Bacterial colonies were marooned by water samplings from Machilipatnam coasts,Andhra Pradesh in South India. The isolates were cultured and analyzed for antimicrobial action. Among the 40 isolating evidences, 10 isolates showed substantial antibacterial activity with more than 10 mm of zone of inhibition at least against one test organism. Those bacteria were analyzed based on their morphological, biochemical and physiological characteristics. From all the isolates collected and studied only three strains showed the most outstanding results almost against all the test bacteria. These three isolates were marked as M20, M22 and M23 and the strains were found to be Alcaligens sp. (M20), Bacillus sp. (M22) and Bacillus sp. (M23) from the performed biochemical tests. The extracts of Alcaligens sp. (M20) showed the highest activity among the selected isolates with a zone of inhibition of 16mm at 150 µg/ml against Serratia marcescens. Meanwhile, it showed a zone of inhibition of 14 mm against E.coli and Shigella, whereas 12 mm against Salmonella paratyphi and Bacillus cereus.
Key words: Crude Extracts, Antibacterial Activity, Secondary Metabolites, Carbon Source Utilization
|
