Evaluation of inhibitory potential of mangrove leaves extract Avicennia marina for bacteria causing ice-ice diseases in seaweed Kappaphycus alvarezii

Today, the problem of seaweed is the emergence of ice-ice disease, which causes economic losses. The solutions offered at this time are not significant, so there is a need for technology that can control the ice-ice disease. The effort is to use mangrove leaves to extract Avicennia marina. This study aimed to evaluate the inhibitory potential of mangrove leaves extract A. marina against bacteria that cause ice-ice disease in seaweed. Four pathogenic bacteria that cause ice-ice in seaweed, namely Stenotrophomonas maltophilia strain IAM 123, Shewanella haliotis strain DW01, Vibrio alginolyticus strain ATCC 17749 and Pseudomonas aeruginosa strain SNP0614 were tested using A. marina leaves extract with methanol solvent, the method used is the maceration method and antibacterial activity test using the Kirby-Bauer method with seawater complex (SWC) agar. The results showed phytochemical compounds found in A. marina leaves extracts, namely alkaloids, saponins, tannins, phenolics, flavonoids, triterpenoids, and glycosides. A. marina leaves extract using methanol solvent shows potential as an antimicrobial which is indicated by inhibition zones in each of the bacteria that cause ice-ice.