Bioactivity of purified nisin (WT) and nisin K12A against representative Gram-negative targets.

Results from agarose gel diffusion assays of purified nisin and nisin K12A at a concentration of 40 µM against three Gram-negative strains. Results are expressed as both zone diameter and as K12A bioactivity compared to that of nisin A at 100%. Values represent the mean of triplicate agarose assay results. Standard deviation values in brackets; Relative Standard Deviation<10% for each given value. Values in bold reached statistical significance compared to nisin control (Student's t-test: P<3E−04).