Superfund Research Program

August 2023

Hot Publication

Researchers at the OSU SRP Center uncovered the ability of Rhodococcus bacteria — microorganisms with bioremediative properties — to remove contaminants from drinking water under different environmental conditions.

Benzene, toluene, ethylbenzene, and xylenes (BTEX) and methyl tert-butyl ether (MTBE) are environmental pollutants, often found at the same contaminated sites, that are associated with cancer, neurotoxicity, and reproductive effects. BTEX can enter water sources through forest fires, combustion of petroleum products, and the manufacturing of solvents, paints, and rubbers. MTBE is a gasoline additive and, despite its replacement by ethanol in the U.S., is still used in gasoline in many countries.

Previous studies have shown that Rhodococcus bacteria are able to break down BTEX and MTBE. However, this is the first study to investigate how growth substrates — materials that provide nutrients to support microorganism growth — affect the bacteria's ability to degrade the chemicals, both individually and in mixtures.

The researchers grew the bacteria on three different alcohol-based substrates — isobutane, 1-butanol, and 2-butanol — and then exposed them to the contaminants. In separate experiments, the team exposed the bacteria to BTEX and MTBE while they were still growing to determine how early exposure impacted their remediation abilities.

They found that bacteria grown on isobutane had the greatest ability to break down BTEX and MTBE, alone and in mixtures, followed by 2-butanol and 1-butanol. However, in conditions where BTEX and MTBE were present during microbial growth, 1-butanol was the most effective substrate for enhancing bacterial growth and contaminant degradation.

According to the researchers, alcohol-based substrates are effective in supporting Rhodococcus bacteria’s bioremediation of BTEX and MTBE, indicating a potential approach to prevent environmental exposures to the contaminants.

To learn more, please refer to the following sources:

  • Huizenga JM, Semprini L. 2023. Influence of growth substrate and contaminant mixtures on the degradation of BTEX and MTBE by Rhodococcus rhodochrous ATCC strain 21198. Biodegradation doi:10.1007/s10532-023-10037-2 PMID:37329399