Extraction and characterization of pigment from Sclerotinia sp. and its use in dyeing cotton

Abstract

The fruiting body of a cup fungus was collected from a compost pit containing fresh cow dung amended with biodynamic herbal preparations. The fungus was identified as Sclerotinia sp. by following standard procedures. The mycelial growth of S clerotinia sp. on cow pat pit manure was monitored for 90 days and on day 5 pin head primordia were observed and matured into individual fruiting bodies (0.5 cm diameter each, 1 gram fresh weight) on day 20. The fruiting body started yielding dark green spores and the spore deposits were seen on the top surface of the fruiting body. The spores are liberated from the fruiting bodies when they receive an external stimulus. The Sclerotinia sp. spore was elliptical in shape and was 2 µm in size when examined under phase contrast microscope at 40x. The dark green spore of Sclerotinia sp. excretes a pinkish red pigment in distilled water (pH 6.5). Spectrophotometer scanning (200—800 nm) of the pigment showed three peaks: 507 nm (optical density (O.D.) 0.554), 525 nm (O.D. 0.629), and 545 nm (O.D. 0.567). The pigment had high protein content (0.332 mg/ml) but no deductible amount of carbohydrates or lipids. Stability of the pigment was tested at various temperatures (40—100°C) and no change in its original color was observed under UV—visible spectral scan analysis. Pigment from Sclerotinia sp. changed its original pinkish red color at various pH values (pH 2.0, 3.0, and 14.0). The antibacterial activity of this pigment extract was tested on seven different bacteria of which a zone of inhibition was observed for E. coli. The pigment from Sclerotinia sp. applied on cotton yarns pretreated with different mordants gave different color shades, which were confirmed using the standard color code index.