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ABSTRACT
Methyl tert-butyl ether (MTBE), which has been widely used as a fuel oxidant, is a toxic gas that causes serious air pollution and even cancer. Furthermore, metabolites of MTBE, tert-butyl alcohol (TBA) and formaldehyde (HF) are toxic agents. In this study, the effects of MTBE, TBA and HF on the specific growth rates of 3 microorganisms (Escherichia coli, Bacillus amyloliquefaciens, and Pseudomonas aeruginosa) were qualitatively and quantitatively examined to estimate the toxicity of these materials and the microbes under the conditions of single, dual and triple mixtures of the chemicals. While the growth of gram negative bacteria (E. coli and P. aeruginosa) was completely inhibited at 20 g/L of MTBE, that of gram positive bacteria (B. amyloliquefaciens) was thoroughly inhibited at 60 g/L. As well as MTBE, B. amyloliquefaciens showed higher tolerance to TBA and HF than both E. coli and P. aeruginosa. In dual mixtures (TBA + MTBE), E. coli and P. aeruginosa revealed similar tolerance like single test. Otherwise, E. coli had more sensitivity in dual mixtures (MTBE + HF) and P. aeruginosa did more in MTBE plus TBA. B. amyloliquefaciens was wholly inhibited in the concentration of MTBE 30 g/L plus TBA 20 g/L.
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