Detection of nisin expression by Lactococcus lactis using two susceptible bacteria to associate the effects of nisin with EDTA.
Nisin, a bacteriocin produced during the exponential growth phase of Lactococcus lactis ATCC 11454, inhibits the growth of a broad range of Gram-positive bacteria. Gram-negative bacteria can also be inhibited by nisin with EDTA. In this study, nisin production was assayed by the agar diffusion method using Lactobacillus sake ATCC 15521 and a recombinant Escherichia coli DH5-alpha expressing the recombinant green fluorescent protein as the nisin-susceptible test organisms. The titers of nisin expressed and released in culture media were quantified and expressed in arbitrary units (AU/mL of medium) and converted to standard nisin concentration (Nisaplin, 25 mg of pure nisin with an activity of 1 x 10(6) AU/mL). The expression and release of nisin by L. lactis in skimmed milk (9.09% total solids) with Man Rugosa Shepeer-Bacto Lactobacilli broth (1:1) was monitored in a 5 L New Brunswick fermentor. Combining EDTA with nisin increased the bactericidal effect of nisin on the bacteria examined. The presence of EDTA was necessary to inhibit E. coli growth with nisin. L. sake was shown to be a good indicator for the evaluation of nisin release in the culture media, including with the addition of EDTA.
Penna
Thereza Christina Vessoni
TC
Department of Pharmaceutical Technology, School of Pharmaceutical Science, University of São Paulo, SP, Brazil. tcvpenna@usp.br
Jozala
Angela Faustino
AF
Gentille
Thomas Rodolfo
TR
Pessoa Júnior
Adalberto
A
Cholewa
Olivia
O
D001681:Biological Assay / Q000379:methods*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004357:Drug Synergism; D004492:Edetic Acid / Q000008:administration & dosage*; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects*; D007778:Lactobacillus / Q000166:cytology / Q000187:drug effects*; D013294:Lactococcus lactis / Q000378:metabolism*; D009561:Nisin / Q000008:administration & dosage* / Q000032:analysis / Q000096:biosynthesis*
D004338:Drug Combinations; D009561:Nisin; D004492:Edetic Acid