An Auspicious Application of Laccase and Hydrogen Peroxidases for Biobleaching of Recalcitrant Paper Dyes

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1 An Auspicious Application of Laccase and Hydrogen Peroxidases for Biobleaching of Recalcitrant Paper Dyes Kristina Knutson and Arthur Ragauskas, Institute of Paper Science and Technology, Atlanta, GA

2 % Recycled Recycling Continues to Increase >90% linerboard >80% newsprint >60% white office ledger <30% mixed office waste 81 million tons of waste fiber in US in 1994

3 Research Objectives Test effectiveness of virgin pulp biobleaching technologies on color removal from dyed pulps + Enzyme

4 Today s s Talk Dyes Direct Yellow 11 & Basazol 46L Measurement of Color Laccase & peroxidases Peroxidases experimental results Laccase experimental results Summary

5 Recycling Colored Papers Raw Material Type Mixed Office Waste Colored Ledger File Stock Goldenrod Brightness After Treatment Original Deinked Formamidine sulfinic acid (FAS) 0.5% Hydrogen Peroxide 1% Hydrosulfite (Dithionite) 2% Reference: Ferguson, L.D TAPPI Deinking Short Course Bleaching Wastepaper

6 Structure Direct Yellow 11 Structure most problematical dye commonly used for office paper

7 Structure Basic Dye Baszol 46L United States Patent Number 4,256,458 March 17, 1981 Methine Dyes for Paper and Amonically-Modified Fibers Patent applies to methine dyes of the formula 2A- A is an organic or inorganic ion R is hydrogen, methyl or ethyl Q groups are the same or different substituted or unsubstituted aryl or hetaryl radicals X represents a bridge member selected from the group consisting of aliphatic, aromatic and heteroaromatic radicals. Structure of most common yellow dye used in directory paper

8 Example Dye

9 Structure Direct Yellow 11

10 Example Spectra ph8.5 No PEG+B40 Con Absorbance Wavelength

11 CIELAB Color Space

12 Calculation of Dye Removal Index Distance from Ideal Bleach Point = R 2 L=100 a=b=0 R 2 R 1 a = b = L = 0 R 2 = a 2 + b 2 + (100-L) 2 Amount of Color Removal = - R 2 R 2 = R 22 R 1 2 R 2 = (a 22 a 12 ) + (b 22 b 12 ) + [(100-L 2 ) 2 (100-L 1 ) 2 ] Dye Removal Index (DRI) = -100 [ R 2 / R 12 ] DRI = Percent Color Removed by the Treatment

13 Potential of Biobleaching Recycled Fiber O H 3 C C N OH MEDIATOR

14 Oxidation of ß-O-4 4 lignin dimer I by laccase/hbt system

15 Peroxidase Catalytic Cycle Clear applications for color destruction that have not yet been examined

16 Experimental Results

17 Horseradish Peroxidase System 2 hour Reaction at 45 C 100mM Acetate buffer, ph mM Veratryl alcohol 10ppm Dye 5 Units Horseradish peroxidase /ml 0.1 mm Hydrogen peroxide

18 Peroxidase Decolorizes Basic Dye HRP Treatment Absorbance Basazol 46L Treated Basl 46L Direct Yellow 11 Treated Yellow Wavelength (nm)

19 Soybean Peroxidase System 2 hour Reaction at 45 C 100mM Acetate buffer, ph mM Veratryl alcohol 0.1M Calcium chloride 10ppm Dye 1 Units Soybean peroxidase /ml 0.1 mm Hydrogen peroxide

20 Comparison of SBP and HRP % Reduction in Abs Area Direct Yellow 11 Basazol 46L SBP HRP

21 SBP Effective Over Wide Ph Range SBP Treat ph PEG % Dec. PEG % Dec. PEG % Dec. Basazol 46L 2.4 Non e K K

22 Laccase-Mediator System For Treating Dyed Pulp 2 hour Reaction at 45 C 10bar Oxygen pressure 100mM Acetate buffer, ph 4.5 Mediator mM 5mM 50 µkat/ml Laccase 10ppm Direct Yellow 11 or 3% pulp consistency

23 Laccase Mediators Mediator Name HBT 1-Hydroxy benzotriazole Violuric acid Mediator Structure O NOH O N N N OH HN NH O ABTS 2,2'azinobis-3-ethyl ethyl- benzthiazoline-5- sulfonate HO 3 S S N N N S N H 2 C CH 3 H 3 C CH 2 SO 3 H

24 Dissolved Direct Yellow 11 + LMS Absorbance Dye, 1 mm HBT, Lac, to Dye, HBT, Lac, 2hr 45 C, 10bar O ppm Direct Yellow Wavelength, nm

25 Effectiveness of LMS Decolorization Depends on Mediator Mediator Comparison DRI (Dye Removal Index) Lac+HBT Lac+VA Lac+ABTS

26 ABTS Effective at Low Concentration Dose Dependence DRI (Dye Removal Index) mm ABTS

27 Post-LMS Reaction Liquid Phase Effluents from Treated Pulps 1 Absorbance White Pulp + Lac+0.1mM ABTS Dyed Pulp + Lac+0.1mM ABTS Wavelength (nm)

28 Laccase + ABTS Direct Yellow 11 + Laccase + ABTS After 2hr at 10bar O 2, 45 ºC Purified Direct Yellow 11

29 Conclusion Laccase/ABTS system can decolorize stilbene dye Direct Yellow 11 Peroxidases are ineffective for Direct Yellow 11 Peroxidases do decolorize basic dye Basazol 46L Laccase decolorizes Basazol 46L