Preliminary Studies on Antimicrobial Activity of Selected Marine Micro Algal Extracts Against Human Pathogens

Five species of micro algal cultures were collected from Central Marine Fisheries Research Institute, Tuticorin, Tamilnadu. The collected micro algal species, Isochrysis galbana, Dunaliella saline, Tetraselmis tetrahele, Chlorella salina, and Nannochloropsis sp. were mass cultured in Walne's medium. Ten strains of bacteria, Enterococcus faccalis, Bacillus subtilis, Staphylococcus aureus, Enterobacter aerogens, Streptococcus epidermidis, Shigella boydii, E.coli, Proteus vulgaris, Pseudomonas aeruginosat and Klebseilla pneumonial, three strains of fungi Aspergillus sp. Mucor sp., and Candida sp. were used for the antimicrobial study. Among the total 5 micro algal extracts used against the ten bacterial pathogens, only three pathogens S.aureus, E.coli, P. aeruginosa showed inhibition. Isochrysis galbana extract showed maximum inhibition when compared to other extract. In the antifungal study, Aspergillus sp., Mucor sp., and Candida sp. showed inhibition. Isochrysis galbana extract showed maximum inhibition when compared to other extract. Among the 3 different solvent used ethanol showed maximum extraction of antimicrobials. On the basis of anti microbial activity the ethanol extracts of I. galbana, D. saline and T. tetrahele were selected for preliminary phyto-chemical analysis. It showed the presence of sterols, carbohydrates, proteins, fixed oil and fats. From this study it was clear that the solvent played an important role for extracting the particular antimicrobials from marine plants and the sterols played an important role in the antimicrobial activity of selected algal species.