Examining the Growth of Methanotrophic Bacteria Immersed in Extremely Low-Frequency Electromagnetic Fields

Abstract

The demand for natural resources, and consequently greenhouse gas (GHG) emissions, are only set to increase in the next several decades. Methane gas, having 80 times more warming power than carbon dioxide over a 20 year period, accounts for about 10% of all U.S. GHG emissions primarily due to the agriculture and waste management industry. GHGs trap heat in Earth’s atmosphere causing rising surface temperatures and sea levels, ocean acidification, and extreme weather patterns. Methylomicrobium alcaliphilum 20ZR is a methanotrophic bacterium currently being explored as a means for mitigating these emissions and/or production of value-added compounds from wasted sources of methane. Based on related studies, we predicted that exposure to low-frequency electromagnetic fields for 5 and 15 minutes would be a feasible method to increase the growth rates of M. alcaliphilum 20ZR, while 30 minutes would decrease the growth rates. We hypothesized that this increase in growth could make this method of catabolizing methane more practical given the slow growing nature of methanotrophs in standard conditions. However, our data showed that exposure to an electromagnetic field density of 0.1 milliTesla (mT) at a frequency of 50 hertz (Hz) for 5, 15, and 30 minutes had no statistically significant effects on the growth of M. alcaliphilum 20ZR when compared to the control. The results of this study therefore do not fully support our hypothesis that an electromagnetic field can positively impact microbial growth, but future research should be done to further solidify and expand upon the data collected.