Isolation, Characterization and Identification of Agarase-Producing Marine Bacteria

Abstract

This study aimed to isolate, characterize and identify agarase-producing marine bacteria from a seaweed farm in Calatagan, Batangas. Several samples, such as seawater, sediment, sea urchin, starfish, sea cucumber and seaweed, were collected. Serial dilutions of these samples were plated into Marine Agar (MA) plates and screened for agarolytic activities through the presence of “depression forming units” (DFUs) that indicated agarase production. Agarolytic activities were consistent from the isolates obtained from the sea urchin Echinotnx calamaris, as such, these isolates were chosen for further characterization. DNA was extracted from two isolates from sea urchin Echinotrix calamaris (SU1-4 and SU1-6) using Xanthogenate-SDS Method and the PureGene DNA Extraction Kit (Gentra). No DNA was successfully extracted from SU1-4 while DNA was successfully extracted from SU1-6. The 16S rDNA of SU1-6 was PCR-amplified and sent to the Davis Sequencing Facility in the United States for sequencing. Sequence analysis of the partial forward sequence using BLAST showed that SU1-6 is closely matched to Photobacterium sp. HAR72. Phylogenetic tree construction using molecular softwares (ClustalX 1.8, BioEdit and Mega 3.0) showed that SU1-6 is closely related to the genera Photobacterium.