Exploiting Photosynthesis for Biofuel Production

During the recent “Energy Outlook and Modeling Conference” of March 2006 in Washington DC, it was estimated the world current energy consumption in 100 “Quads,” where one Quad corresponds to about 25 million of oil equivalent tons (MTep, http://www.eia.doe.gov/oiaf/aeo/conf/). Nowadays, over 85% of world energy demands are met by the combustion of fossil fuels: coal, oil, and natural gas. Current oil reserves are estimated to be about 1,277 billions of barrels and, assuming a stable consumption, they would be sufficient for next 42 years. However, in the middle-term oil utilization is expected to rise of 1.6% every year thus making reserves exhaustion even faster (http://www.eia.doe.gov/oiaf/aeo/conf/pdf/petak.pdf). It is thus clear that to sustain our lifestyle to find alternative and renewable sources of energy is a striking and urgent need.

Besides the problem of fossil reserves depletion, the massive combustion of fossil fuels in the past decades also had a high environmental impact. In fact, this leads to releases of large amounts of carbon dioxide and other pollutants in the atmosphere. However, these emissions are reassimilated by natural processes, which cannot keep the pace of the present CO₂ production rates. In fact, every year the forests are able to fix about 1 billion of tons of carbon in organic matter and further 2 billion of tons are fixed in the ocean every year by the sea photosynthesis, but the CO₂ emissions caused by the human activity are about 6 billion of tons. So the balance is positive and every year 3 billion of tons increase the global level of CO₂ in the atmosphere (Fig. 2.1).