ExxonMobil and California-based Synthetic Genomics Inc. will scale back a four-year-old project to develop biofuels derived from algae. The $600 million program, which was highlighted in ExxonMobil commercials, originally was to select, modify, and scale up algae for biofuels production. The partners will now focus on basic algal genomics research. So far, the firms have spent $100 million on the project, according to an SGI spokeswoman; financial details for future work were not disclosed. Since 2009, the researchers have “gained considerable knowledge about the challenges in developing economical and scalable algae biofuels,” the firms explain in a statement. Other large oil firms have pulled away from earlier support of biofuels. Chevron has been lobbying against California’s low-carbon fuel standard, which the company helped write in 2007. And the head of BP Biofuels, Philip New, told attendees of a recent biofuels conference that many technologies have fallen short of commercial potential.