Determination of antimicrobial activity of Chlamydomonas reinhardtii extracts obtained with different solvents

Ramírez, Roxana Olvera and Jaritz, Nora Beatriz Medina and López, Margarita Pineda (2025) Determination of antimicrobial activity of Chlamydomonas reinhardtii extracts obtained with different solvents. Open Access Research Journal of Life Sciences, 9 (1). 027-031. ISSN 2783-025X

The abuse in the use of antibiotics has resulted in the selection of bacterial strains with resistance to them, making it evident that new classes of antibiotics are needed, with novel structures to combat this trend, for this reason is necessary to find alternative sources. There are natural products, such as those obtained from green algae, that have an inhibitory effect against various pathogenic bacteria; this group of algae includes the genus Chlamydomonas. The objective of this work was to determine if extracts of the green algae Chlamydomonas reinhardtii made with some solvents have antimicrobial activity. C. reinhardtii was propagated in BG-11 medium; under optimal light conditions (photoperiod of 16 h light: 8 h dark), constant aeration and temperature of 28 °C; the biomass was harvested and the extracts were made by adding 1g of wet biomass to a volume of 3mL of the following solvents: hexane, methane and ethyl acetate, and the determination of the antimicrobial activity was carried out by the Kirby-Bauer method. The microorganisms used were Staphylococcus aureus ATCC 259223, Pseudomonas aeruginosa ATCC 9028, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 8739 and Salmonella typhi ATCC 6534. It was found that the extracts obtained with methanol and hexane at the two concentrations used (23µg/70µL and 33µg/100µL) showed antimicrobial activity against the 5 ATCC strains used, when testing the concentration of 33 µg/100µL, a greater inhibition was found; the extract obtained with ethyl acetate did not show activity against any of the ATCC strains.