A "surfactant," technically, is a type of wetting agent that lowers surface tension between liquids but we recognize surfactants more commonly in such products as dishwashing detergent or shampoo. Biosurfactants are produced by living cells such as bacteria, fungi and yeast, and are generally non-toxic, environmentally benign and biodegradable. By comparison, chemical surfactants, which are usually derived from petroleum, are commonly toxic to health and ecosystems, and resist complete degradation.
Biosurfactants of various types are already used in a wide range of applications, from food processing to productions of paints, cosmetics, household products and pharmaceuticals. But they also have uses in decontamination of water and soils, with abilities to degrade such toxic compounds as heavy metals, carcinogenic pesticides and hydrocarbons.
Although the type of biosurfactant called "rhamnolipids" have been used for many years, the newly discovered strain, NY3, stands out for some important reasons. Researchers said in the new study that it has an "extraordinary capacity" to produce rhamnolipids that could help break down oil, and then degrade some of its most serious toxic compounds, the PAHs.
Rhamnolipids are not toxic to microbial flora, human beings and animals, and they are completely biodegradable. These are compelling advantages over their synthetic chemical counterparts made from petroleum. Even at a very low concentration, rhamnolipids could remarkably increase the mobility, solubility and bioavailability of PAHs, and strain NY3 of P. aeruginosa has a strong capability of then degrading and decontaminating the PAHs.
"The real bottleneck to replacing synthetic chemicals with biosurfactants like rhamnolipid is the high cost of production," Yin said. "Most of the strains of P. aeruginosa now being used have a low yield of rhamnolipid. But strain NY3 has been optimized to produce a very
|Contact: Xihou Yin|
Oregon State University