Electronic Theses and Dissertation

Bakteri asam laktat (bal) merupakan kelompok bakteri gram positif yang tidak menghasilkan spora, berbentuk basil atau kokus dan dapat memproduksi asam laktat. keberadaan bal dalam saluran pencernaan tiram menghasilkan berbagai senyawa metabolit yang dapat berperan sebagai antibakteri. penelitian ini bertujuan untuk mengisolasi, mengkarakterisasi dan mendapatkan jumlah isolat bal dari saluran pencernaan tiram budidaya dan non budidaya, serta menganalisis potensi bal yang memiliki aktivitas antibakteri dari saluran pencernaan tiram pasifik (crassostrea gigas). metode penelitian yang digunakan untuk menguji aktivitas antibakteri adalah metode difusi cakram. hasil penelitian diperoleh sebanyak tiga isolat asal tiram budidaya (tb2c1, tb2c2, tb3c1) dan tiga isolat asal tiram non budidaya (tn1c2, tn1c3, dan tn3c1). hasil karakterisasi isolat berdasarkan ciri morfologi koloni adalah berwarna putih dan putih susu, berbentuk bundar, tepian licin dan berombak, elevasi datar, cembung dan timbul. sedangkan ciri morfologi sel berbentuk kokus. semua isolat bal mampu menghambat pertumbuhan bakteri staphylococcus aureus dan escherichia coli. zona hambat terbesar terdapat pada isolat bakteri tn1c3 sebesar 3,50 ± 0,51 dan zona hambat terkecil pada isolat tn1c2 sebesar 0,98 ± 0,05. kata kunci : bakteri asam laktat (bal), saluran pencernaan tiram, aktivitas antibakteri, staphylococcus aureus dan escherichia coli.

Lactic acid bacteria (LAB) are a group of Gram-positive bacteria that do not produce spores, are in the form of bacilli or cocci and can produce lactic acid. The presence of LAB in the oyster digestive tract produces various metabolite compounds which can act as antibacterials. This study aims to isolate, characterize and obtain the number of LAB isolates from the digestive tract of cultivated and non-cultivated oysters, as well as analyzing the potential of LAB which has antibacterial activity from the digestive tract of pacific oysters (Crassostrea gigas). The research method used to test antibacterial activity is the disc diffusion method. The research results obtained three isolates from cultivated oysters (TB2C1, TB3C1, TB3C2) and three isolates from noncultivated oysters (TN1C2, TN1C3, and TN3C1). The results of the characterization of the isolates based on the morphological characteristics of the colonies were white and milky white in color, round in shape, smooth and wavy edges , flat, convex and raised elevations. Meanwhile, the morphological characteristics of the cells are cocci-shaped. All LAB isolates were able to inhibit the growth of Staphylococcus aureus and Escherichia coli bacteria. The largest zone of inhibition was found in the TN1C3 bacterial isolate at 3,50 ± 0,51 and the smallest zone of inhibition was in the TN1C2 isolate at 0,98 ± 0,05. Key words: Lactic acid bacteria (LAB), digestive tract of oyster, antibacterial activity, Staphylococcus aureus and Escherichia coli