Endozoicomonas lisbonensis is the name of a novel bacterium discovered by Técnico researchers in partnership with Oceanário de Lisboa. The research article was published on 5 March.

The discovery and identification of this new bacterium is the result of the research developed by Daniela Silva, Matilde Marques and Joana Couceiro, master’s and doctoral students at Técnico, accompanied by Tina Keller-Costa and Rodrigo Costa, researchers at the Institute for Bioengineering and Biosciences (iBB), a research unit affiliated with Técnico, Núria Baylina and Elsa Santos, Head of Biology and Conservation and Head Aquarist at Oceanário de Lisboa, respectively.

Endozoicomonas are coral symbionts – the two organisms interact in a mutually beneficial way. In particular, E. lisbonensis is distinguished from nearby species by its ability to reduce nitrates to nitrites, contributing to one of the most important nutrient cycles in the ocean (and essential to coral health), the nitrogen cycle.

The bacterium was first isolated in 2022, but it was only after a complete sequencing of its genome that researchers confirmed it has a new species. It thrives in salty environments, possesses a small structure called a flagellum that allows it to move and swim and is classified as a facultative anaerobe, meaning it can grow in both the presence and absence of oxygen.

Endozoicomonas lisbonensis under microscope.

Another characteristic of this bacterium is its ability to degrade complex carbohydrates common in the environment, including cellulose, xylan and chitin. ‘Our interest is particularly centred on the degradation of chitin, both for its biotechnological potential – such as the discovery of new enzymes that could help recycle waste from the shellfish industry – and for its possible role in the interaction with corals’, says Tina Keller-Costa.

Corals feed on a diet rich in chitin, suggesting that these microorganisms may help make nutrients accessible to their host. In addition, chitin and the enzymes that break it down (chitinases) may be involved in communication between bacteria and corals or even in defence against fungal pathogens. ‘However, many of these hypotheses still need to be tested’, says the researcher. ‘Understanding the exact mechanisms and evolutionary factors behind these interactions is what we’re most excited about.’

The cells and colonies of E. lisbonensis are generally very small and can easily go unnoticed. Additionally, they tend to grow slowly in the laboratory, which makes them easily overtaken by other faster-growing bacteria in cultivation – many species of this group of bacteria are still unable to be cultivated in the laboratory, probably because they need very specific conditions or nutrients that they receive from their marine hosts. ‘Recreating these conditions outside of their natural environment can be quite difficult. Part of our research focuses precisely on overcoming this cultivation bias by developing new ways of cultivating bacteria that until now were unable to grow in the laboratory. This allows us not only to better understand their role in the ecosystem and explore their biotechnological potential, but also to contribute to preserving our planet’s microbial diversity,’ Keller-Costa shared.

The iBB team is very interested in the study of marine microbial diversity, both from the point of view of fundamental research and its possible applications. Much of their work centres on microorganisms associated with marine animals, including corals – both those that live in natural environments and those that inhabit artificial ecosystems, such as Oceanário de Lisboa.

‘Aquariums contribute to the study of many species that are difficult to monitor and study in the wild, as is the case with this bacterium’, says Núria Baylina, emphasising that ’studies carried out with species in controlled environments (ex situ) complement those carried out in the wild (in situ) and the combination of the two approaches make it possible to make faster progress in scientific knowledge about the species, their role in the balance of ecosystems and the threats they face.’

‘Exploring the coral microbiome at Oceanário de Lisboa is particularly exciting’, says Tina Keller-Costa, ’because it help us understand the stability of the relationship between corals and their microbial partners.’ Additionally, the characterisation of the microbiome conducted at Oceanário de Lisboa can help to monitor and better understand potential microbial diseases within the system, allowing for the development of effective strategies for their prevention and mitigation.

In the Media:

• “Descoberta uma nova espécie de bactéria em corais do Oceanário de Lisboa” – Com Tina Keller Costa (Público)
• “Cientistas do Técnico descobrem nova espécie de bactéria em corais do Oceanário” (LUSA)
• “Cientistas do Técnico descobrem nova espécie de bactéria em corais do Oceanário” (Sapo 24)
• “Cientistas do Técnico descobrem nova bactéria em corais do Oceanário” (Notícias ao Minuto)
• “Investigadores do Técnico descobrem nova espécie de bactéria simbiótica em corais do Oceanário de Lisboa” (Greensavers)
• “Cientistas do Técnico descobrem nova espécie de bactéria nos corais do Oceanário” (CNN)
• “Nova espécie de bactéria descoberta em corais do Oceanário de Lisboa” – Com Tina Keller Costa (TSF)
• Cientistas do Técnico descobrem nova espécie de bactéria em corais do Oceanário (Observador)
• Cientistas do Técnico descobrem nova espécie de bactéria nos corais do Oceanário (Tvi Notícias)
• “Nova espécie de bactéria simbiótica descoberta por investigadores do Instituto Superior Técnico em corais do Oceanário de Lisboa” (Gazeta Rural)