In-Vitro Antimicrobial And Antioxidant Potential Of Bacillus Thuringiensis Isolated From Soil

Abstract

It has been well known that Bacillus thuringiensis has insecticidal properties, but there has been growing evidence to indicate that this bacterium has also been producing bioactive metabolites with antimicrobial and antioxidant activities. The goal of the current work was to isolate Bacillus thuringiensis from soil and compare its in vitro antimicrobial and antioxidant potential. Thirty soil samples were obtained. Thuringiensis was found in cultivated and non-cultivated sites. B. thuringiensis isolation was done through the heat shock method, morphological, microscopic, and biochemical characterization. The agar well diffusion technique was used to determine the antibacterial effect of cell-free extracts in relation to Staphylococcus aureus and Escherichia coli. The DPPH free radical scavenging assay was used to determine the antioxidant activity. The isolated strains of B. thuringiensis described had normal morphological and microscopic properties and had Gram-positive, rod-shaped, and sporulating cells with parasporal crystal inclusions. The DPPH test showed that the isolates had moderate to good antioxidant activity, which showed that they had the potential to react as free radical scavengers. Moreover, the cell-free extracts were also found to have inhibitory properties toward both Gram-positive and Gram-negative bacterial pathogens, thereby exhibiting antibacterial properties. The results of this paper provide evidence that soil-derived Bacillus thuringiensis has significant antimicrobial and antioxidant activity, which can justify its use as a source of natural bioactive compounds. Research is also suggested to determine and describe the active metabolites that cause such activities.