An in-situ approach based in mineral oil to decrease end-product inhibition in prodigiosin production by Serratia marcescens

Abstract

Prodigiosin is an intense red microbial pigment produced by Serratia marcescens strains. Although various in-vitro activities make it attractive for the pharmaceutical and food industry, the production of this alkaloid is dramatically affected by media components and feedback inhibition, resulting in low productivities and high commercial costs. The present work proposes an interest low-cost production coupled to a two-phase in-situ product recovery system based on mineral oil to improve prodigiosin production. The scale-up of this strategy at batch and continuous processes was also studied. A medium composed of peanut (40 g/L) and defatted soybean flour (5.25 g/L) resulted in the highest prodigiosin titers. The addition of mineral oil (5 % v/v) triggered a 1.12-fold and 2-fold at pigment content and cell density, respectively. Scale-up at batch bioreactor resulted in a prodigiosin concentration of 1282 mg/L. However, continuous fermentation reached a 1.5-fold in the production rate compared to batch. Mathematical modeling was used to describe batch process behavior, obtaining all R2 above 0.975. From these results, a potential large-scale strategy could be proposed for an industrially attractive prodigiosin production system using S. marcescens via fermentation, alleviating end-product inhibition phenomenon and putting it in perspective with an economical approach.