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In the present study, cotton fabric has been dyed with aqueous extract of babul bark (Acacia nilotica) using gallnut (Quercus infectoria) as bio-mordant containing hydrolyzable tannins like gallic acid, elagic acid and polyphenolic gallotannins to produce light yellow color. On the other hand when gallnut bio-mordanted cotton is subsequently dyed with babul bark extract as a natural dye containing similar but non-hydrolyzable tannin-rich color component including small amount of catechin and epi-gallo-catechin, it produces a medium to deep brown color through formation of giant insoluble colored complex of cotton-gallotannins (gallnut)-catechin/epigallocatechin and other color components present in babul bark extract. The process variables for extraction, pre-mordanting and dyeing have been optimized to standardize this dyeing technique. Scattered CDI values for dye-bath pH and dye concentration identified them as the most important dyeing parameters that need to be controlled for obtaining uniform dyeing. High UPF value of upto 35 rendered by application of both gallnut and babul bark through preferential absorption of UV light by the gallotannins in both gallnut and babul bark indicates good UV protection properties of dyed cotton fabrics.

In the present study, cotton fabric has been dyed with aqueous extract of babul bark (Acacia nilotica) using gallnut (Quercus infectoria) as bio-mordant containing hydrolyzable tannins like gallic acid, elagic acid and polyphenolic gallotannins to produce light yellow color. On the other hand when gallnut bio-mordanted cotton is subsequently dyed with babul bark extract as a natural dye containing similar but non-hydrolyzable tannin-rich color component including small amount of catechin and epi-gallo-catechin, it produces a medium to deep brown color through formation of giant insoluble colored complex of cotton-gallotannins (gallnut)-catechin/epigallocatechin and other color components present in babul bark extract. The process variables for extraction, pre-mordanting and dyeing have been optimized to standardize this dyeing technique. Scattered CDI values for dye-bath pH and dye concentration identified them as the most important dyeing parameters that need to be controlled for obtaining uniform dyeing. High UPF value of upto 35 rendered by application of both gallnut and babul bark through preferential absorption of UV light by the gallotannins in both gallnut and babul bark indicates good UV protection properties of dyed cotton fabrics. [ABSTRACT FROM AUTHOR]

In the present study two unconventional fibres i.e banana and lotus having important functional properties have been dyed with aqueous extract of babul bark in soothing shades of brown. Among the two fibres, banana fibre gave best results in terms of dye uptake and fastness properties. In general use of mordant (aluminium sulphate) does not affect the overall dyeability and fastness of the dyeing in most cases. [ABSTRACT FROM AUTHOR]

Abstract A potential tannase producing fungus S3-07 was isolated from the tannin-rich soil sample and screened as better tannase producer with 38 ± 3 mm diameter of hydrolysis zone formation. It was identified as T. verruculosus (accession number KX863699) on the basis of the internal transcribed spacer ribosomal DNA (ITS-rDNA) sequence analysis. Tannase was produced with 8.22 ± 0.35 Unit per gram dry substrate (U/gds) activity in the unoptimized condition through solid state fermentation (SSF) using Babul (Acacia nilotica) bark as a solid substrate. Central composite design (CCD) was used to maximize the production and achieved 3.91 fold increments (32.18 ± 1.31 U/gds). Ammonium sulfate precipitation with 70% saturation and DEAE fractionation obtained 13.289 specific activity, 47.489% yield and 6.896 purification fold. SDS-PAGE and zymographic analysis showed two bands of tannase with ∼75 kDa and 58 kDa pH optima of tannase was measured at 8.00, whereas pH stability was recorded between 4.0 and 8.0. Tannase had temperature optima at 60 °C, however, stability was observed between 30 and 60 °C. In presence of ethanol, SDS, Mn2+ ions and gallic acid increased tannase activity, whereas ethyl acetate, tween 20, Ba2+ ion and urea inhibited maximum activity. Most of tannin reduction (93.27%) was measured in case of orange juice after 15 min incubation and 89.36% reduction in pomegranate juice after 30 min, whereas aonla juice was measured with 75.49% tannin reduction after 45 min incubation. [ABSTRACT FROM AUTHOR]