Antimicrobial Activity of the Heterocytous Cyanobacterium Westiellopsis prolifica and Assessment of Its Microcystin–LR Biosynthesis

Abstract

THE HETEROCYTOUS cyanobacterium Westiellopsis prolifica has been recently documented in Egypt; however, our understanding of its diverse biotechnological and biomedical applications remains a limited and challenging topic. In this study, a W. prolifica strain isolated from hyper-arid desert habitats was investigated to test its antimicrobial potential against six foodborne pathogenic bacteria (Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, and Klebsiella pneumoniae) and eight mycotoxigenic fungi (Aspergillus carbonarius, A. flavus, A. niger, A. ochraceus, A. parasiticus, A. westerdijikia, Fusarium proliferatum, and Penicillium verrucosum), as well as to evaluate its probable toxicity and biosynthesis of the most common microcystin variant (MC–LR) using high-performance liquid chromatography (HPLC). The antimicrobial activity of various W. prolifica extracts was assessed using the disk–diffusion method, and the minimum inhibitory concentrations (MICs) were also determined. Our findings revealed that the extracts of dryland-dwelling W. prolifica had significant antimicrobial activities against all tested bacterial and fungal strains, with average MIC values of 0.4–6.7 and 0.3–9.2mg.mL−1, respectively. This antimicrobial potential can be ascribed to the combined synergistic effects of its biologically active and structurally diverse metabolites. Moreover, this species was a non-producer of MC–LR and was non-toxic based on the brine shrimp bioassay. Thus, the cyanoprokaryote W. prolifica can be considered a sustainable multifunctional candidate in the development of the pharmaceutical industry in Egypt.