Evaluation of ferrofluid-coated rotating magnetic field-assisted bioreactor for biomass production

Abstract

• Synthesised Fe 3 O 4 particles expressed superparamagnetic properties. • Ferrofluidic coat strengthened electromagnetic field in bioreactors. • The ferrofluidic coat had an opposing influence on the growth rate of model bacteria. • Higher values of magnetic induction stimulated S. aureus biomass production. The primary purpose of this study is to develop a novel type of magnetically assisted reactor for the production of bacterial biomass. Following this aim, we applied a ferrofluidic or water coat around the culture tubes that modified the generated rotating magnetic field (RMF) characteristics. Fe 3 O 4 nanoparticles have been described, and their modulating effect on RMF was tested. Upgraded reactors were used to produce biomass of model microorganisms, i.e., E. coli and S. aureus . Approximations based on the Gompertz model indicated a simulative effect (approximately 30% and 5%) on bacteria growth rate with the application of water and ferrofluid coat, respectively, depending on the microorganism. More profound differences were detected in the cell viability (between 5 and 45%) and the levels of reactive oxygen species (between 5 and 190%). The results suggest that the proposed method of biomass production with the application of ferrofluidic coats in the magnetically assisted reactor can affect the growth rate and the levels of reactive oxygen species in cultured bacteria, depending on the microorganisms and the used coating. Our findings show that either ferrofluidic or water coating can be used explicitly in biomass production to best suit the production goals.