Research Highlight: Marine Microbes Could Help Clean Up Environmental Pollutants

Marine bacteria first discovered off the coast of Puerto Rico more than 50 years ago could one day help clean up toxic pollutants in the environment.

Scripps Institution of Oceanography at the University of California San Diego researchers uncovered a new enzyme in marine bacteria that evolved to remove bromine from carbon. Bromine is one of four highly reactive members of the elemental group known as halogens that are also commonly found in man-made industrial chemicals such as pesticides and flame retardants.

Enzymes that remove halogens from man-made industrial compounds can be used to rid the environment of these harmful pollutants.

“In a strange twist of fate, a strategy used by a marine bacterium to make a molecule could actually help us break a molecule,” said Scripps researcher Abrahim El Gamal, a Scripps alumnus and lead author of the study. “This discovery could inspire new technology that might be utilized in bioremediation.”

Professor Bradley Moore and El Gamal from the Scripps Center for Oceans and Human Health identified the enzyme while analyzing the genes involved in the synthesis of pentabromopseudilin, an unusual natural chemical consisting of more than 70 percent of bromine.

The discovery of the bromine-removing enzyme completed the characterization of the biosynthesis of pentabromopseudilin 50 years after its historic discovery as the first marine bacterial antibiotic.

The pesticide methyl bromide, the flame retardant PBDE used in upholstery and plastics, and DDT are part of a group of halogenated chemicals that were commonly used in industrial and agricultural applications. These chemicals, called persistent organic pollutants, or POPs, are found in the environment and can make their way up the food chain into humans since they do not easily degrade.

Current techniques to remove these highly toxic pollutants from the environment require an energy-intensive process to remove a halogen to allow the chemicals to naturally degrade. The new study by the Scripps research team published in the Journal of the American Chemical Society could help identify a less energy-intensive process using the enzyme naturally produced by the marine microbe that would allow the pollutants to degrade more quickly in the environment.

“Understanding how the microbe assembles and disassembles its own natural halogenated chemicals will allow us to engineer the enzyme to work on industrial chemicals,” said Moore, a researcher in the Scripps Center for Marine Biotechnology and Biomedicine, UC San Diego Skaggs School of Pharmacy and Pharmaceutical Sciences and senior author on the study.

The next step for researchers in Moore’s lab is to use this information to develop new technologies based on the marine microbe to help mitigate these environmental pollutants.

The National Science Foundation’s Oceans and Human Health Program and the National Institute of Environmental Health Sciences funded the study.

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