The ocean is teeming with life, however much of it is still unknown to science. Bluetools partners at the University of Alicante have recently shed light on a previously uncharacterised group of bacteria within the Gemmatimonadota phylum. These bacteria, among the most frequently retrieved Gemmatimonadota in marine samples, were largely a mystery in terms of their physiology and ecological roles—until now.
In a study published in mSystems, the authors characterise this group and propose a new order for it, Palauibacterales, within the Gemmatimonadota phylum. Their research reveals that these bacteria are not only widespread in marine environments, but also may play a crucial role in nutrient cycles due to their ability to metabolise nitrous oxide (N2O) and produce vitamin B1 (thiamine).
Nitrous oxide is a potent greenhouse gas, with a global warming potential around 300 times greater than CO2. Some Palauibacterales species possess the genetic ability to metabolize N2O, potentially mitigating its harmful effects. At the same time, thiamine is an essential nutrient for many marine organisms, yet it is often in short supply as many species cannot produce it themselves. The study provides evidence that Palauibacterales can synthesise thiamine, suggesting they may help sustain marine ecosystems by supplying this vital nutrient where it is scarce.
Beyond their role in nutrient cycles, Palauibacterales have shown resilience in heavy-metal-contaminated environments. A study of sediments from Spain’s Mar Menor lagoon found that these bacteria were particularly abundant in heavy-metal contaminated areas, suggesting they have mechanisms to withstand and possibly neutralize these metals. This raises the possibility that Palauibacterales could aid in the natural recovery of polluted marine ecosystems. Microorganisms capable of neutralising heavy metals are of great interest for bioremediation—the use of biological organisms to remove environmental pollutants. If future studies confirm that Palauibacterales actively contribute to detoxifying contaminated sediments, they could become a valuable tool for restoring contaminated marine habitats.
Palauibacterales may also be interesting for medicine. Researchers identified biosynthetic gene clusters (BGCs) in these bacteria that resemble those responsible for producing bioactive compounds, including Azinomycin B, a potent antibiotic with antitumor properties; Cyphomycin, an antifungal compound; and Vazabitide A and Funisamine, bioactive molecules with yet-to-be-determined properties. These findings suggest that Palauibacterales could serve as a new reservoir of bioactive molecules for future drug discovery and development.
Widely distributed across the world, in deep and shallow aquatic environments, Palauibacterales have been more abundantly detected in marine sediments, soils and sponges. Their ability to thrive in diverse environments indicates they may play a key role in marine ecosystems.
This discovery offers some insight on the ecological importance of Palauibacterales and their potential applications in climate change mitigation, ecosystem restoration, and medicine. Read the full study in mSystems.