Botryococcus braunii
With the availability of petroleum diminishing, the largest world reserves of petroleum existing in politically unstable regions and, most importantly, the adverse effects of burning petroleum on global climate, there is a critical need to find alternative, sustainable, and carbon-neutral fuels. It is well known that some plants produce significant quantities of oil and since they use CO2 from the atmosphere to synthesize this oil, burning this same oil as a fuel is carbon neutral.
It is clear from the scientific literature that microalgae, or at least some species of microalgae, have the potential to produce significant amounts of oil. Indeed, it is estimated that some fast-growing species that produce over 50% oil (by dry weight) could provide enough oil to replace petroleum diesel in the US if approximately 1% of the total land that is now dedicated to farming and grazing in the US (i.e., about 10 million acres) were transformed into algae farms. Algae, including microalgae, have been cultivated around the world for food, vitamins, nutraceuticals, edible oils, fertilizer, animal feed and other products. Why then is so little biofuel currently being produced from algae?
The short answer is that we don’t know how to do it on a scale that would be economical and that would not adversely impact our environment.
From 1978 to 1996, the Office of Fuels Development at DOE funded a program under the National Renewable Energy Laboratory known as the “Aquatic Species Program.” The research began as a project looking into using algae to sequester CO2 emitted by coal and natural gas power plants. When it was observed that some algae species produce significant quantities of oil, the project shifted its focus to growing oil-producing algae as a potential source of biodiesel. This research indicated that many species produce oil, but few species have what it would take for oil production. For production, the requirements include: significant oil content per cell, a useable fatty-acid profile, rapid growth rates, reasonable nutrient requirements and other growth conditions, hardiness to environmental fluctuations, and resistance to invasion from other species. All of these features can be manipulated by the appropriate selection of species and selective breeding. In fact, fast-growing algae have been studied extensively for not only oil (lipid), but also a variety of other valued products including biomass, hydrogen, hydrocarbons, vitamins, alcohols, carbohydrates, methane, and syngas.
October 3, 2008
