Characterization and identification of isolated bacteria from ice-ice disease infected seaweed Kappaphycus alvarezii

Ice-ice disease occurs in cultivated algal seaweed Kappaphycus alvarezii due to pathogenic bacterial infections. This seaweed has rich source of carrageenan widely known as the kappa carrageenan. Generally, ice-ice disease leads to whitening of the branches initiated with colour changes of the thalli, which become transparent in the end. This study was aimed to isolate and identify the bacteria based on morphology and biochemical characterization on ice-ice diseased K. alvarezii from three different places, namely, Kottapatinam, Thondi and Rameswaram. The bacterium was isolated in Zobell Marine Agar (ZMA) and thiosulfate-citrate-bile saltsucrose (TCBS) agar. Morphological and biochemical characterizations revealed that the isolated bacteria causing ice-ice disease were closely related to the genera Bacillus in ZMA and Vibrio species in TCBS. Total viability count, physical and chemical properties of the bacteria by gram staining and morphological analysis were done for all species isolated from three places.