Evaluation of Antimicrobial and Antioxidant activity of secondary metabolites isolated from endophytic bacterium Bacillus megaterium   isolated from wheat root in Iraq

Abstract

The present study was carried out to find out the antimicrobial activity of endophytic bacteria isolated from wheat plant root by surface sterilization method. Bacterial strain was identified as Bacillus megaterium. Secondary metabolites was carried out by ethyl acetate solvent .Secondary metabolites were demonstrated for antimicrobial activity against Gram-:Negative Bacteria namely; Escherichia coli ,Salmonella typhi and Pseudomonas aeruginosa which range between (16.5-31.0)mm and range between(29.5-33.0)mm against Gram-Positive Bacteria and antifungal activates tested against yeasts test namely; Candida albicans with inhibition zone 16.0mm and 12.0mm against Candida kruzi. Minimum inhibitory concentrations were in the range between (6.25-12.25) and (3.12-25.0) μg/ ml against Gram-Negative and Gram-Positive bacteria respectively and(50)μg/ml against yeasts test and minimal bactericidal concentrations ranged from (12.5 to 25.0) μg/ ml and (6.12-50)μg/ ml against Gram-Negative and Gram--Positive bacteria respectively and minimal fungicidal concentrations (100) μg/ ml against yeasts. The antioxidant activity was analyzed using2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging assays have shown high rates of inhibition .A verification of non-toxicity of the bacterial secondary metabolites against human blood revealed a negative test. The metabolite produced by the endophytic bacteria could be an alternative source of antimicrobial and antioxidants.Keywords: Antimicrobial activity, Antioxidant activity, Endophytic bacteria, bacteria.