Optimization of Bioreactor Cultivation Parameters by Taguchi Orthogonal Array Design for Enhanced Prodigiosin Production

One of the major steps toward the industrialization of the microbial product(s) is to optimize the cultivation conditions at the large-scale bioreactor and successfully control the microbial behavior within a large scale production environment. Statistical Design of Experiment was proven to optimize a vast number of microbial processes to achieve robustness and explore possible interactions among the variables. In this research, Taguchi Orthogonal Array was applied to optimize the cultivation condition of a newly isolated Prodigiosin-producing marine bacterial strain, Serratia AM8887, at the bioreactor level. The two-steps fermentation process was applied; as the productivity was scaled up from shake flask level to a benchtop bioreactor (5L) and subsequently to an in-situ sterilization bioreactor system (20L); yielding a 7g/L of the pigment; compared to 100mg/L before optimization confirming that; applying Taguchi experimental design is a reliable and good positive option for the optimization of biotechnological processes. The produced pigment was purified and the chemical structure was revealed using Spectrophotometric, Mass Spectrum (MS), Fourier Transform InfraRed (FT-IR), and proton Nuclear Magnetic Resonance (1H-NMR) spectroscopy analysis. The biological activity including antibacterial (against multidrug resistance), antioxidants (against 1,1-diphenyl-2-picrilhydrazyl) and cytotoxicity to cancer cell lines (against breast cancer MCF-7 and liver cancer HepG-2) of the pigment were explored showing very characteristic features that could be helpful in food, pharmaceuticals, and/or textile industries