Discovery of naturally produced bioemulsifiers to remediate the next oil spill

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Crude oil accidents, either on land or in the ocean, have devastating environmental consequences, especially in pollution-sensitive habitats. Large amounts of oil from the Exxon-Valdez accident in 1989 in Alaska and the Deepwater Horizon accident in 2010 in the Gulf of Mexico washed up and were buried in shoreline sediments where they have persisted for decades. Microorganisms are the first to respond to environmental contamination and process most of the oil that enters the environment. However, oil biodegradation may be extremely slow and, as a result, oil ends up sinking and then is buried in sediments. Buried and harmful polycyclic aromatic hydrocarbons associated with oils can then be released to the surface during storm events causing further environmental damage. The common emergency response strategy to oil spills is to apply chemical dispersants to facilitate oil dispersion and dissolution. However, such chemicals can have high toxicity to microbes that degrade oil in the environment. Thus, new products are needed. The overarching objective of this project is to develop new, environmentally friendly dispersants, surfactants, and emulsifiers to remediate future oil spills. To achieve this objective, the research team will study the natural emulsifiers produced by coastal bacteria that were discovered in the aftermath of the Deepwater Horizon oil spill and then test effective crude-oil degraders. The successful completion of this project will benefit society through the identification of environmentally friendly and effective emulsifiers for crude-oil degradation. Additional benefits to society will be achieved through student education and training including the mentoring of two graduate students at Georgia Tech. Oil spills require millions of liters of chemical dispersants to help remediate damage. Environmentally benign and effective emulsifiers and surfactants are needed to address oil spills where the use of previous chemical dispersants have been banned. The research team has recently reported the metagenome-guided isolation of a novel bacterium, provisionally named Candidatus Macondimonas diazotrophica, that represents a phylogenetically narrow group of previously uncharacterized, crude-oil degraders. These microorganisms are highly abundant in oiled sediments of coastal marine ecosystems across the world, often comprising up to ~30% of the total microbial community, while being low abundance in adjacent, non-contaminated samples. This high abundance in a natural ecosystem suggests unusual physiological capabilities in these microorganisms that confer advantage over other microbes when exposed to oil contamination. The bioinformatic annotation of the Ca. M. diazotrophica genome has revealed several novel biosynthetic clusters that are predicted to produce lipid-based bioemulsifiers and surfactants. The overall goal of this project is to identify and characterize these new bioemulsifiers and test their ability to speed up crude oil biodegradation. The emerging bioremediation technologies will fill a gap in remediation techniques for oil spill-related disasters. These bioemulsifiers are also likely to find applications in enhanced oil recovery from natural habitats as well as in the detergent industry as a replacement for chlorinated solvents. Hence, the broader impacts of the resulting bioemulsifiers and technologies will affect multiple science and engineering disciplines and find several practical biotechnological applications. Students will be trained at the interface of cutting-edge metagenomics and bioinformatics with bioprospecting, chemistry, and engineering. The experience gained from the educational activities will be shared in a workshop with faculty from undergraduate and community colleges during the major undergraduate education conference of the American Society for Microbiology and at the Gulf of Mexico Research Institute annual conference. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.