Mass cultivation of microalgae and extraction of total hydrocarbons: A kinetic and thermodynamic study

In this present investigation, the biofuel alga Botryococcus braunii (B. braunii) was mass cultivated in 10 m(2) open raceway pond at batch mode. This study was mainly focused on the kinetics and thermodynamics approach for total lipid and hydrocarbon extraction. At batch mode cultivation the alga produced highest dry biomass of 23 g m(-2) d(-1). The algal cells were harvested by autoflocculation method and dried. Different pre-treatment methods, solvents systems and optimization of extraction parameters were carried out in the dry biomass containing moisture less than 1 wt%. This reveals ultrasonication combined with chloroform: methanol, extracted maximum of 24.2 wt% total lipid and hydrocarbon. Temperature effects (308-338 K) on kinetics were investigated. The extraction follows first order kinetics and their rate constants and activation energy were determined as 3.0431 s(-1)and 36.7214 kJ mol(-1) respectively. Thermodynamic activation parameters Delta G(not equal), Delta H-not equal and Delta S-not equal were measured, which suggest that the process was endothermic, irreversible and spontaneous. (C) 2013 Elsevier Ltd. All rights reserved.