Algae

Microalgae represent a promising feedstock for the production of biofuels as well as the production of other bulk chemicals, food and feed. They are attractive alternatives compared to terrestrial oleaginous species because their productivity can be boosted to higher levels and they do not have to compete for land suitable for agriculture. These advantages are based on the simple fact that microalgae can be contained in a watery environment in which all growth factors can be optimized as for example carbon dioxide and nutrient levels, temperature and light distribution.
Growing microalgae in a contained environment, being either raceway ponds or closed low-cost outdoor photobioreactors, is technically challenging and the associated costs and energy requirement need to de drastically reduced before this process can be successfully commercialized.

Within Wetsus, the Dutch centre of excellence of sustainable water technology, a research theme ‘biofuels from microalgae’ was started in 2008 (www.wetsus.nl). The objective of this research program is to realize breakthroughs leading to the successful commercialization of a microalgae production process for biofuels feedstock. This research theme is supported by 13 companies listed below and carried out by 7 PhD researchers focusing on different issues related to this process:

• Enhancement of lipid productivity. Current oil-accumulating microalgae species accumulate lipids in a non-growing phase. The objective is to steer metabolism in the direction of concurrent microalgae growth and lipid accumulation.
• Enhancement of photosynthetic efficiency. In well-designed photobioreactors light is the growth-limiting factor. The objective of this study is to enhance the conversion efficiency of (sun)light into lipid-rich biomass by modifying light distribution on the reactor surface.
• Carbon dioxide supply and oxygen removal. Depletion of carbon dioxide (CO2) or the accumulation of oxygen (O2) directly limit productivity, and the associated gas transfer reflects a major energy input for microalgae production processes. The objective of this study is therefore to enhance the rates of transfer of CO2 and O2.
• Microalgae biorefinery. The objective of this study is the development of a simple process to extract functional proteins for food and feed in order to be able to use a larger fraction of the microalgae biomass and make value out of it.
• Microalgae harvesting. Microalgae are unicellular and difficult to concentrate from the dilute product streams. The objective is to develop a simple pre-concentration step based on flocculation.
• Scenario analysis. The whole microalgae production process chain is complex and depends on several external factors. As an example microalgae production can be combined with CO2 removal from combustion gasses and nutrient removal from wastewater. The objective of this scenario analysis is to specify the critical factors in the process design and to search towards solutions that anticipate to the developments in the environment of algae production plants.