Sapphire Energy, an American company, recently announced that they have produced a “renewable 91 octane gasoline that conforms to ASTM (American Society for Testing and Materials) certification”, using photosynthetic microorganisms, such as algae. A more detailed overview of the production process was not divulged, but according to the Sapphire Energy press release, “company scientists have built a platform that uses sunlight, carbon dioxide, photosynthetic microorganisms (algae) and non-arable land to produce carbon-neutral alternatives to petrochemical-based processes and products”. The company’s research partners include the United States Department of Energy (US-DOE) Joint Genome Project, the University of California at San Diego, Scripps Research Institute and the University of Tulsa in Oklahoma.

Related information: octane number in gasoline
http://www.petrolprices.com/about-fuel.html
http://en.wikipedia.org/wiki/Octane_rating.