Effect of fungi on dyes used in making Nigerian tie and dye cloths ('Adire') and shelf-life determination

Dye quality and fastness properties could only be guaranteed for a finite period of time on shelf. In this study, the shelf-life of natural indigo dye and indigo VAT dye was studied for 360 days. Physico-chemical parameters monitored includes; total viable count, viscosity, pH, specific gravity, absorbance and transmittance from 360 days. Fungi isolated from the dyes on shelf were Achaetomium strumarium, Aspergillus niger, Aspergillus flavus, Duitina rugosa, Penicillium citrinum and Peyronellaea prosopidis. The fungal population count was monitored monthly throughout the shelf-life study period. Multiple linear regression model was used to predict the shelf-life of the dyes from the growth data of the isolated organisms and the physico-chemical parameters. The total fungal viable counts ranged from 1.267×105 -3.213×105 spores ml-1 for indigo VAT dye and 1.453×105 - 3.347×105 spores ml-1 for natural indigo dye over the 12 months study period. The changes in the physico-chemical parameters ranged from pH 12.94±0.00-10.39±0.01 and 12.54±0.00-10.01±0.01, specific gravity 1.279±0.00-1.106±0.005 and 1.445±0.00-1.176±0.001, viscosity 1.288±0.00-1.215±0.001 cSt and 1.283±0.00- 1.176±0.001 cSt, optical density 1.627±0.002-3.323±0.001 and 1.705±0.001- 3.315±0.002, transmittance 5.573±0.003-2.652±0.001 and 6.124±0.002-2.108±0.001 for indigo VAT dye and natural indigo dye respectively. The percentage dye exhaustion of the shelf-life products determined after the study period peaked at 88±0.001 and 90±0.001 % for indigo VAT dye and natural indigo dye respectively. The shelf-life were found to be 17 months and 10 months for indigo VAT dye and natural indigo dye respectively. The synthetic indigo VAT dye has a higher shelf-life than the natural indigo dye. Imported indigo VAT dye is however recommended based on its longer shelf-life. The results further buttressed the trend where textile dyers in Nigeria and indeed the West African region largely employ imported indigo VAT dye than locally produced natural indigo dye.Keywords: Shelf-life; Nigerian tie and dye cloths 'Adire'; indigo VAT dye; natural indig

Adapting vat dye as an alternate dyeing agent for vegetable tanned leather

The research explores the use of vat dye, a selected dye that is available locally in the Ghanaian market in large quantities, with varied colour ranges to identify their suitability as effective colourants on vegetable tanned leather. Four different experiments were performed with vat dye, and two others were tried with suede dye. In the first experiment, a more familiar technique ofapplying vat dye on fabric was used; this resulted in the burning of the exposed areas of the leather. For the second experiment, a new formula was composed and applied. This experiment was subdivided into three parts where various techniques for applying dyes were used. It proved successful, thus indicating that, with proper formulation, vat dye and its accompanying agents could perform effectively on protein fibre in leatherwork, just as it does on cellulose fibre in textiles

Understanding the economic influence of the dyeing industry in Pompeii through the application of experimental archaeology and thermodynamics

YesThe influence of the dyeing industry in Pompeii on the local economy has been under discussion since the publication by Moeller in 1976. Since no absolute answer has emerged, the question was re-examined using two additional methods, experimental archaeology and the principles of thermodynamics. A full-scale replica of a dyeing apparatus from Pompeii was constructed and used to simulate repeated dye runs, and so determine operating parameters such as the times involved to heat and cool a vat and the consumables needed. This first replica also allowed a better understanding of how the apparatus was actually used. Thermodynamic principles, which were applied to understand the successes and failures within the experimental work, suggested that the vat operated in a predictable way and enabled the operational mechanics of the vat to be established. It is now possible to use both the experimental results and the thermodynamic modelling to determine not just the consumables used, but also the working environment needed for the vat to operate, allowing an understanding of the limitations to dyeing and to workers. Issues of practicality such as storage of consumables and disposal of exhaust gases may now be thoroughly examined. 2 Eventually it will be possible to determine the operating parameters of each of the dye vats, the quantities of consumables involved and the amount that could be produced. This should help answer the question as to the significance of the dye industry in Pompeii to the local economy

Freeform Fabrication of Biological Scaffolds by Projection Photopolymerization

This article presents a micro-manufacturing method for direct, projection printing of 3- dimensional (3D) scaffolds for applications in the field of tissue engineering by using a digital micro-mirror-array device (DMD) in a layer-by-layer process. Multi-layered scaffolds are microfabricated using curable materials through an ultraviolet (UV) photopolymerization process. The pre-patterned UV light is projected onto the photocurable polymer solution by creating the “photomask” design with graphic software. Poly (ethylene glycol) diacrylate (PEGDA), is mixed with a small amount of dye (0.3 wt %) to enhance the fabrication resolution of the scaffold. The DMD fabrication system is equipped with a purging mechanism to prevent the accumulation of oligomer, which could interfere with the feature resolution of previously polymerized layers. The surfaces of the pre-designed, multi-layered scaffold are covalently conjugated with fibronectin for efficient cellular attachment. Our results show that murine marrow-derived progenitor cells successfully attached to fibronectin-modified scaffolds.Mechanical Engineerin

Dyeing of cotton with vat dyes using alkaline catalase alongwith iron(II) salt

In this study, attempts have been made to replace sodium hydrosulphite with alkaline catalase in combination with iron(II) salt for dyeing cotton with vat dyes. The results show that alkaline catalase with iron (II) salt is quiet effective andcapable of substituting sodium hydrosulphite with comparable dye strength and colour fastness. While reduction potentialvalues of dyebaths are found to be almost same in both hydrosulphite and alkaline catalase along with iron(II) salt systems,the stability of the baths in absence and presence of dye is found superior in the new reduction system as compared to thosein hydrosulphite system. Dye strength results show mixed findings, i.e. for some dyes, dye strength is higher in newreduction system, while for rest of the dyes, it is higher in hydrosulphite system

A Kinetic Analysis of Bleaching Synthetic Indigo in Solution

Indigo\u27s ability to dye a wide variety of fabric types gives it a prominent place in the textile industry. As a vat dye, indigo must be reduced to leuco-indigo to dissolve in water and dye fabric. It is common practice in the textile industry to bleach indigo-dyed denim to alter the final appearance of the garment. This research aims to determine the kinetic order of this bleaching process, using hydrogen peroxide as a bleaching agent for synthetic indigo. Vat solutions of synthetic indigo were made using fructose as the reducing agent and sodium hydroxide to create a reducing environment. Four indigo solutions of varying concentration were prepared from a synthetic stock solution. UV-Vis spectroscopy was used to measure the absorbance values (λ = 610 nm) of each indigo solution to generate a calibration curve. Hydrogen peroxide solutions of varying concentrations (4.0 x 10-3 M ± 1.0 x 10-4 M and 7.0 x 10-3 M ± 1.0 x 10-4 M) were related with a synthetic indigo solution. Changes in absorbance were monitored over time, for systems in which hydrogen peroxide was the limiting reactant and in excess. Graphical analysis determined hydrogen peroxide cannot adequately oxidize indigo on its own

Biobleaching of Industrial Important Dyes with Peroxidase Partially Purified from Garlic

An acidic peroxidase was extracted from garlic (Allium sativum) and was partially purified threefold by ammonium sulphate precipitation, dialysis, and gel filtration chromatography using sephadex G-200. The specific activity of the enzyme increased from 4.89 U/mg after ammonium sulphate precipitation to 25.26 U/mg after gel filtration chromatography. The optimum temperature and pH of the enzyme were 50°C and 5.0, respectively. The Km and Vmax for H2O2 and o-dianisidine were 0.026 mM and 0.8 U/min, and 25 mM and 0.75 U/min, respectively. Peroxidase from garlic was effective in decolourizing Vat Yellow 2, Vat Orange 11, and Vat Black 27 better than Vat Green 9 dye. For all the parameters monitored, the decolourization was more effective at a pH range, temperature, H2O2 concentration, and enzyme concentration of 4.5–5.0, 50°C, 0.6 mM, and 0.20 U/mL, respectively. The observed properties of the enzyme together with its low cost of extraction (from local sources) show the potential of this enzyme for practical application in industrial wastewater treatment especially with hydrogen peroxide. These Vat dyes also exhibited potentials of acting as peroxidase inhibitors at alkaline pH range

Dyeing of cotton with vat dyes using alkaline catalase alongwith iron(II) salt

109-115In this study, attempts have been made to replace sodium hydrosulphite with alkaline catalase in combination with iron (II) salt for dyeing cotton with vat dyes. The results show that alkaline catalase with iron (II) salt is quiet effective and capable of substituting sodium hydrosulphite with comparable dye strength and colour fastness. While reduction potential values of dyebaths are found to be almost same in both hydrosulphite and alkaline catalase along with iron(II) salt systems, the stability of the baths in absence and presence of dye is found superior in the new reduction system as compared to those in hydrosulphite system. Dye strength results show mixed findings, i.e. for some dyes, dye strength is higher in new reduction system, while for rest of the dyes, it is higher in hydrosulphite system

Decolorization of Anthraquinone Vat Blue 4 by the Free Cells of an Autochthonous Bacterium, Bacillus Subtilis

Uncontaminated soil, Vat Blue 4 contaminated soil and Vat Blue 4 effluent were screened for heterotrophic bacterial population and the bacterial density were found to be 19.3 £ 104 Colony Forming Units (CFU)/gm, 5.5 £ 104 CFU/gm and 1.1 £ 104 CFU/ml respectively. Student’s ‘t’ test analysis affirmed that significant variation prevailed between the three set of ‘t’ tests conducted (P , 0.001 to 0.002). The heterotrophic bacterial population of dye contaminated soil comprised of 32.5% of Pseudomonas spp. followed by 27.5% of Bacillus spp., 15.0% of Aeromonas spp., 12.5% of Micrococcus spp. and 12.5% of Achromobacter spp. The optimum inoculums load, pH and temperature were found to be 5% (10 £ 104 counts), 10 and 358C respectively. Free cells of B. subtilis decolorized Vat Blue 4 up to 92.30% after 24 hours of treatment. Total Dissolved Solids (TDS), Biological Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) were reduced up to 50.00, 79.60 and 75.40% respectively