Investigating the Influence of Culture Conditions on Antimicrobial Activity of NC01 Strain

Abstract

Myxococcus sp. is an important large genus in the family of myxobacteria because it is considered a prospecting source of secondary metabolites. This study aims to: (i) Identify potential NC01 strain by morphological, biochemical and 16S rDNA gene sequences; (ii) Evaluate antimicrobial activity by agar well-diffusion and microdilution methods; (iii) Survey medium and fermentation conditions that exhibit the best antimicrobial activity and (iv) Determine active fractionation by thin-layer chromatography (TLC) bioautography. The results show that the NC01 strain was designated Myxococcus fulvus. This strain demonstrated inhibition in 9/10 of the strains tested with the most impressive activity being recorded on MSSA, A. niger and Penicillium sp. with a minimum inhibitory concentration of 1 μg/mL however this strain did not show inhibition of E. coli. The survey of fermentation conditions revealed the crude extract exhibited the best antimicrobial activity on medium P at pH 7.2, temperature 37 oC. The two segments No. 2 and No. 3 (Rf = 0.23 and Rf = 0.28) contain compounds that were active on A. niger.