(175k) Growth Kinetics and Thermal Characterization of Neochloris Oleoabundans for Biofuel Production

Microalgae cultivation and their use is a promising approach for integrated CO2 biofixation and biodiesel production. For this study freshwater Neochloris oleoabundans was investigated for biomass and lipid productivity in culture media under different CO₂ concentration. This communication also reports thermal characteristics of Nannochloropsis Oculata biomass before and after lipid extraction. 4% CO₂ mixture with air shows promising growth, CO₂ fixation of chlo Neochloris oleoabundans after 15 days of cultivation in wastewater media. The thermal decomposition experiments are conducted in a thermogravimetric analyzer (TGA) using air as combustion agent. The biomass samples are exposed up to 800^oC with different heating rates. The TGA analysis shows that the decomposition profiles of the biomass samples before and after lipid extraction follow different paths. The apparent activation energy of the oxidation reaction is estimated by fitting an iso-conversional model (Kissinger–Akahira-Sunose) with the experimental data. It is observed that at early stage of biomass combustion, the activation energy increase with increasing the conversion until reaching the maximum at almost a middle conversion stage. At a middle conversation stage, there are significant difference, since the maximum reported activation energy is 398 kJ/mol and 219 kJ/mol for biomass and extraction residue respectively. After that the value of activation energy decreases sharply. It is also found that the activation energy of lipid extracted biomass decomposition is significantly lower than that of the biomass sample.

Acknowledgments:

Authors like to acknowledge KACST for funding this work through the project NSTIP 13-WAT96-04.