Parametric Study of the Effect of Increased Magnetic Field Exposure on Microalgae Chlorella vulgaris Growth and Bioactive Compound Production

Abstract

This parametric study aimed to analyze the effects of increased magnetic field exposure (MFE) on the growth and production of the bioactive compounds of Chlorella (C.) vulgaris. With the intent of studying the effect of an increased MFE, the magnetic field typically experienced by life on Earth was amplified by an order of magnitude. In the increased-MFE environment, six treatments of C. vulgaris with two repetitions for each treatment were exposed to a magnetic field of 5 Gauss (500 µT) about each axis, which was generated in a state-of-the-art Helmholtz cage. The treatments and the control were characterized by the duration of exposure, which was varied from 0 min to 120 min with a step increment of 20 min. The treatments were repeated for six days (TR1) and twelve days (TR2) in two separate experiments. From the first day of the treatment, the specimens in both the experiments were propagated for twenty-one days. For parametric analysis, the overall growth, protein, and beta-carotene content were measured every three days for twenty-one days. For TR1 in general, the samples treated with the increased MFE demonstrated a higher growth rate than the control. Specifically, for the specimen treated with 40 min of the increased MFE, the growth on the 21st day was measured to be 38% higher than the control. For the specimen treated with 120 min of the increased MFE, the protein content on the 15th day was measured to be 15.6% higher than the control. For the specimen treated with 40 min of the increased MFE, the beta-carotene content on the 15th day was measured to be 20.4% higher than the control. For TR2 in general, the results were inferior compared to TR1 but showed higher production than the control specimen. Specifically, for the specimen treated with 80 min of the increased MFE, the protein content on the 21st day was measured to be 4.3% higher than the control. For the specimen treated with 100 min of the increased MFE, the beta-carotene content on the 15th day was measured to be 17.1% higher than the control. For the specimen treated with 100 min of the increased MFE, the growth on the 21st day was measured to be 5% higher than the control. Overall, the treated specimens in TR1 exhibited significantly higher production compared to the control specimen. The treated specimen in TR2 demonstrated some adverse impacts, but still exhibited higher production compared to the control specimen.