Screening and characterization of high lipid accumulating microalga Ankistrodesmus sp. from freshwater environment

ABSTRACT

Microalgae based biofuel is an attractive alternative energy source due to its rapid growth rate and high lipid accumulation efficiency. In this study, we screened high lipid content microalga with the favourable fatty acid composition suitable for biodiesel production. Totally twelve different microalgal species were isolated from freshwater habitats. The isolates were identified as Micractinium sp., Chlorella sorokiniana, Scenedesmus bajacalifornicus, Desmodesmus sp., Scenedesmus obliquus, Coelastrum proboscideum, Chlamydomonas moewusii, Chlamydomonas debaryana, Chlamydomonas dorsoventralis, Coelastrum sp., and Ankistrodesmus sp. based on morphological features and ITS region similarity. Among the isolates, highest lipid content (33±0.07%) and lipid productivity (0.27±0.06 g L-1) were obtained from Ankistrodesmus sp. Intracellular lipid droplets of Ankistrodesmus sp. were observed through Nile red staining. The lipid content was enhanced up to 45% under the nitrogen deficient (5 mg L-1) BG-11 medium. Ankistrodesmus sp. fatty acid profile shows the presence of palmitic (16.39%), stearic (15.67%), oleic (25.66%), linolenic (21.62%), and alpha-linoleic acids (14.34%). The oleic acid was the dominant fatty acid 25.66% in the nitrogen deficient condition.