Screening and molecular identification of actinomycetes producing biosurfactant with properties Antimicrobial and biofilm inhibition against pathogenic bacteria

The purpose of the present study was to isolate and identify molecularly native actinobacteria that produce biosurfactant with antimicrobial and anti-biofilm activity against some pathogenic bacteria.

initial screening was done based on oil dispersion test and the best isolate was selected. Ethyl acetate solvent was used for extraction. Antimicrobial and anti-biofilm properties were evaluated using the well diffusion method in agar and 96-well microplate, respectively. FTIR and GC-MS techniques were used for biosurfactant analysis. Finally, the superior isolate was identified using the molecular PCR method.

Biosurfactant of the superior isolate showed the highest and lowest antimicrobial effect at concentrations of 0.4 and 0.3 mg/ml against Pseudomonas aeruginosa and Staphylococcus aureus, respectively. The highest and lowest anti-biofilm effects against Escherichia coli and Pseudomonas aeruginosa bacteria were observed at concentrations of 2 mg/ml. Structural analysis of biosurfactant with FTIR and GC-MS confirmed the structure of amino acid ring with chain of fatty acids and lipopeptide type. The selected isolate was 95% similar to Streptomyces genus and B1AY species.

The local isolate of Streptomyces has a remarkable ability to produce biosurfactant with antimicrobial and anti-biofilm effects against pathogenic bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and can be used in the field of pharmaceutical biotechnology.