Impact of growth media and pressure on the diversity and antimicrobial activity of isolates from two species of hexactinellid sponge.

Access to deep-sea sponges brings with it the potential to discover novel antimicrobial candidates, as well as novel cold- and pressure-adapted bacteria with further potential clinical or industrial applications. In this study, we implemented a combination of different growth media, increased pressure and high-throughput techniques to optimize recovery of isolates from two deep-sea hexactinellid sponges, and sp., in the first culture-based microbial analysis of these two sponges. Using 16S rRNA gene sequencing for isolate identification, we found a similar number of cultivable taxa from each sponge species as well as improved recovery of morphotypes from at 22-25 °C compared to other temperatures, which allows a greater potential for screening for novel antimicrobial compounds. Bacteria recovered under conditions of increased pressure were from the phyla , and , except at 4 %O/5 bar, when the phylum was not observed. Cultured isolates from both sponge species displayed antimicrobial activity against and .