This study aimed to obtain the optimal growth of Bacillus subtilis 11A isolated from Indonesian native chicken (Gallus domesticus). The growth optimization included pH medium conditions (5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5) and different incubation temperatures (31, 33, 35, 37, 39, 41°C). Isolate was incubated for 12 hours using Luria Bertani broth. Optical density was observed using spectrophotometer (λ600) at 0 and 12 hours of incubations. Bacteriocin activity against pathogens Staphylococcus aureus, Salmonella typhimurium and Escherichia coli was determined using a well-diffused method. Data was statistically analyzed using a one-way analysis of variance (ANOVA) followed with Duncan’s New Multiple Range Test (DMRT) to distinguish the treatment means. The results showed that the optimum pH for bacterial growth was at pH 6.5. Optimum temperature for bacterial growth was at 39°C. The highest bacteriocin activity of B. subtilis 11A against indicator pathogens was resulted at stationary phase (1906.14, 2179.79, 2343.07 AU/ml). It can be concluded that B. subtilis 11A isolated from Indonesian native chicken grew optimally for bacteriocin production at pH 6.5 and temperature 39°C. The highest bacteriocin production and activity produced by Bacillus subtilis 11A was at stationary phase.
The purpose of this study was to characterize bacteriocins produced by Bacillus subtilis 11A isolated from Indonesian native chicken's ileum. Characterization of bacteriocins included antimicrobial activity, the stability to temperature, pH, and storage time. Antimicrobial activity was tested against Escherichia coli FNCC 0091 , Salmonella typhimurium FNCC 0134, and Staphylococcus aureus FNCC 0143. Stability to temperature was tested to 4, 30, 70, 80, 90, 100 o C for an hour and 121 o C for 15 min. Stability to pH was tested to pH 2,
This research aimed to obtain Bacillus bacteria from the gastrointestinal tract (GIT) of native Indonesian chicken (Gallus domesticus) for bacteriocin production purposes against Escherichia coli. Bacillus bacteria were isolated from GIT (duodenum, jejunum, and ileum) on Trypticase Soya Agar (TSA+5% NaCl). The dilution was heated at 80°C for 20 min to kill other bacteria and induced Bacillus spore. Screening method based on the ability to against pathogens, then microbiological and biochemical characteristics. Inhibition test against pathogen using a well diffuse method. Thirteen Bacillus isolates then continued for testing against Escherichia coli FNCC 0091 for bacteriocin production purposes. Biochemical identification using conventional identification. The selected Bacillus bacteria, which had the highest inhibition zone, were isolates 2, 3B, and 11A (23.7, 18.6, and 19.9 mm). Biochemical and microbiological identification revealed that the isolate 2 isolated from duodenum was mixed culture (Bacillus subtilis, and Bacillus sp.), isolate 3B isolated from jejunum was mixed culture (Bacillus subtilis, Bacillus sp., and Bacillus sp.) and isolate 11A isolated from ileum was pure culture (Bacillus subtilis). All isolates were identified as rod-shaped, Gram-positive, aerobic, endospore-forming bacteria, and produced catalase.
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