Antibiofilm activity of biosurfactant produced by a sponge-associated marine Cobetia sp. JCG-23

Marine symbiotically associated microbes play a vital role and are an excellent source of natural compounds that exert wide biological activities. In this study, we have reported on the identification, characterization, phylogenetic relationship, and anti-biofilm surface-active compound-producing abilities of marine invertebrate sponge-associated Cobetia sp. JCG-23. Among 24 isolates, a total of five strains (JCG2, JCG19, JCG20, JCG22, and JCG23) have active surface molecule producing potential on the emulsification index assay. Interestingly, the potential candidate JCG-23, produces biosurfactants with low surface tension (22 Nm(-1)) that exert anti-biofilm activity against Pseudomonas aeruginosa PAO1. The isolate was identified as genus Cobetia sp. JCG-23 with 99.1% sequence similarity to Cobetia crustatorum (EU909460) based on 16S rRNA gene sequence analysis. The large-scale production, purification, stability, and characterization of biosurfactant were carried out and its surface activity was determined using the oil drop method. Subsequent spectral analysis such as UV, FT-IR, and GC-MS analysis indicated that the purified biosurfactant was a hydroxyl fatty acid, namely octadecanoic acid (C18H36O2) with a molecular weight of 284 m/z. Furthermore, the effect of antibiofilm activity on the viability of Pseudomonas aeruginosa PAO1 by static ring tube and light and confocal laser scanning microscopy analysis revealed that the octadecanoic acid from Cobetia sp. JCG-23 has strong biofilm dismantle ability against Pseudomonas aeruginosa PAO1. Further characterization of the biosurfactant from the isolate Cobetia sp. JCG-23 can pave the way for developing novel bioactive agents targeting biofilm-forming pathogens on topical and medical devices.