Isolation, Identification and Optimization of Natural Colorant Producing Soil-borne Aspergillus niger and Analysis of the Extracted Pigment

Abstract

Natural colorants have been used in various applications throughout human history, including food, dyes, pharmaceuticals, cosmetics, and various other products. The objective of this study was to separate the naturally occurring filamentous fungus Aspergillus niger from the soil and get pigments for prospective industrial uses. Five different soil samples were taken on the campus (botanical garden, polyhouse, agricultural farm) of Padmashri Vikhe Patil College, Pravaranagar, India. By using standard techniques, the Aspergillus niger was isolated and identified from the soil samples (morphological & microscopic characteristics). To produce pigment, Aspergillus niger was cultured in five different liquid media for 7 days under shaking conditions: potato dextrose broth (PDB), Czapek-Dox broth (CDB), yeast extract malt extract broth (YMB), Sabouraud dextrose broth (SDB), and nutrient broth (NB). The pigments were extracted from the biomass using an ethanol-based extraction technique, and the biomass was then concentrated using a rotary evaporator. Five samples allowed for the isolation of Aspergillus niger, and a yield estimate for the brown pigment that was recovered from Aspergillus niger was made. Utilizing a UV-VIS spectrophotometer, secondary metabolites testing, and spectroscopic analysis of the pigments, it was determined whether they had antibacterial efficacy against test organisms. The composition of the medium had an impact on the pigment. In this study, this species produces more pigment after eight days of culture under various circumstances, including 25°C and pH 4. Carbon and nitrogen are the sources that are necessary for the creation of secondary metabolites and biomass. Temperature, pH, carbon supply, aeration, and fermentation type all affect the pigments because they are by-products of fermentation (solid or submerged). As low-cost, fungi can be used as color production cell factories. The food, pharmaceutical, bio-paint, and textile industries all have emerging uses for fungal pigments.