Isolation of Antibiotic-Producing Bacteria from Extreme Microhabitates in Mangrove Ecosystem

Abstract

This study aims to isolate and identify the antibiotic-producing bacteria from extreme microhabitates in the marine ecosystem against fish pathogenic bacteria (V. alginolyticus, A. hydrophila, dan Pseudomonas sp). Microbes from samples were grown on NA and TSA media. Well grown colonies were examined for their ability to produce antibiotics against the pathogens by the streaking and paperdisc diffusion method on MHA. Potential isolates were identified through a series of phenotypic and genotypic test. A number of 4 antibiotic-producing bacteria were selected. DNA of the bacteria were extracted using DNA easy mini column and amplified by using Kappa PCR kit with 16S rDNA 1A and 16S rDNA2A primers. The PCR results were analyzed on a 1.5% agarose gel in Tris-acetat-EDTA (TAE) electrophoresisuffer (4 mM Tris-acetate and 1 mM disodium EDTA at pH 8.0). The electrophoresis process was carried out at 60 mA (100-120 v) for 30-45 minutes read by UV Transilluminator. Isolate Ni5 have a 99% homological similarity to Bacillus amyloliquefaciens strain SH20. Bacterial isolate Xy3 has a 100% homological similarity with Bacillus cereus strain NY180. Isolate S11 has a 97% homological similarity with Enterobacter hormaechei strain CGAPGPBBS-064. Isolate K22 has a 99% homological resemblance to Klebsiella pneumoniae strain MW-W 754.