Growth dynamics and biotechnological potential of bacterial isolates from Raspaciona aculeata

Marine sponges are a reservoir of microbial diversity and host many species-specific bacterial symbionts that maybe of great biotechnological interest. This research constitutes the first characterization of the growth dynamicsof the bacterial community associated with the marine sponge Raspaciona aculeata, to evaluate the effects ofincubation temperature on its biotechnological potential. Fifty-two strains were isolated from R. aculeata ho-mogenate and five potential morphological strains were identified based on different morphological features ofthe colonies (shape, color, margins and size) and subsequent confirmation by rRNA analysis. 16S rRNAsequencing revealed that all bacterial isolates belonged to the Pseudomonadaceae and Pseudoalteromonadaceaefamilies. The bacterial strains were grown in Marine Broth medium at different growth temperatures (4, 15, 25,and 37 ± 1 ◦ C) for up to 50 days. Changes in cell hydrophobicity (polystyrene adhesion assay) and surfactantproduction (emulsion activity, %, E24) were correlated with growth measurements (optical density, OD600nm).The results highlight that although temperature represents an important natural factor in adhesion processes, thisdid not generally influence growth dynamics. The highest emulsification activity values were recorded withaverage values of approximately 29 % (%, E24) among all strains studied at a temperature of 15 ◦ C and values ofapproximately 30 % (%, E24) at a temperature of 25 ± 1 ◦ C. The ability of the bacterial strains to degrade crudeoil, tetradecane and phenanthrene at the different temperatures under study was also analyzed, with the averagevalues among all strains under study being higher (by approximately 49 %, 46 %, and 50 %, respectively) at atemperature of 25 ± 1 ◦ C. These findings suggest that the sponge-associated bacterial strains isolated in this studyare actively involved in surfactant production and hydrocarbon degradation, and could be further investigatedfor their possible application in bioremediation processes.