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uni'wissen 1-2013_ENG

­experts in bioinformatics, modeling, and metabo­ lism studies from the Humboldt University of Berlin, the University of Rostock, Max Planck In­ stitutes in Potsdam and Magdeburg, and the company Algenol Biofuels Germany GmbH in Berlin. The researchers are focusing especially on improving the production of enthanol in the car­ bon metabolism of cyanobacteria. The two liters of ethanol per square meter and year they have managed to achieve so far is already three times higher than the yield of biofuel from sugarcane, when one takes into account the fact that the former can be harvested twice a year. For a se­ ries of experiments conducted in Berlin at the test facilities of Algenol Biofuels Germany GmbH, the scientists are using two genetically modified model organisms. The cyanobacteria swim in plastic-film photobioreactors filled with 500 liters of seawater. With the help of sunlight, they can convert CO2 pumped into the transpar­ ent vessels into ethanol as well as several other high-quality hydrocarbons, such as isoprene and ethylene, which can also be used for the production of plastics. Ensuring Genetic Stability The alcohols obtained from the bacteria are high-quality fuels. They are less toxic than con­ ventional gasoline or petroleum and have a high octane rating – making them less likely to self- ignite and burn uncontrollably. Moreover, an analysis conducted at the Georgia Institute of Technology, USA, shows that the ethanol pro­ duction method used in the project leaves a sig­ nificantly lower carbon footprint than the production of gasoline from crude oil. Ethanol should provide the researchers with an initial ex­ ample that it is possible to adapt the photosyn­ thetic metabolism of cyanobacteria to the production of biofuels. Even in the small-scale conditions of the lab­ oratory, ethanol stores around 90 percent of the carbon fixed from CO2. “However, the process of using organisms that create their energy from light to produce ethanol is far from being a straightforward affair,” emphasizes Annegret Wilde. She is concentrating especially on find­ CO2 CO2 Every cell is a tiny ethanol factory: The diagram shows how cyanobacteria produce biofuel. Source: Algenol, Illustration: Tamara Klaas “The key question is whether using cyanobacteria to produce ethanol can be made profitable” 10