Production of Prodigiosin Using Serratia Marcescens from Tilapia Scale Hydrolysates: Influence of Stirring Speed and Nacl Concentration

Abstract

Prodigiosin is a bacterial pigment with therapeutic and antimicrobial properties. Although traditionally produced by Serratia marcescens, alternative methods based on agroindustrial waste are being explored. This research focused on determining the feasibility of obtaining prodigiosin using hydrolysates of Tilapia scales by Serratia marcescens QSC23, isolated from the La Libertad region in Peru. Wastewater from a treatment plant was collected and enriched in a Luria-Bertani medium to isolate colonies of the Serratia genus. These colonies were characterized morphologically, biochemically, and using molecular techniques, including 16S rDNA gene sequencing. Tilapia scales were obtained and subjected to alkaline hydrolysis to produce hydrolysates, which served as a culture medium for prodigiosin production. Different conditions of stirring speed (100 - 250 rpm) and NaCl (0.5 - 2.5%) were evaluated for prodigiosin production over a 72 h incubation period at an initial pH of 7 and 25 °C. QSC23 was able to produce prodigiosin, with a maximum production of 516.03 ± 15.84 units per cell under conditions of 150 rpm and 1.5 % NaCl from the fermentation of tilapia scale hydrolysates. The chemical characterization of the pigment was confirmed using UV-VIS spectroscopy methods. Serratia marcescens QSC23 demonstrated the ability to produce prodigiosin using fermentation residues from tilapia scales. This sustainable and cost-effective production offers a promising avenue for the global market of natural pigments.