ANTIBACTERIAL ACTIVITY SCREENING OF BACTERIAL ISOLATES ASSOCIATED WITH SEAWEEDS Caulerpa lentillifera

Abstract

Background: Caulerpa lentillifera is a species of green algae that has been cultivated widely in Indonesia for its nutritional contents and health benefit. This seaweed builds a strong association with bacterial community which play an important role in synthesizing various secondary metabolites including antibacterial activity. Aims:The research aim to explore the symbiotic relationship between C. lentillifera and its associated bacterial community, focusing on the potential of these bacteria to produce antibacterial metabolites.Methods:Bacterial cultivation was performed on three different media namely nutrient agar, plate count agar, and zobell marine agar. The obtained bacterial isolates were identified morphologically and subsequently were screened for their antibacterial activity based on perpendicular cross streak method against Staphylococcus aureus ATCC 25923, Streptococcus mutans FNCC 0405, Escherichia coli ATCC 25922, and Klebsiella pneumoniae ATCC 700603. Results: 20 out of 28 bacterial isolates inhibited against at least one of the bacterial targets. Bacterial isolate encoded as NAR9 showed as the most promising bacterial isolates with length inhibition of 19 mm against S. mutans FNCC 0405. Amplification of 16S rRNA gene fragment of the NAR9 bacterial isolate followed by Sanger sequencing showed that the isolate NAR9 has been phylogenetically related to Marinobacter hydrocarbonoclasticus. Conclusion: Overall, this research provides a preliminary result of the untapped potential of bacteria associated with C. lentillifera as the source of antibacterial activity.