Plants show the way

University of Central Florida professor Henry Daniell has developed a groundbreaking way to produce ethanol from waste products such as orange peels and newspapers. His approach is greener and less expensive than the current methods available.

Daniell's breakthrough can be applied to several non-food products like sugarcane, switchgrass and straw.The technique uses plant-derived enzyme cocktails to break down orange peels and other waste materials into sugar, which is then fermented into ethanol.

Producing cellulosic ethanol -- ethanol that comes from wood or the non-edible parts of plants, is tricky. Depending on the waste product used, a specific combination or "cocktail" of more than 10 enzymes is needed to change the biomass into sugar and eventually ethanol. Orange peels need more of the pectinase enzyme, while wood waste requires more of the xylanase enzyme. All of the enzymes Daniell's team uses are found in nature, created by a range of microbial species, including bacteria and fungi.

This finding is significant as it is cheap and also results in lesser emissions than conversion of corn starch into ethanol (which produces more greenhouse gas emissions than gasoline does.)
It also makes good use of abundant waste.

Tobacco was chosen as an ideal system for enzyme production for several reasons. It is not a food crop, it produces large amounts of energy per acre and an alternate use could potentially decrease its use for smoking.

Meanwhile, scientists in France have transformed the chemical energy generated by photosynthesis into electrical energy by developing a new biofuel cell.

Photosynthesis is the process by which plants convert solar energy into chemical energy. In the presence of visible light, carbon dioxide (CO2) and water (H20) are transformed into glucose and O2 during a complex series of chemical reactions.

Researchers at the Centre de Recherche Paul Pascal (CNRS) developed a biofuel cell that functions using the products of photosynthesis (glucose and O2) and is made up of two enzyme-modified electrodes.

The cell was then inserted in a living plant, in this case a cactus. Once the electrodes, highly sensitive to O2 and glucose, had been implanted in the cactus leaf, the scientists succeeded in monitoring the real-time course of photosynthesis in vivo. They were able to observe an increase in electrical current when a desk lamp was switched on, and a reduction when it was switched off.

Furthermore, the researchers showed that a biofuel cell inserted in a cactus leaf could generate power of 9 μW per cm2. Because this yield was proportional to light intensity, stronger illumination accelerated the production of glucose and O2 (photosynthesis), so more fuel was available to operate the cell. In the future, this system could ultimately form the basis for a new strategy for the environmentally-friendly and renewable transformation of solar energy into electrical energy.

Remember, after two billion years of evolutionary improvements, photosynthesis only converts about one percent of the solar energy falling on leaves into chemical energy and even taht depends on soil quality, water and nutrients availability. Will technology beat Nature in this game? Any bets?