Isolation and Identification of Halophilic Bacteria Isolated from Mangrove Soil in Blue Lagoon, Port Dickson, Negeri Sembilan

Halophiles bacteria are capable of tolerating and surviving in extreme salinity due to the special biological structure that it possesses. Classification of halophilic bacteria includes slight, moderate, and extreme halophiles which range from low to high concentrations of salt. Biotechnological products yielded from bacteria residing in saline environment are proven to be valuable in a few industries. The isolated halophilic bacteria may yield powerful biomolecules such as enzymes which can enhance plant development, hence boosting agricultural industries. However, the insufficient data related to halophiles available in Malaysia may reduce the potential use of these bacteria in related industries. The goal of this study is to isolate and identify the potential halophilic bacteria and to determine the tolerance of halophiles in different concentrations of salt. Collection of soil samples was done at the mangrove soil in Blue Lagoon, Port Dickson, Negeri Sembilan. Isolation and purification of halophiles was done on nutrient agar media supplemented with 3% salt. Next, Gram-staining was performed on 4 colonies of bacteria with different types of single colony appearances. Then, the selected bacteria with different colony and morphological characteristics were tested in nutrient broth supplemented with 0%, 3%, 10% and 20% of salt. Molecular identification was conducted which involved DNA extraction and Polymerase Chain Reaction. All 4 isolates selected were tested to be Gram-stain positive and possessed rod-shaped. The bacteria have various salinity tolerance levels which may be due to the presence of different enzymes produced in their cells. Gene sequences and phylogenetic tree were analyzed based on 16s rRNA sequences to identify the species of the isolates. At the end of the experiment, isolate 2A1 and 2A4 were identified as Bacillus sp., while isolate 2A2 and 2A3 were identified as Cytobacillus oceanisediminis.