Evaluation of Antibacterial Activity of Solvent Extracts of Spirulina fusiformis against Pathogenic Bacterial Strains

This study explores the antibacterial properties of Spirulina fusiformis, a blue-green alga with significant dietary and medicinal value. Spirulina is recognized globally for its nutrient-rich composition and potential therapeutic applications. With antibiotic resistance emerging as a serious global health concern, algae-derived bioactive compounds offer a promising, natural alternative to traditional antibiotics due to their non-toxic profile and effectiveness against pathogenic bacteria. The antibacterial activity of S. fusiformis was assessed using various solvent extracts, including petroleum ether, benzene, ethyl acetate, methanol, and ethanol, tested against twelve bacterial strains, including Bacillus thuringiensis, Staphylococcus aureus, Streptococcus pyogenes, and Escherichia coli, using the well diffusion method. Results showed that the ethanol extract of S. fusiformis exhibited the highest antibacterial activity, inhibiting all tested bacteria, with the greatest zones of inhibition observed against Streptococcus pyogenes (17 mm) and Bacillus thuringiensis (16 mm). The presence of some significant antimicrobial compounds present in the ethanol extract. These findings support the use of Spirulina fusiformis as a natural antibacterial agent and underline its potential in developing alternative therapeutic strategies for combating antibiotic-resistant pathogens.