Optimization of Fermentation Parameters and Medium Composition for Producing Prodiginines from Marine Bacterium Spartinivicinus ruber MCCC 1K03745T

Cycloheptylprodigiosin exhibits potent anticancer activity through a unique mechanism involving the induction of severe Golgi stress, a previously unrecognized cell death pathway. To increase the prodiginine production from the marine bacterium Spartinivicinus ruber MCCC 1K03745T, we investigated key fermentation parameters, including incubation time and initial medium pH. The culture medium composition was then sequentially optimized by single-factor experiments, a full factorial design, and an orthogonal design. Our results showed that the optimal incubation time was 30 h post inoculation, while initial pH had no effect on prodiginine production within the range of pH 6.0 to 8.0. By orthogonal design, the optimal medium was determined as follows: peptone 11 g/L, yeast extract 1 g/L, soybean oil 5 mL/L and MgCl2·6H2O 3 g/L in seawater. Verification experiments showed that prodiginine concentration under the optimized conditions reached 14.64 mg/L, representing 2.62 times the concentration obtained in basal Marine Broth 2216. These findings provide a basis for the cost-effective production of prodiginines from S. ruber MCCC 1K03745T for potential pharmaceutical applications.