SELEKSI, OPTIMASI DAN KARAKTERISASI BAKTERIOSIN YANG DIPRODUKSI BAKTERI Bacillus DARI SALURAN PENCERNAAN AYAM KAMPUNG (Gallus domesticus)

VIKO AZI CAHYA, Dr. Ir. Chusnul Hanim, M.Si., IPM.; Prof. Dr. Ir. Lies Mira Yusiati, SU., IPU.

2019 | Tesis | MAGISTER ILMU PETERNAKAN

Penelitian ini bertujuan untuk melakukan isolasi, optimasi dan karakterisasi bakteriosin yang diproduksi bakteri Bacillus dari saluran pencernaan ayam kampung (Gallus domesticus). Penelitian ini terbagi dalam tiga tahap. Tahap pertama yaitu isolasi, seleksi dan identifikasi bakteri Bacillus. Tahap kedua yaitu optimasi produksi biomasa sel Bacillus menggunakan kondisi pH medium (5; 5,5; 6; 6,5; 7; 7,5; 8; 8,5) dan suhu inkubasi berbeda (31, 33, 35, 37, 39, 41 derajat Celcius). Tahap ketiga yaitu karakterisasi bakteriosin. Data isolasi, seleksi, identifikasi bakteri dan berat molekul dianalisis menggunakan analisis deskriptif. Data optimasi produksi dan pengujian stabilitas bakteriosin dianalisis menggunakan one-way analysis of variance (ANOVA), kemudian bila terdapat perbedaan yang nyata besarnya variabel karena perlakuan, dilanjutkan dengan uji Duncan's New Multiple Range Test (DMRT). Seleksi isolat bakteri Bacillus unggul dilakukan dengan menguji daya hambat isolat terhadap patogen Escherichia coli. Berdasarkan hasil seleksi diperoleh tiga isolat unggul yang menghasilkan luasan zona bening paling tinggi, yaitu isolat 2, 3B dan 11A (23,7; 18,6 dan 19,9 mm). Ketiga isolat diidentifikasi secara biokimiawi dan diperoleh hasil bahwa ketiga isolat merupakan jenis bakteri Bacillus, Gram positif, menghasilkan spora dan katalase positif. Berdasarkan hasil optimasi produksi biomasa yang dilakukan, suhu dan pH terbaik untuk produksi biomasa sel bakteri Bacillus 11A adalah pada pH 6,5 dan suhu 39 derajat Celcius. Bakteriosin mulai diproduksi pada akhir fase log atau awal fase stasioner. Bakteriosin yang diproduksi Bacillus subtilis 11A memiliki spektrum luas terhadap patogen Gram positif (Staphylococcus aureus) dan Gram negatif (Escherichia coli dan Salmonella typhimurium). Karakteristik bakteriosin yang diproduksi Bacillus subtilis 11A yaitu, spektrum luas, termostabil hingga suhu 90 derajat Celcius, stabil pH 6 sampai 9, berat molekul 21,45 kDa dan mampu bertahan hingga lama penyimpanan 28 hari pada refrigerator. Berdasarkan hasil yang diperoleh, dapat diambil kesimpulan bahwa bakteri Bacillus pada saluran pencernaan ayam kampung menghasilkan bakteriosin yang memiliki aktivitas antimikrobia.

This research aimed to isolate, to optimize and to characterize bacteriocin produced by Bacillus bacteria from digestive intestinal tract of native chicken (Gallus domesticus). This research was divided into three steps. The first step was to isolate, to select and to identify potential superior Bacillus bacteria. Second step was to optimize the biomass cell production of Bacillus bacteria using different pH medium conditions (5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5) and different incubation temperatures (31, 33, 35, 37, 39, 41 degree Celcius). Third steps was to characterize the bacteriocin produced by Bacillus bacteria. The data of isolation, selection, identification of Bacillus bacteria and molecular weight of bacteriocin was analyzed descriptively. The data of biomass cell production and the stability of bacteriocin on pH, temperature and storaging time were analyzed by one-way analysis of variance (ANOVA), if there was significant value, test followed by Duncan's New Multiple Range Test (DMRT). Selection of Bacillus bacterial isolate was carried out by inhibitory activity assay of all isolates against pathogen Escherichia coli. Based on the results of the selection, three isolates were obtained which produced the highest clear zone (isolate 2, 3B and 11A (23.7; 18.6 and 19.9 mm)). The three isolates were identified biochemically and the results showed that the three isolates were Bacillus bacteria, Gram positive, produced spores and catalase positive. Based on the results of biomass cell production optimization, best temperature and pH for the biomass cell production of Bacillus subtilis 11A was at pH 6.5 and temperature 39 degree Celcius. Bacteriocin was produced at the end of the log phase or at the beginning of the stationary phase. Bacteriocin produced by Bacillus subtilis 11A had a broad spectrum against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli and Salmonella typhimurium). The characteristics of bacteriocin produced by Bacillus subtilis 11A were broad spectrum, thermostable temperature up to 90 degree Celcius, stable pH 6 up to 9, molecular weight of 21.45 kDa and could last up to 28 days long storage in the refrigerator. Based on the results obtained, it could be concluded that Bacillus bacteria in the digestive tract of native chickens produced bacteriocin which had antimicrobial activity.

Kata Kunci : Bacillus, Bakteriosin, Isolasi, Karakterisasi, Optimasi biomasa sel