© 2005 Paprican 1

Enzyme Applications in Pulp and Enzyme Applications in Pulp and Paper ManufacturingPaper Manufacturing

Mike PaiceLakehead University Symposium

September 27, 2005

© 2005 Paprican 2

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

© 2005 Paprican 4

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

© 2005 Paprican 7

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

© 2005 Paprican 8

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

© 2005 Paprican 13

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

© 2005 Paprican 26

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

© 2005 Paprican 39

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

© 2005 Paprican 40

AcknowledgementsAcknowledgements

• Xiao Zhang• Robert Bourbonnais• Sylvie Renaud• Michelle Ricard• Buckman Canada• Paprican Member Companies