Fatty acid profile and fuel-derived physico-chemical properties of biodiesel obtained from an indigenous green microalga, Desmodesmus sp. (I-AU1), as potential source of renewable lipid and high quality biodiesel

Abstract

Organic sources of biodiesel such as microalgae are considered as potential renewable energy resources. These organisms are considered as sunlight-driven cellular factories that convert carbon dioxide to high amounts of lipids that can be used for biofuel production. This paper describes the possibility of using Desmodesmus sp. (I-AU1) for biodiesel production by evaluating its fatty acid profile distribution pattern and estimating the fuel-derived physical and chemical properties from fatty acid methyl esters (FAMEs) obtained from the trans-esterified microalgal oil. Growth rate, oil content, biomass, and lipid productivity of the algal strain have been investigated under nitrogen-starved (0.375 g L−1 NaNO3 in BG 11 medium) autotrophic condition for 22 days. Maximum average biomass yield of Desmodesmus sp. (I-AU1) is 0.745 g L−1 having 36.14% lipid content per dry weight of biomass, with a specific growth rate of 0.20 day−1. Fatty acid profiling of the biodiesel obtained from Desmodesmus sp. (I-AU1) contained total saturated fatty acid (SAFA) methyl esters of 31.02%, while the total monounsaturated fatty acid (MUFA) (C18:1) is 25.64%. Percentage composition of SAFA and MUFA for the microalga was 56.66%, which is high compared to that of most of related studies. Fuel properties were determined by empirical equations and were found to be within the limits of biodiesel standards ASTM D6751 (American) and EN 14214 (European). The quality properties of the biodiesel were low density (0.88 g cm−3), low kinematic viscosity (2.81 mm2 s−1), cetane number (43.47), oxidation stability (5.96 h), and cold filter plugging point (−7.41 °C). Hence, Desmodesmus sp. (I-AU1) has potential as a feedstock for the production of quality biodiesel.