Abstract

Nisin is the most well-known representative of subtype A1 lantibiotics. This small (< 5 kDa) peptide ribosomally produced by Gram-positive bacteria belonging to Lactococcus, Streptococcus, Staphylococcus and Blautia species. Nisin exhibits antibacterial activity against a broad range of Gram-positive bacteria and may be effective against Gram-negative pathogens. For analytical semi-preparative purposes, gradient HPLC is often used in the acetonitrile concentration range from 20 to 30 % (solvent B) and a retention time of 20 to 50 min. In this study the optimal conditions for the analysis of nisin by RP-HPLC were determined: a gradient from 23 to 28 % acetonitrile (buffer B) when used as solvents: buffer A: [4 M LiClO₄ – 0.1 M HClO₄ ] : H₂O=1:19; and buffer B: 100 % CH₃CN with a retention time up to 12 min. Differences between the chromatographic profiles of expired and non-expired nisin samples have been identified. The expired nisin sample differs from the non-expired samples by the presence of asymmetric nisin A / Z peaks with significant degradation of the nisin A peak. The results of the study indicate the possibility using RP-HPLC for checking the quality and shelf life of commercial nisin samples without the need for additional purification

Keywords: reverse-phase high performance liquid chromatography (RP-HPLC), bacteriocins, nisin, expired and non-expired nisin samples

Article language: En