Isolation, Purification, and Identification of Novel Bacteriocin Produced by Staphylococcus haemolyticus Isolated from Semen Fluid

Background: Bacteriocins, which are ribosomally synthesized peptides, were initially classified as proteinaceous substances that affected the growth and/or viability of closely related organisms. Objectives: The study aimed to obtain an alternative antimicrobial compound, such as bacteriocins isolated from Staphylococcus haemolyticus ( S. haemolyticus ), effective against multidrug-resistant bacteria. Materials and Methods: S. haemolyticus isolates were recovered from 75 semen fluid samples of males aged 18–45 years and identified using macroscopic characteristics. Bacterial identification was confirmed using the Vitek 2 system. The optimization for bacteriocin production was carried out in a modified media with 1% glucose at 37°C for 72 h, with an inoculum size of 1.2 × 10 9 CFU/mL and pH 7. For screening the antibacterial activity of bacteriocin produced by S. haemolyticus , the filter paper disk method was used. Results: Bacteriocin was best produced by S. haemolyticus , and the bacterial activity of the bacteriocin was 70 and 40 AU/mL. After partial purification of bacteriocin by the ammonium sulfate method at saturation, the 70% with Mwt reached 29 kDa. Conclusion: The results of the production and purification of bacteriocin under optimal conditions showed, for the first time, an active local isolate of S. haemolyticus from semen fluid in Iraq.