Assessment of antibacterial activity of Spirulina platensis cultivated on camel urine medium, in vitro

This research sheds new light on the evolution of microalgae behaviour, specifically their interaction and adaptation strategies to atypical media. The present study was conducted to evaluate the antibacterial activity of Spirulina platensis cultivated in a medium made from camel urine at concentrations of 1:1, 1:2, 1:3 and 1:4 (v:v) during periods (7, 28, and 42 day). The test was performed by the disc diffusion method, against five types of human pathogenic bacteria [Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 10145), Staphylococcus aureus (ATCC 25923), Methicillin-Resistant Staphylococcus aureus and Proteus spp]. Results showed that S. platensis grew and adapted well in most camel urine media, especially in T2 medium with biomass (5.1 g/L), chlorophyll a and b (2.4 and 1.2µg/ml), carbohydrates 40.0% (w/w), and total protein (24µg/ml). In contrast, the bacterial susceptibility test's results were unexpected. The maximum rate of pathogen-bacteria inactivation was attained in the last phase following 42 days. In detail, Significant activity was observed for S. platensis extracts cultivated in low-concentration camel urine medium (T4) against all bacterial species compared to S. platensis extracts naturally cultivated in standard medium. Staphylococcus aureus was the most sensitive species of bacteria to S. platensis extracts with an inhibition zone of 5.0 cm.