reduces Laccase Treatment Significantly Reduces Extractive Level in Paper Machine White WaterExtractive Level in Paper Machine White Water
0
5
20
40
60
80
100
Totalextractives
HydrophilicextractivesR
emai
ning
ext
ract
ives
(%)
Lipophilicextractives
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Problem SolutionAlkaline peroxide bleaching of TMP
dissolves polygalacturonic acid (pectin)
resulting in:
Increased cationic demand
Decreased effectiveness of cationic additives
Pectinase
O
COO-
O
O
COO-
O
O
COO-
O
O
COO-
O
O
COO-
O
O
COO-
O
O
COO-
O
O
CO O-
O
O
C OO-
O
O
C OO-
O
O
CO O-
O
O
C OO-
O
O
COO-
O
O
C OO-
O
H2 OH2 O H2 O
Pectinase
The enzyme pectinase depolymerizes
polygalacturonic acid into smaller subunits
resulting in:
Decreased cationic demand
Increased effectiveness of cationic additives
Pectinase Treatment Reduces Cationic DemandPectinase Treatment Reduces Cationic Demand
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1 10 1000
1
2
3
4
5
6
7
Galacturonic AcidDegree of Polymerization
Cat
ioni
c D
eman
d, m
eq/L
Note: When the degree of polymerization of polygalacturonic acid (pectin) drops to below 5, the cationic demand of the pectin drops.
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0 25 50 75 100
2
3
4
Time, minutes
Cat
ioni
c D
eman
d, m
eq/L
Effect of Pectinase on Cationic DemandEffect of Pectinase on Cationic Demand
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0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00
25
30
35
40
45
50
55
Cationic Demand, meq/L
Firs
t Pas
s R
eten
tion,
%
Cationic Demand vs. FPRCationic Demand vs. FPR
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Papermachine RetentionPapermachine Retention
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Enzymes for DeinkingEnzymes 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
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SummarySummary
• 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
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AcknowledgementsAcknowledgements
• Xiao Zhang• Robert Bourbonnais• Sylvie Renaud• Michelle Ricard• Buckman Canada• Paprican Member Companies