Antifouling activity of marine epibiotic bacterium <i>Bacillus flexus</i> APGI isolated from Kanyakumari Coast, Tamilnadu, India

Abstract

In this study, an attempt has been made to explore the antifouling activity of newly isolated seaweed epibiotic bacterium <i>Bacillus flexus</i> APGI. Antimicrofouling activity of ethyl acetate extract of <i>B. flexus</i> APGI inferred that, it exhibited pronounced inhibitory zones against fouling bacterial strains (5 to 14 mm) with least minimal inhibitory concentration (MIC) ranged between 25 and 100 µg ml^-1. Antimacrofouling activity results showed that, the MIC of ethyl acetate extract for complete inhibition of byssal thread production and attachment of mussel <i>Perna indica</i> was found to be 108 µg ml^-1. Further, EC₅₀ < LC₅₀ and 100% recovery of <i>P. indica</i> in toxicity assay propagated the non-toxic nature of the extract. Anticrustacean assay using <i>Artemia salina</i> larvae registered LC₅₀ value of 835 µg ml^-1. Analysis of chemical constituents suggested the presence of mid polar components such as alkaloids, coumarins and quinones in the extract. This study tends to indicate that, <i>B. flexus</i> APGI could be potentially explored for the development of new antifouling agents.