Purification and Characterization of Antimicrobial Peptide from an Epilithic Bacterium Streptomyces sp. AL50 with Activity Against Biofilm Forming Coagulase-Negative Staphylococci

Abstract

Antimicrobial peptide (AMP) is increasingly recognized as a promising new avenue in addressing the challenge of antibiotic resistance, offering a notable alternative to traditional antibiotic molecules. The current research focuses on extracting and characterizing AMP named as AMP1 from epilithic bacterial isolate Streptomyces sp. AL50, an area that has so far remained underexplored. The AMP1 was purified by ammonium sulfate precipitation, dialysis, and sephadex G-100 column chromatography. Subsequent analysis using Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed major band with molecular mass of approximately 10.83 kDa. The peptide demonstrated potent activity against Staphylococcus epidermis MTCC3615, with MIC value of 4 μg/mL. Remarkably, the peptide retained its activity up to 70 °C temperature and within a pH range of 6.0-8.0. However, its activity was abolished by proteinase K, trypsin, and papain, while pepsin, lipase, and α-amylase had no effect. Furthermore, AMP1 displayed notable capabilities in inhibiting and eradicating biofilms. These results indicate that AMP1 hold significant potential as antibiotic candidates for treating multidrug-resistant bacterial infections.