Abstract:
Bacteriocins are antimicrobial peptides produced by diverse bacterial species that inhibit or
kill other microorganisms. In the food industry bacteriocins have potential application as
preservative. The bacteriocin obtained from fermented broth in a crude form that may contain
lactic acid, acetic acid, H2O2 and other antimicrobial substances. Therefore, the objectives of
the study were to purify the bacteriocin and to reveal the possibility of purified compound
as biopreservative. Crude bacteriocin was produced
by Lactobacillus reuteri AF182723 isolated from traditionally prepared curd in liquid fermentation
system. When the crude bacteriocin was purified by sequential three step procedure involving
ammonium sulfate fractional precipitation, cation exchange (SP Sepharose) chromatography
and size exclusion (Sephadex G-100 column) chromatography, the specific activity (AU/mg)
of the bacteriocin increased in each step of purification and it reached 6349.2AU/mg finally
from 262.3 AU/mg with the purification fold of 24.206. When the purified bacteriocin was
subjected to different temperature and pH treatments, it found stable over wide temperature
range (45ºC - 75ºC) and pH range (3-7). When exposed to different enzymes, the purified
bacteriocin showed resistant to catalase and amylase enzymes, but showed significantly
higher sensitive to pepsin and proteinase K indicating that the antimicrobial substance was
proteinaceous in nature. This study concluded that bacteriocin produced
by Lactobacillus reuteri AF182723 could be used as a potential food biopreservative. Further
safety studies should be done to recommend this potential bacteriocin as
food biopreservative.
