Sponge-Associated Bacteria: Isolation, Phylogenetic Analysis and Biotechnological Potential

Abstract

Marine sponge Hyrtios erectus is a source of numerous toxic secondary metabolites, which are considered as products of the symbiotic species associated with the sponge. Sponge-associated bacteria have great potential in developing marine pharmaceutical industry since they are capable of synthesizing numerous bioactive metabolite compounds. This study aimed to isolate the associated bacteria, characterize their different secondary metabolite , and investigate their potential antioxidant and cytotoxicity activities. Sponge was taxonomically identified as Hyrtios erectus. Moreover, taxonomic and phylogenetic analyses of the bacteria on the basis of 16S rRNA gene sequences showed that the dominant two phyla were Firmicutes and proteobacteria. The results of HPLC analysis revealed that Chlorogenic acid, Coffeic acid, and 3,5-Dicaffeoyl quinic acid were the main phenolic compounds present in the HA-MS-22 [JX494759] crude extract, whereas Chlorogenic acid and 3,5-Dicaffeoyl quinic acid were present in the HA-MS-21 [JX494761] crude extract. Moreover, extract HA-MS-22 [JX494759] did not contain gallic but contained tannic. In the meantime, extract HA-MS-21 [JX494761] contained both gallic and tannic acids. The highest level of total phenolic contents was shown in extracts HA-MS-22 (3.702 ±0.10 mg gallic equivalent/ml).Whereas, the lowest value was shown in extract HA-MS-23 (3.015±0.045 mg gallic equivalent/ml). Significantly high concentration of total flavonoids (11.16±0.46 mg catechin equivalent/ml). were measured in the ethyl acetate JX494761 extract. The JX494759 crude extract contained also considerably high contents of total flavonoids (7.61±0.003 mg catechin equivalent/ml). Carotenoid compounds significantly varied among the two bacterial extracts; the highest total carotenoid concentration was shown in extract HA-MS-22 (0.048µg/ml). Whereas, lower values were shown in extracts JX494761 (4.098µg/ml). In the meantime, GC/MS profiling for the ethyl acetate extract of the studied sponge-associated bacteria revealed the presence of various phytochemical compounds having different biological activities. Results of FTIR spectroscopic studies have revealed the presence of various chemical compounds. The presence of O