Uses of Effective Microorganisms
Effective Microorganisms (EM) is a culture made from a combination of photosynthetic bacteria, lactic acid bacteria, yeasts, and actinomycetes (Higa & Parr, 1994), and is proposed to have agricultural, medicinal, and environmental uses . With the novelty of such technology, there has been a large amount of research to test the effectiveness of EM and its claimed uses. Findings show that while EM has no impact in areas such as water treatment, it is useful for crop farming and composting, and it may be effective in treating cancer, asthma, and neurodegeneration.
One claim made by its producers is that EM is very useful in farming because it can increase the yield and quality of crops when used as a supplement (Higa & Parr, 1994). A study by Hu and Qi (2013) put this claim to the test by adding EM to a mixture of compost, and measuring wheat grain yield and the growth of nematodes, which are important soil organisms involved in nutrient recycling and decomposition. Results showed that the number of nematodes, as well as crop biomass and yield were much greater in soil treated with EM compost than in soils treated with nitrogen-phosphorus (NP) fertilizers or traditional composts alone. Another study by Jusoh, Manaf, and Latiff (2013) attempted to further examine EM composts and their quality compared to traditional compost and found that EM composts had a higher concentration of nitrogen, potassium, calcium, and iron. Such minerals are used (in trace amounts in the case of iron) for the growth and metabolism of the plant (Robertson & Vitousek, 2009; Leigh & Wyn Jones, 1984; Kabata-Pendias & Kabata, 1992). These findings show that the use of EM composts results in richer soils that can improve the quality and yield of crops.
As EM composts give rise to better soil quality and crop yield, it is already clear that they can benefit the environment by acting as alternatives to inorganic fertilizers. However, other environmental uses of EM have not yielded positive results. A study by Szymanski and Patterson(2003) tested the ability of EM in cleaning septic tanks and concluded that it is not effective in removing any significant amount of suspended materials from it. EM has also shown to be in ineffective in treating cyanobacteria blooms in water, despite claims that the potentially useful bacteria in it would replace harmful bacteria (Lürling, Tolman & Oosterhout, 2010). More recent studies are attempting to assess the effectiveness of EM in treating heavy metal pollution in water, which can be toxic to the surrounding ecosystems, yet the findings are not promising. Tang et al. (2013) compared the abilities of alginate-immobilized EM and normal EM and found that while the former can be useful in removing heavy metals, the effects were largely because of the alginate gel itself, and not the EM.
To date, attempts at finding effective environmental uses for EM have been largely unsuccessful; however, as evident from its use as a good alternative to other fertilizers in farming practices, EM can have great environmental effects and further research is required to assess its true potential.
While the majority research is focused on the agricultural and environmental uses of EM, there has also been some research on its possible medicinal uses. EM-X1, a version of EM suited for human consumption, has shown to be effective in treating in vitro human cancer cell types such as KG1a acute myelogenous leukaemia (AML) and Hep3B hepatocellular carcinoma(HCC) by causing apoptosis in the affected cells (Chui, Hau et al. 2006). Another way in which EM can have anti-proliferation effects on cancer cells is by reducing the number of vascular endothelial growth factors (VEGF) in in vitro conditions, and it may also act against angiogenesis, a process that is required for tumour growth (Chui, Gambari et al. 2006). EM-X1, as shown by Aruoma et al. (2003), can also be used as a treatment for neurodegeneration because it is able to hinder oxidative stress processes. Another medicinal use of EM is in treating asthma by reducing the number of type 2 helper T cells (TH2), so that less Immunoglobulin E (IgE) is produced, resulting in a decrease in the airway hyperresponsiveness seen in asthmatics (Do et al. 2006). A number of medicinal uses for EM have been verified; however, more research is required until it is ready for practical use.
 Higa, T. & Parr J.F. 1994. “Beneficial and Effective Microorganisms for a Sustainable Agriculture and Environment.” International Nature Farming Research Center, Atami, Japan.
 Hu, C. and Qi, Y. 2013. “Effective microorganisms and compost favor nematodes in wheat crops.” Agronomy for Sustainable Development, 33(3): 573-579.
 Jusoh, M.L., Manaf, L.A., & Latiff, P.A. 2013. “Composting of rice straw with effective microorganisms (EM) and its influence on compost quality.” Iranian Journal of Environmental Health Science Engineering, 10(1): 17.
 Robertson, G.P., & Vitousek, P.M. 2009. “Nitrogen in agriculture: balancing the cost of an essential resource.” Annual Reviews of Environment and Resources, 34: 97-125.
 Leigh, R. A., Wyn Jones, R. G. 1984. "A Hypothesis Relating Critical Potassium Concentrations for Growth to the Distribution and Functions of This Ion in the Plant Cell.” New Phytologist, 97: 1–13.
 Kabata-Pendias, A., Kabata, F. 1992. Trace element in solid and plant. Florida: CRC Press.
 Szymanski, N. and R. A. Patterson. 2003. “Effective microorganisms (EM) and wastewater systems.” Future Directions for On-site System: Best Management Practice Proceedings of On-site '03 Conference. 348-355.
 Lürling, M., Tolman, Y., and Oosterhout, J. 2010. “Cyanobacteria blooms cannot be controlled by effective microorganisms (EM) from mud- or Bokashi-balls.” Hydrobiologia, 646 (1): 133-143.
 Ting, A. S. Y., Rahman N. H. A., Isa, M. I. H. M., Tan, W. S. 2013. “Investigating metal removal potential by Effective Microorganisms (EM) in alginate-immobilized and free-cell forms.” Bioresource Technology, 147: 636-639.
 Chui, C., Hau, D., Lau, F., Cheng, G., Wong, R., Gambari, R., Kok, S., Lai, K., Teo, I.,Leung, T., Higa, T., Ke, B., Tang, J., Fong, D., and Chan, A. 2006. “Apoptotic potential of the concentrated effective microorganism fermentation extract on human cancer cells.” International Journal of Molecular Medicine, 17(2): 279-284.
 Chui, C., Gambari, R., Lau, F., Hau, D., Wong, R., Cheng, G., Kok, S., Higa, T., Ke, B.,Chan, A., Fong, D., and Tang, J. 2006. “Antiangiogenic activity of a concentrated effective microorganism fermentation extract.” International Journal of MolecularMedicine, 18(5): 975-979.
 Aruoma, O., Moncaster, J.A, Walsh, D.T., Gentleman, S.M., Ke, B., Liang, Y., Higa, T.,and Jen, L.S. 2003. “The Antioxidant Cocktail, Effective Microorganism X (EM-X), Protects Retinal Neurons in Rats Against N -methyl- d -aspartate Excitotoxicity In Vivo.” Free Radical Research, 37(1): 91.
 Do, J., Choi, Y., Seo, H., Ryoo, J., and Nam, S. 2006. “Effective Microorgainsm (EM)Fermentation Extract Attenuates Airway Hyperreactivity and Lung Inflammation In A Mouse Model of Asthma.” Journal of Bacteriology and Virology, 36(1): 1-10.