An in situ extractive fermentation strategy for enhancing prodigiosin production from Serratia marcescens BWL1001 and its application to inhibiting the growth of Microcystis aeruginosa

Abstract

Prodigiosin is a promising microbial metabolite with multiple bioactivities. However, due to its high cost of production and extraction, the large-scale production and application of prodigiosin are hampered. In this study, a prodigiosin-producing strain was isolated and identified as Serratia marcescens BWL1001. Using soybean oil as the optimal carbon source (C) and peptone as optimal nitrogen source (N), with the C/N ratio of 100/10, cultivation temperature of 28 °C, initial medium pH of 5.0, the maximum yield of prodigiosin (27.65 g/L) in first batch was obtained. Soybean oil acts as the carbon source, providing precursors for prodigiosin biosynthesis and relieving feedback inhibition, as well as promotes prodigiosin biosynthesis by increasing the expression of prodigiosin biosynthetic genes at the transcriptional level. Furthermore, an in situ extractive continuous fermentation strategy was developed using soybean oil as the carbon source and extractant, which significantly increased the prodigiosin yield and decreased the consumption of traditional organic solvent, and the soybean oil could be recycled after extracting prodigiosin. In addition, prodigiosin produced by BWL1001 showed 91.1 % algicidal activity against Microcystis aeruginosa. Thus, this study promotes the production of prodigiosin and its application in inhibiting harmful alga M. aeruginosa.