Microalgae and biofuels

Making Biofuel from Microalgae by Philip T. Pienkos, Lieve Laurens and Andy Aden

I was compeled to purchase this recent issue of American Scientist because of the cover article. I am very interested in the possibilities of producing biofuels from the lipids that algae produce because the production of ethanol from corn seems outrageously inefficient and makes little sense as far as renewable fuel sources go. 

The 2005 report "Biomass Feedstock For a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply," or simply the "billion-ton study" that has recently been updated, explains that about 96 billion gallons of bio-based fuels could be harvested from 1.6 billion tons of terrestrial biomass. Unfortunately the current demand is near 200 billion gallons just in the US. And this only being the case if we were to drastically improve the efficiency and ability of obtain maximum theoretical yields for current bio products like switchgrass fermentation, waste from agriculture and forestry, and municipal solid wastes. 

Algae production poses major potential for biofuel production as well as a number of additional byproducts without many of the drawbacks of similar agricultural biofuels. Unlike corn production for ethanol, algae is not a common food source and would not interfere with food production. Many varieties of algae have adapted to almost all aquatic habitats on earth and thus greatly broadens the areas as well as the water types that could be utilized. But as with all new sustainable energy technologies there a number of hurtles that prevent it from even beginning to compete with fossil fuels. 

New and more effective strains of algae must be identified or genetically developed, more effective ways of farming must also be developed, and sustainable use of valuable resources such as water must be kept in mind. In addition, extraction and refining methods need to be improved as well as inventing creative ways of utilizing many of the byproducts. 

Eukaryotic algae possess the highest potential due to their high neutral lipid content, which is important because nearly 100 percent of the triacylglycerols (TAGs) can be converted into fuels. The composition of lipids varies greatly and depends on many factors and a large amount of the lipids are polar and only 30 to 50 percent can be used to produce fuel. "Unlike typical terrestrial oil-producing plants, in which specialized cells yield oils, every algal cell can produce oils." And as with other plant oils, the process of transexterfication allows them to be made into good biodiesel feedstocks. 

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I feel like this is an amazing idea and there is a lot of room here for improved growing and extraction methods and facilities. Although it is in its infancy, this article shows us that the potential for algae to eventually compete as a biofuel agent is become more and more feasible. Like other renewable energy technologies, algae can be produced here in the US and lessens our current dependency on foreign oil. 

Burning carbon-based fuels will always release excessive CO2 and contribute to global climate change and biodiesel is no substitute. If we are to continue to produce greenhouse gases in the long term we need to develop cleaner and more efficient engines that may work in association with electric. In addition, methods for carbon capture and sequestration should be explored. But with the hopes of reduced dependency on coal with the introduction of renewable energy, algae along with others should put a major damper on what we currently pump into the atmosphere.