Molecular characterization of blue-green algae (Anabaena constricta) and comparative studies of biodiesel production from other species

Abstract

Biodiesel can substitute fossil fuels adequately and thus, considered ‘future fuel’. Thus, identifying a promising algal strain for efficient biodiesel production is a very important endeavor. In the present investigation, the blue green algae, Anabaena constricta could be grown aseptically attaining exponential phase, 3 days post inoculation, responds to phototropism and amenable to both autotrophic and heterotrophic mode. Phylogenetic analysis reveal that Anabaena constricta grouped separately from other algal strains used in the study, making it unique in nature. Further, comparative studies of selected algal and blue green algal strains based on the oil percentage and fatty acid profile indicate potential biodiesel properties. The total lipid content of Anabaena constricta is estimated to 14% of the dry weight, and fatty acids profiling indicate presence of 11 fatty acid methyl esters (FAMEs), principally palmitic acid (16:0), oleic acids (18:1), linoleic acid (18:2), palmitoleic acid (16:1). The algal species, Hydrodictyon registered highest percentage of unsaturated fatty acids (59.5%), while highest content of saturated fatty acid was found in Anabaena constricta (51.5%). Cetane Number of seven algal and blue green algal biodiesel varied from 54.77 to 58.2 and Saponification Value varied from 205.6 to 211.39. PROMETHEE & GAIA analyses indicate both the Rhizoclonium and Tolypothrix species outranked while Hydrodictyon and Anabaena constricta are the least suitable species in seven algal and blue-green algal species studied for biodiesel production. Well-characterized strains offer promise for biodiesel production at a cost-effective level. The present study focus on the renewable fuel, which is useful for reducing the carbon footprint with potential to impact self-sustainability in fuel sector, without modification in current infrastructure.