Biosynthesis of bioactive pigment from halotolerant Bacillus cereus for fabric – an eco-friendly initiative

Synthetically produced pigments have great demand in various industries; however, the toxic effects of synthetic pigments make their use in industries burdensome. This has led to the production of alternate eco-friendly methods. Pigments produced from microbes play a significant role as safe pigments are needed for sensitive industries like food, dyeing, and the textile industry. Potential bacterial pigments have attracted attention as they have better prospects, are eco-friendly, and are non-toxic. The current work was aimed at the isolation and characterization of pigment-producing halotolerant bacterial strains from saline environments. Their growth parameters such as pH, temperature, NaCl concentrations, and carbon and nitrogen sources for effective pigment production were optimized. The extracted bio-pigment was purified and characterized by FTIR, GC-MS, and HPLC analysis. GC-MS data of the pigment revealed three possible structures – 5-oxo-N-phenyl-3-(o-toluidinyl) 3-pyrrolidine Carboxamide (A), dibenzoate ester of phenyl 1,4-dihydroxylamine (B), and 9-acetyl phenanthrene (C). FTIR spectrum of the pigment showed characteristic bands for nitrogen, indicating the pigment structure to be either (A) or (B). Furthermore, the extracted pigment was applied to cotton fabric as a dye to study its effect. The pigment was found to bind well with cotton fabric at 40 °C in the presence of thiourea. The wash performance of the pigment was also found to be superior in the presence of thiourea. The halotolerant bacterial strain was identified by 16s RNA sequencing as Bacillus cereus. Hence, the pigment produced by Bacillus cereus indicates that the pigment has an affinity to cellulose that could possibly be used for textile coloring in a range of clothing in various materials.