Going to extremes to fight oil contamination

JEDDAH — A comprehensive analysis of bacterial communities on Deception Island, an active volcano in Antarctica, highlights the potential for using thermophilic bacteria to clean up oil contamination, according to new research from researchers at KAUST.

Júnia Schultz recently joined KAUST as a postdoctoral student working with Dr. Alexandre Rosado, Professor of Biosciences. Its objective is to characterize the microbiome of extreme terrestrial environments in Saudi Arabia, including volcanoes, deserts and geothermal sites.

These extremophiles, bacteria that thrive in the world’s most extreme environments, including heat-loving ones (thermophiles), hold immense potential for a myriad of biotechnology applications.

“Extremophiles thrive in a multitude of harsh conditions and have adapted to remain metabolically active under harsh circumstances,” Schultz said. “They exhibit versatile and diverse metabolic and physiological capabilities and often synthesize valuable bioproducts.”

These bioproducts include enzymes and bioactive compounds that can be used in industries such as agriculture, pharmacology, and even space exploration. Extremophiles could also provide a safe and effective method of cleaning up hydrocarbon contamination.

“Some bacteria eat petroleum as a source of carbon, nutrients and energy,” she said. “To do this, they first secrete surfactants – substances that break the surface tension of the oil – before absorbing the emulsified oil into their cells, where it is broken down via enzymatic activity.”

For her doctorate, Schultz was curious whether such bacteria exist in the Deception Island volcano in Antarctica. This once-pristine continent is now vulnerable to pollution, including oil contamination, and scientists are hoping to find sources of local bacterial communities that could help with decontamination.

Schultz and his colleagues isolated 126 bacterial strains from samples taken from two geothermal sites on Deception Island.

“These thermophiles could provide valuable and interesting bioproducts, not only for oil decontamination, but for many applications,” Schultz said. “However, it is difficult to mimic the extreme environments in the laboratory to cultivate these bacterial strains. The cell biomass of microorganisms is very low in extreme environments, which makes DNA extraction difficult.

After much perseverance, the researchers were able to collect enough high-quality DNA to perform genomic analysis and cultivate 126 bacterial strains. The genomic characteristics and metabolic potential of seven strains of Anoxybacillus flavithermus were of particular interest.

The team identified genes linked to genome stabilization under temperature fluctuations, heat and cold shock proteins, DNA repair against UV rays and resistance to alkaline conditions, as well as genes for degradation of starch and cellulose.

The team analyzed the 126 strains for their ability to produce biosurfactants and degrade oil. Of these, 76 strains grew well in cultures with crude oil as the sole carbon source. Thirty strains showed particularly good results for oil degradation; 13 of them also produced biosurfactants, including a strain of A. flavithermus.

Oil is one of the most complex pollutants on Earth, and the efficiency of microbial degradation will depend on many factors, from local environmental variables such as temperature and pH, to fractions, amount and composition of the oil present at a given site.

“A comprehensive understanding of local bacterial strains and their metabolic potential is critical to designing future approaches to combat oil contamination, not just in Antarctica, but around the world,” Schultz said.

“I am excited by the potential extremophiles hold, and look forward to exploring the extreme environments of Saudi Arabia for new bioproducts for all kinds of applications.” —SG

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