Abstract: CF10, a strain producing inhibitory activity substance, screened out by scrip method and cylinder-dish method from the by product yellow-liquor, was identified as Lactobacillus buchneri. The supernatant of CF10 culture exhibited strong inhibitorya ctivitya gainstt heg ram-positiveb acteria,i ncludingS taphylococcusa ureusa ndB acillus subtilis, andr esistedi nterfering effects of organic acids and hydrogen peroxide. A strong inhibitory activity was also observed against the gram-negative bacteria, such as Escherichia coli and Pseudomonas pyocyanea, Saccharomyces cerevisiae K and some epiphyte. CF10 was complexly mutated by ultraviolet radiation(UV) and diethyl sulphate(DES). The relative protency of supernatant thus increased 258% with stable inheritance. The culture medium composed of maltose as carbon source and peptone and yeast extract asnitrogen source would enhance, the maximum inhibitory activity of the mutant bacteriocinoid under the optimal conditions: culture temperature 37℃, initial pH6.0～6.5 for 48h, 1% inoculation, in anaerobic condition, and presence of K+、Mg2+ and Mn2+.

Key words: Lactobacillus buchneri； bacteriocin-like substance； mutation； , fermentative conditions； bio-characteristics；