Marine biologists from University of California – San Diego are investigating a common marine sponge which hosts bacteria with special properties. The organisms produce toxic compounds very close in composition to human-made fire retardants. While the chemicals may one day have industrial value, the immediate concern is with any risk to human health posed by the chemicals.
The chemical compounds are described as polybrominated diphenyl ethers (PBDEs) and there is evidence that these chemical leach out into the marine environment. As a chemical family PBDEs a type of brominated flame retardants. In industrial applications, the chemicals are added to foam, textiles, and electronics. Here they succeed in raising the temperature at which the products to which the combined mixture is added will burn at.
In the environment the chemicals can pose a risk to human- and animals health. The chemicals function as potent endocrine disruptors, and they create a reaction that is similar to the activity of the human body’s most active thyroid hormone.
The chemicals produced by bacteria on sponges was shown through the use of two advanced methods called genome “mining” and DNA sequencing (metagenomics). This allowed specific genes and enzymes, responsible for the toxic chemical production, to be identified.
The investigation into the chemicals has been undertaken by Dr. Vinayak Agarwal. In a research note the academic explains: “For the first time we were able to conclusively show that genes and enzymes produced in bacteria from sponges are responsible for the production of these compounds toxic to humans.”
In the marine environment, sponges filter seawater through the pores in order to get food. The process results in the animals hosting many bacteria, many of which have yet to be characterized. The identification of the toxin producing bacteria came from a research expeditions in the waters of Guam.
Further study will be required due to the risk of PBDEs ending up in the food chain. The research will determine how many different types of microorganisms produce these chemicals. The sponge and bacteria are described in the journal Nature Chemical Biology, with the research paper headed “Metagenomic discovery of polybrominated diphenyl ether biosynthesis by marine sponges.”
