J. Craig Venter, the scientist who mapped the human genome, just helped Exxon Mobil Corp. strike a balance of keeping algae fat enough to produce oil but spry enough to grow quickly, a breakthrough that could enable widespread commercialization of algae-based biofuels, Bloomberg reports.

Exxon and Venter’s Synthetic Genomics Inc. used advanced cell engineering to more than double the fatty lipids inside a strain of algae. Venter, who co-founded Synthetic Genomics says the development is a significant advancement in the quest to make algae a renewable energy source. The discovery is being published in the July issue of the journal Nature Biotechnology.

When Exxon Mobil announced its $600 million collaboration with Synthetic Genomics in 2009, the oil company predicted it might yield algae-based biofuels within a decade. Four years later, Exxon executives conceded a better estimate might be within a generation. Even with this newest discovery however, commercialization of this kind of modified algae is decades away.

Most renewable fuels today are made from plant material, including corn, corn waste and soybean oil. Algae has long been considered a potentially more sustainable option; unlike those traditional biofuels, it can grow in salt water and thrive under harsh environmental conditions. And the oil contained in algae potentially could be processed in conventional refineries.