Abstract: A lactic acid bacterial strain with broad-spectrum and obvious antibacterial activity, named as LPb1 was selected from soybean cheese by agar diffusion method. Based on 16S rDNA sequence alignment and physiological and biochemical analysis, the isolated strain was identified as Lactobacillus plantarum. The inhibitory activity of strain LPb1 fermentation supernatant was not affected by high temperature, 1% TritonX-100, Tween-80, Tween-20, SDS, EDTA, or low pH (pH <5). However, its inhibitory activity revealed an obvious decrease after treatment with protease K and trypsin. Moreover, the fermentation supernatant of LPb1 strain could inhibit both some gram-positive bacteria and partial gram-negative bacteria. In contrast, the fermentation supernatant of LPb1 strain did not reveal inhibitory effect against yeast or mould.

Key words: lactic acid bacteria, screening, inhibitory activity