Assessing biodiesel quality parameters for wastewater grown Chlorella sp.

Microalgae are reported as the efficient source of renewable biodiesel which should be able to meet the global demand of transport fuels. Present study is focused on assessment of wastewater grown indigenous microalga Chlorella sp. for fuel quality parameters. This was successfully grown in secondary treated waste water diluted with tap water (25% dilution) in glass house. The microalga showed a dry weight of 0.849 g L⁻¹ with lipid content of 27.1% on dry weight basis on 21st day of incubation. After transesterification, the yield of fatty acid methyl ester was 80.64% with major fatty acids as palmitic, linoleic, oleic and linolenic. The physical parameters predicted from empirical equations in the biodiesel showed cetane number as 56.5, iodine value of 75.5 g I₂ 100 g⁻¹, high heating value 40.1 MJ kg⁻¹, flash point 135 °C, kinematic viscosity 4.05 mm² s⁻¹ with density of 0.86 g cm³ and cold filter plugging point as 0.7 °C. Fourier transform infra-red (FTIR), ¹H, ¹³C NMR spectrum confirmed the chemical nature of biodiesel. The results indicated that the quality of biodiesel was almost as per the criterion of ASTM standards; hence, wastewater grown Chlorella sp. can be used as a promising strain for biodiesel production.