Tropical marine Navicula salinicola NBO: Morphology, genetic identification, and biochemical properties

Abstract

Indonesia's oceans are rich in microalgae as unicellular photosynthetic organisms. So far, most of Indonesia's diverse microalgae have yet been explored. An Isolate NBO of microalgae has been collected from Bokor Island in the Jakarta Bay, Indonesia. This study aimed to identify the isolate NBO and to characterize its biochemical properties. The identification was carried out based on the physical morphology of cell and the nucleotide sequence of 18S rDNA-V4 and LSU D2/D3 DNA regions, meanwhile, the biochemical properties were characterized based on the content of carbohydrate, lipid and fatty acid of cells. The results showed that the morphological characteristics of NBO cells possessing a color of pale yellow, an oval shape ranging from 11.00-15.00 μm in length and 4.67-5.00 μm in width, and a silica frustule that bilaterally symmetrical oval closed to genus Navicula. Based on the homology of sequences 402-bp of 18S rDNA-V4 and 591-bp of LSU D2/D3, the isolate was identified as Navicula salinicola. Total carbohydrate and lipid contents of Navicula salinicola NBO were 13.13 and 3.74% (w/w), respectively. Fatty acids of Navicula salinicola NBO were dominated by palmitic acid (C16:0), palmitoleic acid (C16:1), and eicosapentaenoic acid (EPA; C20:5) with a total concentration of 38.24, 37.23, and 12.54% (w/w, fatty acid/lipids), respectively, indicating a promising candidate for biodiesel and nutrition/ pharmaceutical.