| Summary: | 碩士 === 國立海洋大學 === 水產食品科學系 === 85 === Bacteriocin was produced by Pediococcus pentosaceus ACCEL. It
was extracted from its producer and Listeria monocytogenes CCRC
14845. The adsorption of crude bacteriocin was high at pH 6, and
low at pH 2. The optimal adsorption was 30~40-folds and 50-folds
of cell volume, respectively. The recovery was 100% and 50%, and
specific activity increased as much as to 495-fold and 219-fold.
The extracted bacteriocin was characterized as a strong
hydrophobic cation by cation exchange HPLC. Gel filtration and
SDS-PAGE showed only one single band that highly purified
bacteriocin was extracted from cell-adsorption-desorption
method. The results of SDS, non-denature-PAGE, and gel
filtration, showed that Accel aggregated together in native
form.Bacteriocin Accel was inactivated by alfa-amylase. The SDS-
PAGE gel band was stained by periodic acid-Schiff reagent. The
molecular weight was 3,300 to 3,500 Da during SDS-PAGE and gel
filtration analysis. Bacteriocin Accel is a small glycopeptide.
The amino acid sequence was identified as N-Lys-?-Gly-?-Asn-Trp-
Val-Trp. There were two unusual amino acid constituents in the
first of eight amino acids.Bacteriocin Accel possessed
antibacterial activity at pH 2~10 and it was heat-stable (100℃,
60 min) at low pH. It was susceptible to enzyme such as pronase,
chymotrypsin, and pepsin. Accel had broad antibacterial
spectrum, not only against L. monocytogenes, but also against
some other of G (+) and G (-) bacteria strains.The inactivation
of Listeria monocytogenes CCRC 14845 by Accel was more sensitive
at log phase than it was at stationary phase. The bacterocide
action did not induce cell lysis. The purified bacteriocin
solution and its freezing-dried powder with different pH were
stored at 4, 15, 25 and 35℃ in 30 days. The results showed that
the activity of bacteriocin solution decreased significantly
with the increase of temperature and pH. The activity of
bacteriocin powder, however, remained unchanged during storage.
The activity of the powder was more stable than that of the
solution.
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