Abstract

Land-based bioenergy crops create serious economic and environmental concerns, which include the sequestering of huge areas of arable land or ecologically sensitive regions (such as rain forests) for their growth, the introduction of competition to food production, and a concomitant increase in the price of staple food. In contrast, aquatic-based large-scale algal culturing facilities can be sited on any land, including waste or industrial sites. Moreover, algal productivity can be much higher than land plants per unit area, due to their fast growth rates.

Algae display a remarkable degree of metabolic versatility, with many species able to produce high levels of hydrocarbons, some of which are stored in the cell wall; essentially these algae produce and excrete diesel! They can also divert photosynthetic energy into another ready-to-use fuel, hydrogen or electricity. In addition, algal growth can be directly coupled to other industrial processes, in particular the scrubbing of CO2 from flue gas and the removal of nitrates and phosphates from wastewater, which not only has a cost benefit, but can reduce the carbon footprint of industrial processes.