Isolation and Identification of Natural Colorant Producing Soil-Borne Aspergillus niger from Bangladesh and Extraction of the Pigment

Abstract

Natural colorants have been used in several ways throughout human history, such as in food, dyes, pharmaceuticals, cosmetics, and many other products. The study aimed to isolate the natural colorant-producing filamentous fungi Aspergillus niger from soil and extract pigments for its potential use specially for food production. Fourteen soil samples were collected from Madhupur National Park at Madhupur Upazila in the Mymensingh district, Bangladesh. The Aspergillus niger was isolated and identified from the soil samples by following conventional mycological methods (cultural and morphological characteristics), followed by confirmatory identification by a polymerase chain reaction (PCR) of conserved sequences of ITS1 ribosomal DNA using specific oligonucleotide primers. This was followed by genus- and species-specific primers targeting Aspergillus niger with an amplicon size of 521 and 310 bp, respectively. For pigment production, a mass culture of Aspergillus niger was conducted in Sabouraud dextrose broth in shaking conditions for seven days. The biomass was subjected to extraction of the pigments following an ethanol-based extraction method and concentrated using a rotary evaporator. Aspergillus niger could be isolated from three samples. The yield of extracted brown pigment from Aspergillus niger was 0.75% (w/v). Spectroscopic analysis of the pigments was carried out using a UV–VIS spectrophotometer. An in vivo experiment was conducted with mice to assess the toxicity of the pigments. From the colorimetric and sensory evaluations, pigment-supplemented products (cookies and lemon juice) were found to be more acceptable than the control products. This could be the first attempt to use Aspergillus niger extracted pigment from soil samples in food products in Bangladesh, but for successful food production, the food colorants must be approved by a responsible authority, e.g., the FDA or the BSTI. Moreover, fungal pigments could be used in the emerging fields of the food and textile industries in Bangladesh.

Molecular detection of Aspergilli from commercial chicken in selected areas of Bangladesh

“…In this study, molecular detection of Aspergillus spp. was carried out by PCR using genus-specific primers ASAP-1 and ASAP-2 that amplified a fragment of 521 bp in length [ 18 , 19 ]. Specific Aspergillus species were identified using species-specific primers (FLA-1 and FLA-2 for A. flavus , ASPU and Af3r for A. fumigatus, and ASPU and Nilr for A. niger ) [ 19 – 21 ].…”

Isolation and characterization of pigment producing fungi

“…After 7 days of incubation, a significant amount of pigment was obtained in the flasks, since the pigments produced by the fungal isolates are water soluble; they were directly obtained in the broth. The fungal biomass was filtered using normal filter paper and the supernatant was collected and preserved in dark brown vials for characterization of fungal pigments [24][25][26][27].…”

The Potentials of Isolated Hexadecanoic Acid of Hydroid Aglaophenia cupressina Lamoureoux as an Antifungal Compound on the Rotten Strawberries Fragaria x ananassa Dutch. and Mango Mangifera indica L

“…moreover, the spores had an asexual reproduction in the form of conidiospore. the observed isolates were under the microscopic characteristics of the fungus aspergillus niger [31]. he deploys that the fungus aspergillus niger has smooth upright conidiospore shaping globus [32].…”