ISOLATION OF A NOVEL ANTIMICROBIAL POLYPEPTIDE FROM AN Aspergillus niger ISOLATE

Abstract

In this study the extracellular proteins from the isolate LC3 belonging to Aspergillus were purified for new antimicrobial polypeptide (AMP) discovery and then tested for antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Methicillin-resistant S. aureus (MRSA). Antimicrobial activity was determined by the trypsin/proteinase K assay, which was polypeptide-based, and it was observed that this protein was a protein of about 11 kDa by gel overlay assay. The minimum inhibitory concentration of purified AMP molecule against S. aureus ATCC 25923 and MRSA was 8 µg/ml and 32 µg/ml, respectively and the AMP molecule was confirmed. ITS sequence analysis showed that isolate LC3 was identified as Aspergillus niger, using the Bioedit sequence assembly program. The sequence was deposited with the GenBank database with accession number MK332597. The results indicate that the purified AMP molecule has the potential to be used in infections caused by S. aureus.