Screening for Antibiotic-Producing Fungi from Soil in Caleb University, Imota, Lagos, Nigeria

Abstract

Antibiotics are chemical substances of biological, synthetic, or semi-synthetic origin, playing important roles in culture techniques, molecular biology, biochemistry, microbiology, genetics and pharmacology. Natural antibiotics are produced by certain microorganisms that can inhibit or suppress the growth of other microorganisms. Antibiotics are the most important microbial secondary metabolites and as a result, antibiotics are the most commercially exploited microbial secondary metabolites with obvious relevance to modern medicine and biotechnology. Since the discovery of antibiotics, over-dependence on antibiotics has led to the emergence of antibiotic-resistant microorganisms. Hence, there is an increasing demand for antibiotic-producing fungi from soil. Soil samples were sourced from seven (7) different sites and the collected soil samples were labeled J, C, DS, L, AB, G, F, LG and SIG. Isolation and screening of isolate were performed using standard procedures. This study reveals that Samples from the Laboratory garden and the school's inner garden had colonies that were too numerous to count while samples from the laboratory garden had the lowest number of colonies. Results from growth on plates show that fungi were abundantly distributed in both clay and loam soils. A total of 7 fungal isolates were selected. Antimicrobial activities against clinical isolates of Staphylococcus aureus and Escherichia coli were confirmed. In conclusion, it was deduced from this study, that Penicillium and Aspergillus species were isolated from soils sourced from Caleb University However, penicillium had no inhibitory activity against Staphylococcus aureus and Escherichia coli.