Abstract
Extracts of Chlorella vulgaris prepared by using three solvent; methanol, chloroform and diethyl ether, were evaluated for the antimicrobial potential. The extracts were tested against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25928, Streptococcus pyogenes grp A (clinical isolate), Bacillus subtilis ATCC 6633. The findings revealed that the extracts were able to inhibit the growth of one or more tested pathogen. The diethyl ether extract showed the maximum zone of inhibition (28.6 mm) against E. coli whereas these extracts were ineffective against P. aeruginosa and S. aureus. The MIC of diethyl ether extract was 0.6 mg/ml against E. coli and S. pyogenes whereas, the MIC of acetone extract was 1.0 mg/ml for B. subtilis. The scanning electron microscopy (SEM) was used to examine the morphological changes in E. coli induced by diethyl ether extract of C. vulgaris. The treated E. coli cells were deformed, their surfaces were rough and depressions in some cells were also observed. The GC-MS analysis of extract detected the presence of Heptanal, a known biomedical compound. The other major components of the extract were 2-Butanol, 3-Methyl-, (S)-; 2-Hexanol, (S)-; (3R, 2E)-2-(Hexadec-15-Ynyliedene)-3-Hydroxy-4-Methylenebutanolide; 4-Methyldocosane. Thus, it can be concluded that extracts of C. vulgaris, have the potential to be explored for antibiotic production. Further, efforts should be made to identify the compounds directly responsible for antibacterial properties.