Electronic Theses and Dissertation

Ikan naleh (Barbonymus sp.) merupakan salah satu spesies ikan air tawar endemik dari wilayah barat dan selatan Provinsi Aceh yang memiliki potensi sebagai sumber probiotik alami. Penelitian ini bertujuan untuk mengisolasi dan mengkarakterisasi Bakteri Asam Laktat (BAL) dari saluran pencernaan ikan naleh, serta melihat potensi aktivitas antibakteri terhadap Pseudomonas fluorescens ATCC-17550. Metode yang digunakan meliputi isolasi menggunakan media selektif MRSA yang ditambah dengan 1% CaCO3 dan karakterisasi BAL meliputi pengamatan morfologi makroskopis koloni dan mikroskopis sel bakteri (pewarnaan Gram dan pewarnaan endospora), uji biokimia seperti TSIA, SIM, dan MR-VP, serta uji antibakteri terhadap Pseudomonas fluorescens. Dalam penelitian ini berhasil diisolasi sebanyak 19 isolat BAL (NB2 1, NB2 2, NB2 3, NB2 4, NB2 6, NB2 7, NB2 8, NB2 10, NB2 11, NB2 12, NB2 13, NB2 14, NB2 15, NB2 19, NB2 20, NB2 21, NB2 22, NB2 23, NB2 24). Karakteristik makroskopis isolat BAL dari saluran pencernaan ikan naleh meliputi warna koloni putih (74%), krem (21%) dan kuning (5%), bentuk bulat (100%), tepian licin (100%), elevasi cembung (63%) dan timbul (37%), serta ukuran koloni kecil (95%) dan sedang (5%). Seluruh isolat BAL termasuk Gram positif (100%) dengan bentuk isolat kokus (95%) dan basil (5%), serta tidak membentuk endospora. Hasil uji TSIA menunjukkan fermentasi homofermentatif, hasil negatif pada uji indol dan VP, dan hasil positif pada uji MR. Aktivitas antibakteri diuji dengan metode difusi cakram terhadap Pseudomonas fluorescens, isolat NB2 1, NB2 2, NB2 3, NB2 4, NB2 6, NB2 8, NB2 10, NB2 11, NB2 12, NB2 13, NB2 14, NB2 19, NB2 21, NB2 23 dan NB2 24 menunjukkan daya hambat tergolong lemah (

Barbonymus sp., commonly known as "ikan naleh", is a freshwater fish species endemic to the western and southern regions of Aceh Province, Indonesia, with promising potential as a natural probiotic source. This study aimed to isolate and characterize Lactic Acid Bacteria (LAB) from the intestinal tract of Barbonymus sp. and to evaluate their antibacterial activity against Pseudomonas fluorescens ATCC-17550. LAB isolation was conducted using de Man, Rogosa, and Sharpe agar (MRSA) supplemented with 1% CaCO₃. A total of 19 LAB isolates (designated NB2 1 through NB2 24, excluding non-viable isolates) were obtained for further characterization. Morphological characterization included both macroscopic colony observation and microscopic cell analysis, involving Gram staining and endospore staining. Biochemical profiling was conducted using TSIA, SIM, and MR-VP tests. Antibacterial activity was assessed using the disc diffusion method. Most isolates produced white (74%), cream (21%), or yellow (5%) colonies with round shape (100%), smooth edges (100%), convex (63%) or raised (37%) elevation, and small (95%) or medium (5%) colony size. All isolates were Gram-positive, with coccus morphology dominating (95%) and non-spore-forming traits. Biochemical results indicated homofermentative metabolism (TSIA), negative results for indole and Voges-Proskauer tests, and positive methyl red test. Antibacterial assays revealed that most isolates showed weak inhibition zones (