Growth optimization of Klebsiella pneumoniae in magnetically assisted bioreactor

Abstract

In recent years, infections are more often caused by pathogens with high multi-drug resistance, classified as the “ESKAPE” microorganisms. Therefore, investigation of these pathogens, e.g., Klebsiella pneumoniae, often requires biomass production for treatment testing such as antibiotics or bacteriophages. Moreover, K. pneumoniae can be successfully applied as a biocatalyst for other industrial applications, increasing the need for this bacteria biomass. In the current study, we proposed a novel magnetically assisted bioreactor for the cultivation of K. pneumoniae cells in the presence of an external alternating magnetic field (AMF). High efficiency of the production requires optimal bacteria growth conditions, e.g., temperature and field frequency. Therefore, we performed an optimization procedure using a central composite design for these two parameters in a wide range. As an objective function, we utilized a novel, previously described growth factor that considers both biomass and bacteria growth kinetics. Thus, based on the response surface, we could specify the optimal growth conditions. Moreover, we analysed the impact of the AMF on bacteria proliferation, which indicated positive field frequency windows, where the highest stimulatory effect of AMF on bacteria proliferation occurred. Obtained results proved that the magnetically assisted bioreactor could be successfully employed for K. pneumoniae cultivation.