OKEANOS

Published in Microorganisms, the review article “Deciphering Macroalgal Microbiomes: Metagenomic Insights, Ecological Roles and Bioprospecting Potential” explores the complex relationships between macroalgae and their associated microorganisms, examining their ecological functions and biotechnological potential.

Macroalgae host diverse microbial communities that may contribute to processes such as host development, nutrient cycling, carbohydrate metabolism, environmental responses and the production of bioactive compounds. A central theme of the review is the need to distinguish between functional potential inferred from metagenomic data and biological activity that has been experimentally demonstrated.

The article also examines the growing biotechnological relevance of macroalgal microbiomes, including carbohydrate-active enzymes, polysaccharide-utilization systems and biosynthetic gene clusters with potential applications in marine biotechnology and bioprospecting.

An important component of the paper is an illustrative case study based on shotgun metagenomic datasets from two brown macroalgal holobionts from the Azores, Rugulopteryx okamurae and Sargassum sp. The analysis shows how dominant bacterial taxa, particularly Cobetia, can influence the interpretation of community-level functional profiles and highlights the importance of linking predicted functions to the microorganisms encoding them.

Importantly, this case study is presented as hypothesis-generating rather than as evidence of general species-wide differences, reinforcing the need for stronger biological replication and integration of metagenomics with other omics approaches and experimental validation.

Overall, the review argues that macroalgal microbiome research should move beyond asking “Who is there?” and “What could they do?” towards determining which microorganisms perform particular functions, under which environmental conditions, and with what consequences for the host.

This publication also represents the first scientific paper of PhD student João Moreira.

The article is available in open access:

Moreira, J., & Bettencourt, R. (2026). Deciphering Macroalgal Microbiomes: Metagenomic Insights, Ecological Roles and Bioprospecting Potential. Microorganisms, 14(10), 2127.

https://www.mdpi.com/2076-2607/14/10/2127

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