Abstract:

A lactic acid bacterial strain, Lactobacillus HLJ-174, was isolated from naturally fermented Chinese sauerkraut
from Heilongjiang province. The bacteriocin produced by it showed a strong antibacterial activity against Escherichia
coli, Pseudomonas fluorescens, Bacillus cereus and Micrococcus aureus after elimination of some interference factors
such as organic acid and hydrogen peroxide. Based on morphological, physiological and biochemical characteristics and
16S rDNA sequence analysis, the strain HLJ-174 was identified as Lactobacillus plantarum. The bacteriocin from HLJ-174
was extracted with organic solvent, and higher extraction efficiency was obtained using butanol and ethyl acetate, but it was
not extractable with other organic solvents such as hexane, methylene chloride, chloroform, carbon tetrachloride, acetone
and ethanol. Furthermore, the addition of different volumes (0.5-, 1.0-, 1.5-, 2.0-, 2.5- and 3.0-fold) of butanol or ethyl
acetate to the fermentation broth was applied to extract the bacteriocin, and the results showed that the best extraction
efficiency was achieved by using 1.5-fold volume of butanol as the extraction solvent. The extract was further
purified by Sephadex LH-20 chromatography, and the purified product exhibited a strong antibacterial activity against
Escherichia coli and Bacillus cereus.

Key words: Lactobacillus, bacteriocin, strain identification, extraction