Evaluation of antimicrobial activities of microalgae Scenedesmus dimorphus extracts against bacterial strains

The study was conducted to analyze the existence of bioactive phytochemicals extracts in green alga Scenedesmus dimorphus and their antimicrobial role. Various solvents such as methanol, ethanol, N-hegzane and diethylether were used for extraction. The extracts of of Scenedesmus dimorphus were tested against two Gram - positive bacteria (Bacillus subtilis and Micrococcus luteus), a Gram - negative bacterium (A. hydrophila) and Escherichia coli by the agar well diffusion method. Four different methanolic, ethanolic, hexane and diethylether extracts showed effective inhibition against different bacterial pathogens. Diethylether extract was very effective against bacterial strains compared to other extracts. Methanolic extract effectively inhibited A. hydrophila in comparison with other extracts, while ethanolic extract did not have any inhibitory effect on the bacterium. Methanolic, ethanolic, hexane and diethylether extracts were analyzed by GC mass. The most abundant compounds in methanolic extract of S. dimorphus included esters, plasticizer compound and terpens, while in the ethanolic, N-hexane and diethylether extracts, the most abundant compounds were found to be plasticizers, hydrocarbon and esters. These results indicate the presence of promising antimicrobial compounds in the examined algal species. Further phytochemical studies are required to elucidate the structutre and detailed activities of these compounds. So, we achieved antimicrobial activity in the methanolic, ethanolic, hexane and ether extracts of green microalgae against some pathogenic bacteria as well as employing GC mass autogram for S. dimorphus extracts for preliminary detection of active constituents.