Optimization of prodigiosin production from a strain of Serratia marcescens SR₁ and screening for antifungal activity

Prodigiosin produced by Serratia marcescens strain (SR₁) is a promising drug owing to its reported characteristics of having antifungal, immunosuppressive and antiproliferative activity. From a commercial point of view, there is a necessity to select a suitable medium for the enhancement of cell growth as well as pigment production simultaneously, from Serratia marcescens (SR₁) was the aim of the work. Compared to the nutrient broth and glycerol-yeast extract media, the casein-enriched medium supplemented with 4% vegetative oil mixture (sunflower, coconut and olive oil) showed a higher yield of prodigiosin (765.1 mg I⁻¹) with a cell weight (2.1 g I⁻¹ dry wt), was observed after the incubation period of 84 h at 30 ± 2°C with pH 7.0. The antifungal activity of the crude prodigiosin, separated through solvent extraction process and purified by TLC was tested against fungal pathogens following the well-diffusion method, which showed the maximum inhibitory zone against Helminthosporium sativum, Fusarium oxysporium and Rhizoctonia solani in decreasing order.