Carbon dioxide bio-fixation and wastewater treatment via algae photochemical synthesis for biofuels production

Abstract

We are faced with the problem of energy/carbon dioxide (CO₂) in the coming decades. Microalgae has been considered as one of the most promising biomass feedstocks for the production of biofuels. Meanwhile, the productivity of these photosynthetic microorganisms in converting CO₂ into carbon-rich lipids, which are only a step or two away from biodiesel, significantly exceed that of agricultural crops without competing for arable land. Worldwide, research and demonstration programs are being carried out to develop the technologies required to expand algal lipid production from a craft to a major industrial process. This paper describes the recent advances on microalgae used for biofuel (e.g., biohydrogen, biodiesel and bioethanol) production, including their cultivation, harvesting, and processing. In addition, the various aspects associated with the design of microalgae production units are described, providing an overview of the current state of the development of algae cultivation systems (photobioreactors and open ponds). Algal cultivation systems integrated with algae-based biorefineries could yield diverse bioresources, such as biodiesel, green gasoline, bio-jet fuel, isolated proteins, food starches, textiles, organic fertilizers, which can mitigate the costs of biofuel production. Algae cultivation becomes a closed-loop engineered ecosystem by utilizing the energy, nutrients and CO₂ held within residual waste materials to provide all necessary inputs except sunlight. Consequently, developing this biotechnology is a tangible step towards a waste-free sustainable society.