Solid-state fermentation of food waste by Serratia marcescens NCHU05 for prodigiosin production

Abstract

BackgroundProdigiosin is a red colored pigment with applications in antibacterial, antifungal, anticancer, and immunosuppressive activities. It is produced as a secondary metabolite by bacteria genera such as Serratia, Pseudomonas, and Streptomyces. The high-value prodigiosin offers a promising opportunity for the valorization of local food wastes. MethodsThe newly found red pigment-producing colony was isolated, sequenced, and identified. The red pigment was characterized using UV–VIS and liquid chromatography mass spectrum. Two cultivation methods, submerged culture and solid-state fermentation (SSF), were employed to produce prodigiosin. Three food waste sources, including rice bran, fish meal, and soybean dreg, were employed as both nutrition and solid matrices for SSF. Significant findingsA new red pigment-producing Serratia marcescens NCHU05 was successfully isolated and identified. The red pigment was characterized as prodigiosin. S. marcescens NCHU05 was employed for prodigiosin production. SSF outperformed submerged cultures in prodigiosin production. Specifically, SSF using LB1 agar plate (1 g/L NaCl) yielded 22 mg/kg-dry-solid, while submerged cultures in LB1 medium produced only 3.2 ± 0.2 mg/L. Remarkably, when rice bran, fish meal, and soybean dregs were used as nutrients and solid matrices for SSF, prodigiosin productions of 50, 54, and 79 mg/kg-dry-solid were achieved, respectively. This study illustrates the feasibility of utilizing locally isolated microorganisms to contribute to the valorization of local wastes.