Abstract

ABSTRACT Marine microalgae has been attracting the researcher's attention for centuries. Development on microalgal research is majorly favoured by its medicinal, pharmaceutical or cosmeceutical properties. The advancement in the investigation related to microalgal products have been concentrated in the coastal zones because of the greater supply of raw material. The Southern Ocean, highly productive and relatively poorly studied ecosystem, constitutes approximately 10% of the global volume of the oceans. In this study, marine microalgae Chlorella sp. PR-1 was isolated from the Southern Ocean (Indian Sector) for the identification of bioactive antibacterial compounds. The antimicrobial activity of this microalgal extracts was evaluated against three gram positive (Staphylococcus aureus, Bacillus licheniformis, and Bacillus subtilis) and three gram negative bacteria (Pseudomonas aeruginosa, Salmonella typhimurium, and Escherichia coli). The extract showing antibacterial activity was further purified by thin layer and column chromatography. The antimicrobial activity was again evaluated and confirmed with the purified fraction against the same bacteria. The identification of the functional groups in the purified fraction was performed by infrared spectroscopic analysis. Based on gas chromatographic and mass spectroscopic analysis, the principle bioactive compound was proved to be 2,4-bis (1,1-dimethylethyl)- phenol. Thus, the bioactive compound isolated from marine microalga of Southern Ocean origin may be a novel alternative source of antibacterials in the future.