Isolation and Identification of Bacteriocin-producing Bacillus Strain Isolated from the Gastrointestinal Tract of Indonesian Native Chicken (Gallus domesticus)

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.