sign in sign up
<<
Home , Cellulase, Fiber modification, Sizing, Substrate (printing), Xylanase

Enzyme Applications in and : An Introduction to Applications

Dr. Richard Venditti

Associate Professor - Director of Graduate Programs Department of and Paper Science Biltmore Hall Room 1204 Raleigh NC 27695-8005 Tel. (919) 515-6185 Fax. (919) 515-6302 Email: [email protected]

Slides courtesy of Phil Hoekstra. Endo-Beta 1,4

• Are proteins that catalyze chemical reactions • Biological cells need enzymes to perform needed functions • The starting molecules that enzymes process are called substrates and these are converted to products

Endo-Beta 1,4 Xylanase which acts on substrate to make product of .

Endo-Beta 1,4 Xylanase Enzymes

• Are extremely selective for specific substrates • Activity affected by inhibitors, pH, temperature, concentration of substrate • Commercial enzyme products are typically mixtures of different enzymes, the enzymes often complement the activity of one another

Endo-Beta 1,4 Xylanase Types of Enzymes in Pulp and Paper and Respective Substrates • --- • Cellulase --- cellulose fibers • Protease --- proteins • Hemicellulases(Xylanase) --- • Lipase --- glycerol backbone, pitch • Esterase --- esters, stickies • Pectinase --- pectins

Endo-Beta 1,4 Xylanase Enzyme Applications in Pulp and Paper • Treat for paper applications • Enhanced bleaching • Treatment for pitch • Enhanced • Treatment for stickies in • Removal of fines • Reduce refining energy • Cleans white water systems • Improve softness in tissue • Clean outs

Endo-Beta 1,4 Xylanase Starch Conversion for Surface Coatings

• are used to cleave starch molecules to reduce the viscosity • Used for surface sizing and for starch in coatings • Not used for dry strength agent additive

Endo-Beta 1,4 Xylanase Bleaching

• Hemicellulases () are used to cleave in fiber, making the bleaching process more effective • May be able to reduce bleaching chemicals by up to 30% • Can improve brightness

Endo-Beta 1,4 Xylanase Pitch treatment

• Lipases used to control pitch in pulping processes • Converts tri-glycerides to fatty acids which are more stable in water, won’t deposit as much

Endo-Beta 1,4 Xylanase CH2 –------CH –------CH2 Triglycerides

OOO Ester-Bonds C=O C=O C=O

(CH2)15 CH3 (CH2)15 CH3 (CH2)15 CH3 glycerol Fatty acids CH2 –------CH –------CH2 │ OH OH OH OH │ C=O │

(CH2)15 CH3

Endo-Beta 1,4 Xylanase Deinking

• Paper recycling and stickies attach to fibers at the surface of the fibers, stuck to microfibrils • Cellulase and hemicellulase enzymes hydrolyze these microfibrils, releasing the adhesives • Esterases help breakdown particles • Enzyme assisted DI reported to remove 30-60% more toners • Enzyme assisted DI reported to improve brightness by 4-5 points

Endo-Beta 1,4 Xylanase Control and Removal Methods for Stickies

– Use of environmentally benign adhesive (recyclable adhesive) – Avoidance: Control of recovered paper quality – Mechanical removal: screening and water clarification – Chemical control: surfactants, others – Passivation with inorganics – Enzyme – Physical adsorption to paper fibers: retention – Dispersion – Protection: treatment of equipment to limit deposits – Mill shut down for clean-up

Endo-Beta 1,4 Xylanase CLASSIFICATION OF STICKIES

PRIMARY SECONDARY (Formed in (Change in pulper) environment, pH, temp., etc.)

Endo-Beta 1,4 Xylanase MACRO VS MICRO STICKIES

Macrostickies Retained on 6-cut (0.15 mm) slotted screen* Microstickies Accepted by 6-cut (0.15 mm) slotted screen* * Trend is towards 0.10 mm or 0.075 mm slottedEndo-Beta screen 1,4 Xylanase Stickies Control

• Microstickies in dilution water recirculate back into the systems • Microstickies agglomerate under shear and pH changes and contribute to macrostickies, secondary stickies • Reducing microstickies will make a significant impact on macrostickies • Ability to measure both micro and macro is important

Endo-Beta 1,4 Xylanase Endo-Beta 1,4 Xylanase Without Proper Water Clarification (<20% reduction): “ re-introduction of stickies”

Endo-Beta 1,4 Xylanase Enzymes as stickies treatment

• Esterases used to break ester bonds in polymers used in toners and adhesives • Improved paper cleanliness • Less deposits, less clean up on PM • Can be used as substitute for talc or solvent based dispersants

Endo-Beta 1,4 Xylanase -(CH2 – CH - CH2 –CH -CH2 – CH )n - PVAc OOO Ester-Bonds C=O C=O C=O

CH3 CH3 CH3

PVAlcohol Acetic acid

-(CH2 – CH )- CH2 –CH -CH2 – CH )n - │ OH OH OH OH │ C=O │

CH3

Endo-Beta 1,4 Xylanase polyvinyl acetate Hydrophobic Surface -(-CH2CH-)n-

OCOCH3 without Esterase with Esterase

Agglomerates of PVAc

polyvinyl alcohol + acetic acid

-(-CH CH-)n- OH 2 OH HO OH HO OH OH OH OH OH + CH COOH OH HO 3 HO OH OH OH OH OH HO OH OH OH HO OH OH OH OH OH OH OH OH HO OH OH OH OH OH OH OH HO OH OH OH OH HO Polyvinyl alcohol OH OH OH OH OH

Hydrophilic Endo-Beta 1,4 Xylanase Impact on stickies chemistry

• Optimyze has two impacts on stickies – Cleaves ester bonds to reduce size of stickies – Surfaces on smaller stickies are converted to alcohol groups • Alcohol groups are less tacky • Alcohol groups are polar, which allow DAF polymers to grab onto them for removal

Endo-Beta 1,4 Xylanase Electron micrographs

Untreated Treated

Endo-Beta 1,4 Xylanase Optimyze Plus 735 trial data

stickies transfer on reel samples during Optimyze Plus 735 evaluation

count 160 PPM 1.2 140 BLX dosage 1 120

100 0.8

80 0.6 stickies 60 0.4 40 BLX 13064dosage (lb/t)

20 0.2

0 0

2/12 3/4 3/24 4/13 5/3 5/23 Endo-Beta 1,4 Xylanase Caustic replacement: neutral deinking for deinking • Caustic is used in pulping recycled fibers to swell fibers, improving paper making potential • Cellulase enzymes can be used in conjunction with or as a substitute for the caustic to swell fibers • Neutral deinking has some advantages including less COD in the white water, lower costs

Endo-Beta 1,4 Xylanase Decrease energy in refining

• Cellulase enzymes cause partial depolymerization of cellulose and swelling of fibers, more flexible fibers • Reduction of fines • Improves efficiency of refining, can decrease energy consumption or obtain improved strength at higher freeness • Often better runnability or less dryer energy required

Endo-Beta 1,4 Xylanase Fibrillation

3/3/2010 Endo-Beta 1,4 Xylanase Fiber Modification

• Enzymes can assist this de-lamination process • Conditions fiber for refining • Reduces refining energy • Changes the refining curve • Old rules do not apply • Laboratory Testing

Endo-Beta 1,4 Xylanase Case History

• MILL: Quebec • FIBER: Recycled/Softwood Kraft • GRADE: Napkin • GOAL: Increase tensile strength to middle of specification, reduce kraft fiber usage • METHODS: Treated MOW stock at the pulper with 0.5 to 1.0 kg/tonne BZM 2545, about 3 hours of contact time

Endo-Beta 1,4 Xylanase Machine Trial of Buzyme 2545 in Napkin grade 45 275

40 270 35

30 265

25 SWK Usage 260 Tensile 20 Kraft Usage (%) Usage Kraft Tensile Strength Tensile 15 255

10 250 5

0 245 Pre-trial Trial

Endo-Beta 1,4 Xylanase Machine Trial of Buzyme 2545 in Napkin grade

25 300

250 20

200

15

SWK Usage 150 Tensile

10 Kraft Usage (%) Usage Kraft Tensile Strength Tensile 100

5 50

0 0 Pre-trial Trial

Refining energy reduced

Endo-Beta 1,4 Xylanase Results: Machine Trial of Buzyme 2545 in Napkin grade • Reduced kraft from 40% to 0% of furnish • Increased tensile to a “comfortable” range • Refining energy reduced 14% • Drainage is better, but cannot take advantage of it, due to drive limitations

Endo-Beta 1,4 Xylanase Hydrolysis of fines

• Fines build up in water loop in PM and cause drainage, formation and paper properties problems • Cellulase enzymes hydrolyze these fines, making them soluble, improving PM ops • Can run PM faster (up to 10% faster in some cases?)

Endo-Beta 1,4 Xylanase Softness in tissue

• Cellulase enzymes improve softness by hydrolyzing cellulose in fibers, creating weak spots in fibers, making fibers flexible • Softness increases of up to 25% • P&G has several patents, some donated to NCSU

Endo-Beta 1,4 Xylanase Case History

• MILL: Quebec • FIBER: 95% SWD/5% Recycled Fiber • GRADE: Premium Bath • GOAL: Reduce refining energy, increase softness and bulk, maintain tensile • METHODS: Treated stock at the pulper with 0.5 to 1.0 kg/tonne BZM 2545, about 3 hours of contact time

Endo-Beta 1,4 Xylanase Bulk vs. Tensile Buzyme 2535 vs. Glyoxylated Polyacrylamide

11

Average Bulk to Tensile 10 Increase of 3.5%

9 B/BW

8

7 12 14 16 18 20 22 GMT/BW Buzyme 2535 Gloxylated PAM Linear (Buzyme 2535) Linear (Gloxylated PAM)Endo-Beta 1,4 Xylanase Results

• Shut down refiners • Maintained tensile • Bulk/basis weight increased by avg. of 3.5% • Able to reduce BWT due to increase in tensile • Machine speed increase of 100 FPM, due to better drainage

Endo-Beta 1,4 Xylanase ROI for Fiber Modification • Reduction in refiner energy • Less fines generation – Better drainage – Softer feel – Less dusting – Cleaner white water • Reduction in starch or CMC • Fiber substitution – Could use more MOW, less virgin

Endo-Beta 1,4 Xylanase Improved biodegradability of pulp mill waste water • and Hemicellulases used to degrade cellulose and other high molecular weight polymers • COD/BOD ratio of domestic sewage 2:1 • COD/BOD ratio of waste water up to 5:1 • Hydrolysis of cellulose fines by enzymes to lower molecular weight sugars that are more biodegradable

Endo-Beta 1,4 Xylanase Clean Ups / Boil Outs

• Amylase to treat starch deposits in clean ups of starch preparation/application equipment • Protease used as biodispersants or enzyme boil-outs, cleave protein molecules in deposits and solubilize deposits

Endo-Beta 1,4 Xylanase Summary

• Enzymes are green chemicals that can improve operations in pulp and paper • Wide variety of enzymes, must be applied with understanding of how they work • Several widely accepted applications, starch, bleaching, clean ups • Future: high valued functionalized fibers, improved pulping, specialized paper properties, conversion of wastes to fermentable sugars.

Endo-Beta 1,4 Xylanase