Purpose:
To carry out the extraction, purification and biological characterization, and assess the
antibacterial activity of bacteriocin from
Lactobacillus acidophilus
XH1.
Methods:
Chloroform extraction method was used for bacterioc
in extraction while characterization of
bacteriocin was carried out by flat-dug well agar diffusion assay. The antibacterial mechanisms of
bacteriocin were examined by scanning electron microscopy and atomic emission spectroscopy. The
molecular weight of l
actobacillin XH1 was measured using Tricine-SDS-PAGE electrophoresis.
Results:
The bacteriocin (lactobacillin XH1) inhibited
Escherichia coli
,
Staphylococcus aureus
and
Bacillus anthracis
. It showed a wide range of antimicrobial activity at pH 1.0-5.0 while at 37
–
120 °C, it
was sensitive to trypsin, pepsin and papain, but insensitive to proteinase K and neutral protease. The
intracellular UV-absorbing substances, namely, lactate dehydrogenase macromolecules, K
+
and ATP of
E. coli, decreased rapidly. The molecular weight of
lactobacillin XH1 was approximately 16 kDa.
Conclusion:
Lactobacillin XH1 is a broad-spectrum antimicrobial substance that is thermostable. Its
antibacterial mechanism on
Escherichia coli is similar to that of bacteriocins on Gram-positive bacteria.
The agent is a hydrophobic protein with more acidic groups.
