Stimulation of microalgae growth and high-value compounds production by magnetic field exposure

Abstract

This study evaluated the effect of magnetic field (MF) intensities of 30, 60, and 120 militeslas (mT) applied for daily exposure times of 1, 2, or 4 h on the growth, CO2 uptake, and pigment production of Chlorella vulgaris, Coelastrella sp., and Arthrospira platensis. The results support the emerging consensus that MF intensities between 30–60 mT generally enhance biological activity, while 120 mT may induce stress and inhibit growth. Specifically, 60 mT significantly enhanced CO2 uptake and O2 production in C. vulgaris and Coelastrella sp., suggesting an intensification of photosynthetic activity. In contrast, 120 mT inhibited growth and CO2 uptake, particularly in A. platensis and Coelastrella sp. However, for C. vulgaris, exposure to 120 mT for 1 h per day produced contrasting effects, with a reduction in biomass productivity and growth, but a 26 % increase in chlorophyll content. At lower intensities, pigment production was also selectively enhanced, with carotenoids in Coelastrella sp. increasing by 51 % at 30 mT for 2 h per day, and phycocyanin in A. platensis rising by 53 % at 30 mT for 4 h per day. These findings indicated the presence of a magnetic “window” where specific field conditions optimized physiological responses in microalgae, supporting the potential use of MF in CO2 capture technologies coupled with the production of high-value biomolecules.