Assessment of process parameters influencing the enhanced production of prodigiosin from Serratia marcescens and evaluation of its antimicrobial, antioxidant and dyeing potentials

Aims: Prodigiosin is a bright red pigment produced by certain strains of Serratia marcescens, characterized by a common pyrrolylpyrromethane skeleton. This pigment is found to possess antibacterial, antifungal, immunosuppressive and antiproliferative activity. The present study aimed at designing process parameters for the enhanced production of this pigment. Methodology and Results: Peptone glycerol broth was selected as the best synthetic medium. The effects of various media components and process parameters like carbon and nitrogen sources, temperature, pH, incubation period and other supplements were investigated. Maximal amount of prodigiosin was produced at temperature 25 °C, pH 7.0 and incubation period of 48 h. Supplementation of media with maltose and peptone yielded maximal amount of prodigiosin. Incorporation of minimal amount of supplements like silica gel, iron salts, inorganic phosphate also showed promising results. Chromatographic separations suggested that prodigiosin is made up of three different fractions (purple, orange and red). Further investigation of antimicrobial properties of prodigiosin revealed that it is a potent inhibitor against gram positive bacteria like Staphylococcus aureus and Bacillus cereus and fungal pathogens like Candida albicans, C. parapsilosis and Cryptococcus sp. This antimicrobial potency remained stable under a wide range of temperature and pH. The antioxidant capacity of prodigiosin was found to be 22.05 Bg ascorbic acid equivalents/ml of extract. When applied to textiles, prodigiosin resisted the action of acid, alkali and detergent. Conclusion, Significance and Impact of study: Besides combating gram positive bacterial pathogens and some pathogenic yeasts, prodigiosin with strong dyeing and antioxidant activity may find broad applications in textile and therapeutic industries.