20.109(F12): Pre-proposal WFGreen
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Revision as of 08:32, 29 November 2012
Title of Proposed Project
20.109(F12) Pre-Proposal: Optimizing the Size of Algal Chloroplast Antennea for Bioreactors
Modern American society depends on fossil fuels such as petroleum; however, our reliance on these fuels puts both our economy and national security at risk and the CO2 released is destabilizing our planet’s climate. Because of these issues, many are researching renewable energy sources such as solar panels, hydrogen power, and biological fuels. Although biodiesel is the most petroleum-like fuel among these options, it is less efficient, in part due to the fact that algae tend to be optimized for low-light conditions; we propose a genetic screen in order to find a strain of algae more optimized for direct sunlight.
Currently, the United States uses nearly 8.5 million barrels of gasoline per day in order to power our automobiles, buses, and other methods of transportation. Gasoline is well suited to this task; it is extremely energy-dense (~46 MJ/kg, ~36 MJ/liter), allowing it to be easily transported in order to supply a non-stationary engine. Of all the biological fuels, biodiesel comes the closest: ~42 MJ/kg, ~33 MJ/liter. (In comparison, lithium ion batteries are much less energy dense - 0.7 MJ/kg, ~2.3 MJ/liter.) However, the process of creating biofuels is extremely inefficient. Algae, which are the most efficient, can produce about $foo galloons per acre year with an efficiency of around 0.6%. There are, however, various inefficiencies that can probably be reduced. For example, algae chloroplasts contain large light-gathering complex; an adaptation that helps them live in low-light (200 -400 micromol photon/m2) conditions but often photosaturates under direct sunlight (>2000 photon/m2). Up to 80% of the light energy is wasted this way (JEW Polle et al 2002), and we seek to find the antenna size that is optimal under sunlight.
We will first create a library of mutants of the microalga Chlorella protothecoides, in antennae size and set up outdoor closed bioreactors with these mutants. For a period of seven days, we will daily measure the concentration of