Algal Research, 45, 2020
Highlights
- Bioprospecting for native sucrose-accumulating microalgal strains
- Induction of sucrose and lipid accumulation using seawater
- Mild sugar-extraction conditions and direct conversion into ethanol
- Modeled productivity of 4200 L ethanol·ha−1·year−1 in raceway ponds in Brazil
Abstract
Microalgal biomass is increasingly considered a promising feedstock for the production of bioethanol because it has simpler biochemical composition and structural features than plant feedstocks. However, it still requires hazardous and/or expensive acid or enzymatic saccharification processes before its conversion into ethanol by fermentation. To bypass this limitation, we identified microalgal strains that accumulate up to 10% (w/w) of sucrose, a readily fermentable sugar. Conditions were optimized to produce sucrose in half-strength seawater, as well as efficient extraction by very mild procedures, and conversion into ethanol. We present a model based on cultivation in environmental photobioreactors that predicted a productivity of 4200 L ethanol·ha−1·year−1 in raceway ponds in Brazil, approaching the average sucrose and ethanol productivity from sugarcane.
Keywords
Biofuels, Saccharification, Sugars, Bioethanol, Biorefinery, Water footprint