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Bacilli are widely used as functional probiotics, feed and food additives. In this work, Bacillus sp. LS 1-2, was isolated from Korean transitional soybean paste foods and had similar 16S rRNA of Bacillus sp. about 98%. LS 1-2 was cultured in citrus-processing-waste containing 5%
solid as a culture medium and produced an antimicrobial agent against both of the gram-positives and negatives at optimal culture conditions (pH, Temperature, Culture period, etc). An antimicrobial agent produced by LS 1-2 was purified by alcohol precipitation, C-18 cartridge, YM-10, silica gel open column, prep TLC and prep HPLC. The antimicrobial activity was detected in the fermentation supernatant of LS 1-2. The active substance exhibited more activity through the each purification step. The molecular weight of an antimicrobial agent was found to be lower than 10,000Da, and was a hydrophilic compound. The active substance was not sensitive to lipase, proteinase K, amylase, catalase but was affected by pronase E. Thus this antimicrobial agent was expected to be a bacteriocin-like-substance. In order to evaluate its commercial
value, the minimum inhibitory concentration of, the purified antimicrobial agent from Bacillus sp. LS 1-2 was compared with commercialized antimicrobial agents (Colistin, Chlortetracycline, Ampicillin) against Staphylococcus aureus and Escherichia coli O-157.