Comparative metagenomic analyses of the microbiome from three Mediterranean sponges to identify genes involved in biosynthesis of bioactive compounds

Marine sponges host a range of microorganisms and among them, bacteria represent a significant part of their biomass. Furthermore, bacteria are promising sources of natural products to be applied in various fields. Often the study their biotechnological potential is relented by low grow rates. For this reason, such cultivation-independent approaches, as metagenomics tools applied to sponges is obtaining wide success. For the first time, here we aimed at having an almost complete information about taxonomic and functional diversity of bacteria associated to three sponges, Agelas oroides, Haliclona (Halichoclona) vansoesti and Geodia cydonium, previously reported as candidate sources of bioactive compounds for pharmacological, nutraceutical and cosmeceutical purposes. Comparative metagenomic analyses were applied, sequencing DNA from the three sponges by ONT GridION X5 Mk1 sequencer. Our findings revealed for all the analyzed sponges the presence of genes/enzymes responsible for the synthesis of vitamins, fatty acids, antioxidant glutathione, terpenes, steroids and carotenoids. Consequently, we demonstrated the three sponges under analysis and their associated microorganisms could be considered good candidates for the isolation and identification of bioactive compounds for biotechnological application in the field of pharmacology, nutraceuticals and cosmeceuticals as well as environmental biotechnologies. Overall, metagenomic data represent a useful tool exploitable to sustainably develop bioactive products.