Growth of Enterococcus mundtii ST15 in medium filtrate and purification of bacteriocin ST15 by cation-exchange chromatography.

摘要

Bacteriocin ST15 (bacST15), produced by Enterococcus mundtii ST15, inhibited the growth of a variety of bacteria, including exopolysaccharide (EPS)-producing strains isolated from biofilms in stainless steel pipes. Maximal production of bacST15 (51200 AU/ml) was recorded after 20 h of growth in MRS broth (Biolab), which was maintained throughout fermentation. Only 12800 AU/ml bacST15 has been recorded in MRS filtrate with components smaller than 8000 Da, suggesting that nutrients larger than 8000 Da are required for optimal bacST15 production. Cation-exchange chromatography yielded an active peptide, which is 3944.00 Da, according to electron-spray mass spectrometry and tricin-SDS PAGE. BacST15 is smaller than the 4287 Da reported for bacteriocins ATO6 and KS produced by E. mundtii . The iso-electric point of bacST15 is between 7 and 9, and similar to that reported for pediocin PD-1.