Chlorella vulgaris as a green biofuel factory: Comparison between biodiesel, biogas and combustible biomass production

摘要

Biofuels are viewed as the answer to safeguard the currently challenged energy security. To this end, the present study provides a comparison between approaches regarding microalgal biomass conversion to bioenergy, with a view on sustainable implementation. The energetic valorization ofChlorella vulgarisbiomass cultivated under heterotrophic, sulfur-limited conditions was investigated through the biofuels biodiesel, biogas (biomethane) and combustible dry biomass. The lipid productivity can reach the value of 442.9?±?6.5?mg?L?1?d?1containing suitable fatty acids for biodiesel production. Next, biochemical methane potential (BMP) assays yielded 360.9?±?20.2?mL?CH4?g?VS?1addedunder mesophilic conditions, while the calorific value of dryC. vulgarisbiomass was measured as 24,538?±?182?kJ?kgDW?1(5,865?±?43?kcal?kgDW?1). Considering the downstream processing required in each approach, the most promising energy valorization method is anaerobic digestion able to reach values up to 20,862?kJ?Lreactor?1?day?1in continuous systems.