3Com founder takes the reins at GreenFuel

Robert Metcalfe, a founder of 3Com Corp. and the engineer who led the development of Ethernet computer networking technology, is taking the helm at a Cambridge start-up that seeks to replace imported oil with home-grown algae.

Metcalfe, a principal at Polaris Venture Partners, a venture capital firm in Waltham, will serve as acting chief executive at GreenFuel Technologies Corp., which has already received a $6.8 million investment from Polaris. Metcalfe replaces Cary Bullock, who will stay on as a director of the company and vice president of business development.

Metcalfe, a computer engineer, admitted he's no expert on biotechnology. "I don't know how to do any of it, nor will I learn," he said. Instead, he'll focus on raising additional funding for GreenFuel and seeking a permanent chief executive. "My title is interim CEO, with a capital i," he said.

GreenFuel was founded by Isaac Berzin, a chemical engineering researcher at the Massachusetts Institute of Technology. Berzin developed a system that pumps carbon dioxide from conventional electric power plants into a "bioreactor" that contains water and algae -- tiny green plants. The carbon dioxide causes rapid growth of the algae, which can be filtered from the water and processed into a substitute for diesel oil, and ethanol for mixing with gasoline. The leftover algae can also be processed into animal feed.

The process has worked well on a small scale, but to become profitable, GreenFuel needs to produce algae in industrial quantities. It's trying to do so at a pilot plant in Arizona. But the plant has been shut down because it produced algae faster than it could be harvested. "Their unexpected density limited light and nutrient supply, which caused them to start dying," Metcalfe said in a memo to GreenFuel employees and investors. In addition, the process has proven more costly than expected. So Metcalfe plans to move quickly to a new generation of technology that costs less and allows for easier harvesting.

To preserve GreenFuel's cash reserves during the transition, Metcalfe has slashed the company's payroll from 43 employees to 28. "These are all excellent people," he said. "It is extremely painful to part with them."

John Preston, a senior lecturer in entrepreneurship at MIT's Sloan School of Management, said processes that work well in a lab often hit roadblocks when expanded to an industrial scale. Preston said Metcalfe has the managerial skills and connections to get GreenFuel over the hump. "If there's anyone out there who can really make that company fly, it's Metcalfe," he said.

Hiawatha Bray can be reached at bray@globe.com.