Engineering strategies were applied to improve the cell growth, CO2 fixation ability, and carbohydrate productivity of a Scenedesmus obliquus CNW-N isolate. The resulting carbohydrate-rich microalgal biomass was subsequently utilized as feedstock for ethanol fermentation. The microalga was cultivated with 2.5% CO2 in a photobioreactor on different operation modes. Semi-batch operations with 50% replacement of culture medium resulted in the highest CO2 fixation rate (1546.7mg L-1d-1), carbohydrate productivity (467.6mg L-1d-1), and bioethanol yield (0.202g/g biomass). This performance is better than most reported values in the literature. The microalgal biomass can accumulate nearly 50% carbohydrates, as glucose accounted for nearly 80% of the total carbohydrate content. This glucose-predominant carbohydrate composition of the microalga is well suited for fermentative bioethanol production. Therefore, using the proposed carbohydrate-rich microalgal biomass both as the carbon sink and as the feedstock provides a feasible alternative to current carbon-reduction and bioethanol-production strategies.
All Science Journal Classification (ASJC) codes
- Environmental Engineering
- Renewable Energy, Sustainability and the Environment
- Waste Management and Disposal