1. A Presentation on
CRITICAL REVIEW
OF
“Indigo Dyeing of Polyamide Using Enzymes for Dye Reduction”
Mojca Bozic and Vanja Kokol
Institute of Engineering Materials and Design, University of Maribor
Smetanova ulica 17, SI-2000 Maribor, Slovenia
Georg M. Guebitz
Institute of Environmental Biotechnology, Graz University of Technology Petersgasse 12, A-8010 Graz, Austria
Published in Textile Research Journal 2009
BY
Sareweshwra Nand Pandey
UNDER THE GUIDANCE OF
Prof. (Dr.) R. V. ADIVAREKAR
2. INTRODUCTION
This presentation gives a summary of eco-friendly processes for the reduction of
vat dyes. Classical processes of indigo dyeing use sodium dithionite as reducing
agent, causing enormous environmental problems.
In this paper, a new process of indigo reduction using NADH- dependent
reductases from Bacillus subtilis in the presence of redox mediators is presented.
The efficiency of mediated enzymatic indigo reduction on the dyeing of
polyamides 6 and 6,6 was studied at 60°C, pH 7 and 11.
The authors have done an excellent work regarding environmental protection by
crude NADH-dependent reductases isolated from Bacillus subtilis for reduction of
indigo (C.I. Vat Blue 1) into its soluble form.
Successful reuse of the enzyme have confirmed by authors.
4. Chemicals
The authors have used following Chemicals in their study:-
Indigo (Fluka)
1,8-dihydroxy-9,10-anthraquinone (Aldrich)
NADH (β-nicotinamide adenine dinucleotide disodium salt) (Aldrich)
NaOH (Aldrich)
Na2S2O4 (Aldrich) as reducing agent
H2O2 (Aldrich) as the oxidizing agent
Crude enzymes (25–50 mg/ml of protein content as determined using the Lowry
method) were isolated from B. subtilis
Nitrogen was employed for deaeration.
Materials
The authors have used commercial polyamide 6,6 (95.6 g/m2,6.4 dtex) and
polyamide 6 (0.5 g/m2, 9.2 dtex) fabrics prepared for dyeing throughout the work.
5. Redox PotentialDetermination
Redox potentials of Na2S2O4 (5 g/l at pH 11) and indigo reductases from B.
subtilis without and with mediator (12.5 µM) in phosphate buffer solution (pH 4–
12) at different temperatures (25–65 °C) have monitored for 65 minutes by authors.
The authors have used a pH meter (Mettler Toledo MA 235, pH/Ion Analyser)
for the measurements.
8. Reuse of mediatedenzymatic dyeingbath
The authors have carried out reusing of mediated enzymatic dyeing bath according to the
following procedure:
After polyamide material was enzymatically mediated dyed at selected pH and 60°C for
90 minutes, the polyamide was removed from the dye bath
The new polyamide sample was placed in the remained mediated enzymatic-bath with the
addition of starting indigo concentration and lost buffer.
After 90 minutes of the dyeing the procedure was repeated again with the new set of
polyamide sample.
conventionaldyeingof polyamides
The authors have carried out conventional dyeing of polyamides using:-
1 gm Na2S2O4 as reducing agent per 1.5mg of indigo according to the standard dyeing
procedure, with 80:1 liquor ratio at both pH (Tris-HCl; pH 7 and Tris-NaOH; pH11).
9. Determinationof Colour and Colour Fastness properties
The authors have determined the colour of the dyed fabrics from the reflectance
measurements using Spectraflash SF 600 PLUS spectrophotometer (Data colour) at
standard illuminant D65 using a 10° observer. The colour was evaluated by
CIELAB colour co-ordinates (L*, a*, b*, C* and h) and colour depth (K/S) was
calculated using the Kubelka-Munk equation: K/S = (1-R)2/2R
The authors have determined colour fastness to washing, light, alkaline and acid
perspiration using standards ISO 105-C04, ISO 150-B04, and ISO 105-E04,
respectively.
10. RESULTSANDDISCUSSION
Conditions for mediated enzymatic indigo reduction
The influence of mediator 1,8-dihydroxy-9,10-anthraquinone on the reduction
potential of reductases
CIELAB colour values of differently indigo-dyed PA6 and PA6,6
Colour yield values of polyamide 6 and PA 6,6
The absorption properties of indigo in the case of mediated enzymatic dyeing
Effect of the dyeing time and pH medium on colour strength of enzymatically
mediated indigo dyed polyamides
Effect of the indigo concentration and pH medium on colour strength
Effect of the mediated enzymatic reduction system reusing On colour strength
Wash, perspiration and light fastness properties of chemically and enzymatically
mediated indigo-dyed PA6 and PA6,6
11. temperatures for mediated enzymatic indigo reduction
Indigo-reductases activity at pHs 7 and 11 versus different
temperatures
14. Table 2 CIELABcolour valuesof differentlyindigo-dyedPA6 and PA6,6after90 minutesof dyeing (0.16% owf) at 60 °Cand
pH 11.
15. Colour yield values of polyamide 6
Effect of the dyeing pH medium (pH 7 and 11) on colour depth of chemically
and enzymatically (with and without mediator) dyed PA6 after 90 minutes.
16. Colour yield values of polyamide 6,6
Effect of the dyeing pH medium (pH 7 and 11) on color depth of chemically and
enzymatically (with and without mediator) dyed PA6,6 after 90 minutes.
18. Effectof thedyeingtimeandpH mediumoncolorstrengthof enzymaticallymediatedindigodyedpolyamides
Effect of the dyeing time and pH medium on color strength of enzymatically mediated
indigo (0.16% owf) dyed polyamides after 90 minutes of dyeing at 60 °C.
19. Effect of the indigo concentration and pH mediumon colour strength
Effect of the indigo concentration and pH medium on colour strength of
polyamides dyed enzymatically mediated at 60 C for 90min.
20. Effect of the indigo concentration and pH mediumon colour strength
Effect of the indigo concentration and pH medium on color Strength of
polyamides dyed Chemically at 60 °C for 90 minutes
23. Wash,perspirationandlightfastnesspropertiesof chemicallyandenzymaticallymediatedindigo-dyedPA6and
PA6,6
Table show Wash, perspiration and light fastness properties of chemically and enzymatically mediated
indigo-dyed PA6 and PA6,6 after 90 minutes of dyeing (0.16 owf) at 60 °C and pH 7 after soaping.
Table show Wash, perspiration and light fastness properties of chemically and enzymatically mediated
indigo-dyed PA6 and PA6,6 after 90 minutes of dyeing (0.16 owf) at 60 °C and pH 11 after soaping
24. CONCLUSIONS
Reductases from B. subtilis could substitute sodium dithionite in indigo dyeing in
the presence of mediator 1,8-dihydroxy-9,10-anthraquinone.
Dyeing experiments gave very good fastness properties for acid and alkali
perspiration, and satisfying results for wash and light fastness properties.
These results indicate that mediated enzymatic indigo reduction process could be
of significant interest in terms of economically and ecologically competitive
dyeing technology compared to actual chemical indigo reducing system.
In addition, with consideration of sensitiveness to the pH value, enzyme
mediated reduction system can be applied to recycle use at pH 11.
However, further work is required to establish the redox chemistry of the enzyme
mediated indigo reduction in order to optimize the process, as well as trying to
transfer it to other types of vat dyes requiring higher reduction potential.
26. Titleand Abstract
The authors have given sufficient data in abstract about their research work. They
have given a summary of eco-friendly processes for the reduction and oxidation of vat
dyes with a short and good content.
The title “Indigo Dyeing of Polyamide Using Enzymes for Dye Reduction” and
abstract gives brief idea about theme of paper.
Introduction
Authors have explained very clearly about introduction part. In the introduction part
authors has discussed about the importance of eco-friendly reducing agents in today’s
era because of the environmental problems caused by sulfur-based byproducts (i.e.
sulfites, sulfates, sulfur, etc.) formed in the decomposition of sodium dithionite and
high pH generated in a well manner.
As far as introduction is concerned authors has touched various aspects of the Indigo
Dyeing of Polyamide Using Enzymes for Dye Reduction topic.
27. Technicalcorrectness
Authors have listed experimental chemicals in sufficient detail but Authors had
not given any reference for the selection of particular chemical concentration,
temperature and time in their paper. They should have mentioned the
characteristics and other standard parameters of the chemicals they have taken for
process.
The authors have not given enough information regarding the materials used. they
should have mentioned the quality of the fabric in detail like the construction
parameters epi, ppi. In substrate details regarding polyamide authors didn’t mention
the polyamide substrate specification in detail. The sample size selected is not
mentioned and it is very difficult to carry out further testing.
In their study authors have restricted himself to C.I. Vat blue 1 as far as the dye
ability part is concerned. On contrary they should have carried out the same
experiment for all other dyes also.
28. Technicalcorrectness………
Authors should have included fastness tests like, multiple washing testing like
(EN ISO 6330:2002) and abrasion resistance (EN ISO 7854:2000) for assessing
true picture of fabric performance.
Commercial chemical used for performing the experiments were without further
purification. The result could have been obtained well if the authors followed the
process of purification.
The authors have shown redox reaction mechanism of indigo for better
understanding.
The authors have not subdivided results and discussions although authors have
discussed the results of these parameters neatly and clearly.
Authors have given test procedure which is understandable; but they have not
mention the test method procedure in detail.
29. Clarity
In this paper authors have explained the background of work first, in which they
have discussed the importance of the work, its usage and some previous work on
this subject. Introduction to the area of research and its significance are well
discussed and gives a clear idea about the theme of the paper.
The paper is made with simple and easy language.
The authors have organized the paper in a good step by step manner.
Easily understandable terms.
Introduction, Experimental, Results, Discussion & Conclusions are mentioned clearly.
Tables and graphs have been individually discussed clearly.
The paper sticks to the subject. Therefore paper is reasonably easy to follow and
understand.
Authors have lacked clarity in writing the procedure for dyeing of polyamide with vat
dyes in conventional method.
The some aspects like the vattsing procedure, sample size, chemical characteristics are
missed out.
30. Illustrations/Tables/Graphs
The research work and experiments are summarized in tabulated and
graphical manner by authors in which they have given direct relation between
the parameter and testing results.
All graphs and table have explained clearly. Particularly all the parameters are
explained.
There are 4 tables and 17 figures including graphs in complete paper. All of
them are neat and without any mistakes.
All the information and details are distinguishly presented in the graph and
table.
The graphs and tables illustrated in this manuscript are very well explained.
The graphical and tabulate representation of all the data results obtained from
the experiments are very well interpreted and necessary for understanding.
31. BIBLIOGRAPHY
The authors have mentioned thirty seven main references. Almost all the
references have been cited in their work.
The Research paper references are quite a good in numbers.
All of the references reveals the required information about Indigo Dyeing of
Polyamide Using Enzymes for Dye Reduction.
All the references that have been cited are listed and vice versa. All the available
references are cross checked for the content and are found to be correct and in
agreement with what they have been cited for.
The authors have shown references in a well manner and the no. of references are
also good. Authors have mentioned references properly.
32. REFERENCES
1. Vuorema, A.,John, P., Keskitalo, M., Kulandainathan, M. A., and Marken, F.,
Electrochemical and Sonoelectrochemical Monitoring of Indigo Reduction by Glucose,
Dyes Pigm. 76,542–549 (2008).
2. The Journal of The Textile Institute Vol. 102, No. 1, January 2011, 87–92
3. Son, Y. A., Hong, J. P., and Kim, T. K., An Approach to the Dyeing of Polyester
Fibre Using Indigo and Its Extended Wash Fastness Properties, Dyes Pigm. 61, 263–272
(2004)
4. Son, Y. A., Lim, H. T., Hong, J. P., and Kim, T. K., Indigo Adsorption to Polyester
Fibres of Different Levels of Fineness, Dyes Pigm. 65, 137–143 (2005).
5. Burkinshaw, S. M., Chevli, S. N., and Marfell, D. J., The Dye- ing of Nylon 6,6 with
Sulphur Dyes, Dyes Pigm. 45, 65–74 (2000).
6. Burkinshaw, S. M., Lagonika, K., and Marfell, D. J., Sulphur Dyes on Nylon 6,6 –
Part2:the Effects of Reductant, Oxidant and Wash-off, Dyes Pigm.58, 157–170 (2003).
7. Burkinshaw, S. M., Lagonika, K.,and Marfell, D. J., Sulphur Dyes on Nylon 6,6 –
Part 1: the Effect of Temperature and pH on Dyeing, Dyes Pigm. 56, 251–259 (2003).
8. Burkinshaw, S. M.,and Lagonika, K., Sulphur Dyes on Nylon6,6 – Part 3: Preliminary
Studies of the Nature of Dye-fibre Interaction, Dyes Pigm. 69, 185–191 (2006).
33. REFERENCES………..
9. Baumgarte, U., Developments in Vat Dyes and Their Applica- tion 1974–1986, Rev. Prog.
Colour. 17, 29–38 (1987).
10. Grull, D. R., Begli, A. H.,Kubadinow, N., Kunz, M., and Munir, M., Process for
Reducing Sulphur and Vat Dyes, U.S. Patent 6,093,221 (1999).
11. Roessler, A.,and Crettenand, D., Direct Electrochemical Reduction of Vat Dyes in a Fixed
Bed of Graphite Granules, Dyes Pigm. 63, 29–37 (2004).
12 .Roessler, A.,New Electrochemical Methods for the Reduction of Vat Dyes, Dissertation
No. 15120, Swiss Federal Insti- tute of Technology, Zurich, Switzerland (2003).
13. Božic M.,and Kokol, V., Ecological Alternatives to the Reduction and Oxidation
Processes in Dyeing with Vat and Sul- phur Dyes, Dyes Pigm. 76, 299–309 (2008).
14. Pricelius, S., Held, C., Sollner, S., Deller, S., Murkovic, M., Ullrich, R., Hofrichter, M.,
Cavaco-Paulo, A., Macheroux,P.,and Guebitz, G. M., Enzymatic Reduction and Oxidation of
Fibre-bound Azo-dyes, Enzyme Microb. Technol. 40, 1732–1738 (2007).
15. Lowry O. H., Rosebrough, N. J., Farr, A. L., and Randall, R.J., Protein Measurement
with the Folin Phenol Reagent, J. Biol. Chem. 193, 265–275 (1951).
16. Pricelius,S.,Held, C., Murkovic, M., Bozic, M., Kokol, V. Cavaco-Paulo, A., and Guebitz,
G. M., Enzymatic Reduction of Azo and Indigoid Compounds, Appl. Microbiol.
Biotechnol.77, 321–327 (2007).
