Evaluation of Chlorella sorokiniana cultivated in outdoor photobioreactors for biodiesel production

Abstract

Microalgae strains that present high growth rates and accumulate protein and lipid at high yields and productivities have the potential to be utilized for food and biodiesel production. In the present work, Chlorella sorokiniana CTT 7727 was evaluated in terms of growth parameters and biomass compositions, presenting promising characteristics to be cultivated in large scale outdoor photobioreactors. The strain presented a biomass productivity of 0.0433 g L⁻¹day⁻¹, lipid productivity of 0.0083 g L⁻¹day⁻¹, lipid content of 20.08%, protein content of 50.44% and carbohydrate content 16.20%, beyond a maximum specific growth rate of 0.250 day⁻¹. Harvesting with ferric chloride at 0.75 g L⁻¹ recovered biomass with minimal loses. The fatty acids methyl esters (FAME) profile exhibited C16:0 (39.68%), C16:1 (7.22%), C18:0 (5.49%), C18:1 (17.20%), C18:2 (15.97%) and C18:3 (11.03%). The biodiesel properties predicted with this FAME composition revealed 54.09 of cetane number, 81.95 g I₂ 100 g⁻¹ of iodine value, 9.57 °C of cold filter plugging point, 15.88 °C of cloud point and 39.18 MJ kg⁻¹ higher heating value. These properties indicated a potential to be used as B100 in tropical countries and mixture in cold weather countries.

Keywords:

• Microalgae
• growth parameters
• biomass compositions
• FAME
• characterization
• lipids

Disclosure statement

The authors declare no conflict of interest.