Ezea, I.B., Onyeagu, U., Onyia, C.E.
Abstract: Bacteria isolates were obtained from fermented soybean milk and screened for organic acid and antimicrobial substance production. Out of the nine isolates; three designated as ISOA1; ISOA2 and ISOA3 showed a good antimicrobial activity against the target organisms namely; Staphylococcus aureus ATCC 12600; Escherichia coli ATCC 117755; Bacillus cerus; Listeria monocytogens and Escherichia coli 0157 ATCC 438931. This study showed that ISOA1 and ISOA3 were able to tolerate 1.5 pH and salinity upto 5 % w/v. But in case of high temperature tolerance; ISOA2 and ISOA3 tolerate upto 450C. Bacillus cerus and Listeria monocytogens were resistant to ISOA1 and ISOA2 isolates in all dilution factors while they were sensitive to ISOA3 isolate upto 10-2 dilution factor. ISOA1; ISOA2 and ISOA3 were identified as Lactobacillus planetarium; Lactobacillus amylolyticus and Lactobacillus sp and can be use as probiotics.
Keywords: Antimicrobial activity, Environmental tolerance, Soybean, Probiotics and Organic acid