7 March 2024

Cold-resistant bacteria can degrade oil in the Arctic

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The Russian study: some bacteria decompose biopolymers and hydrocarbons and convert phosphates into soluble forms. In this way they contribute to the decontamination of permafrost

by Matteo Cavallito

 

Some bacteria could contribute to the bioremediation of Arctic soils from fossil fuel contamination. This is suggested by a study published in the journal Microorganisms. “The Arctic chronically suffers from the consequences of human activity,” said Vladimir Myazin, a researcher at RUDN, the Peoples’ Friendship University of Russia, and co-author of the research, in a statement released by the researchers.

“In addition to climate change,” he added, “the industrial development of the region has a negative impact. It has led to increased anthropogenic pollutants, which are very difficult to combat in northern conditions.” The allusion is to the characteristics of permafrost, which blocks hydrocarbons in the soil, making them difficult to remove.

Bacteria grow even in the cold

The investigation examined four strains of bacteria from the genera Pseudomonas, Rhodococcus, Arthrobacter and Sphingomonas. The microorganisms were detected in oil-contaminated soils on the island Land of Alexandra within the Franz Joseph Land archipelago in the Arctic Ocean. These bacteria, the researchers explain, are “capable of growing at low temperatures and degrading oil and petroleum products.”

In the laboratory, the bacterial strains “grew on hydrocarbons at temperatures from −1.5 °C to 35 °C in the presence of 0–8% NaCl.”

During the experiments, the bacteria showed that they can grow rapidly not only in summer but also in cold conditions when other microorganisms are inactive. In particular, they decompose natural biopolymers (xylan, chitin) and acyclic hydrocarbons with a linear or branched structure, the alkanes. In addition, they also convert phosphates to soluble forms.

Microorganisms contribute to Arctic decontamination

The ability to degrade alkanes is particularly rare among bacteria in the genus Sphingomonas. Analysis of the genome of the isolated strain, the research explains, “showed the presence of genes encoding enzymes of n-alkane oxidation, pyruvate metabolism, desaturation of membrane lipids, and the formation of exopolysaccharides, confirming the adaptation of the strain to hydrocarbon pollution and low habitat temperature.”

This analysis and empirical observations, the study continues, “indicate the possible participation of the studied strains in the self-purification of Arctic soils from hydrocarbons and their potential for biotechnological application in bioremediation of low-temperature environments.”

Oil and bioremediation

The results of the study join the contributions of other research that has highlighted the potential of various microorganisms in aiding natural soil decontamination. A few years ago, for example, a University of Wisconsin study highlighted the ability of certain fungi to absorb heavy metals in polluted soils, leading to their remediation.

More recently, a study by the University of Alaska Fairbanks, suggested that a proper combination of grasses and fertilizers could enhance the ability of plants and their associated microbes to remediate oil-contaminated soils. The scientists’ hypothesis is that once placed in a contaminated site, certain plants are able can select microbes that can alleviate the stress induced by the presence of petroleum hydrocarbons.