Researcher Says Petroleum-Based Fuel Additive Can Be Produced Organically

A new bio-based method for producing a heavily used fuel additive and industrial chemical now made from petroleum products has been developed by an Iowa State University researcher.

Thomas Bobik, professor of biochemistry, biophysics and molecular biology, invented a process for manufacturing isobutene (isobutylene) by identifying a new, natural enzyme that produces the fuel organically.

Bobik's enzyme makes it possible to convert the glucose found naturally in plants to make isobutene. The enzyme is found in about half of all organisms in the world.

Isobutene is a gas used to produce chemicals and manufacture fuel additives, adhesives, plastics and synthetic rubber.

It can be chemically converted to isooctane, which is a fuel that could be used to replace gasoline additive methyl tert-butyl ether (MTBE), which can be environmentally harmful.

Produced from petroleum products, isooctane is used in gasoline to stop engine knocking and other problems.

Bobik believes there could be huge benefits to the biofuels industry.

“I would emphasize that we are very early on in the process,” he says in a statement. “But isobutene has some special properties that could have a big impact.”

While patent applications proceed, Bobik will not disclose the specific enzyme.

He believes there will be environmental and cost benefits to the biofuels industry from using his naturally occurring, biological process to produce isobutene.

One of the biggest expenses in producing the biofuel ethanol is the cost of separating the ethanol from the water where it is made. Bobik says his process will not include the cost of separation.

“Isobutene is a gas, so we can imagine that it will be easy to remove the isobutene from the vessel in which it was made, and that should be a very cheap and efficient way to purify the biofuel,” he says.

For the moment, Bobik says, the process takes too long.

“The activity of the enzyme (in making the isobutene) is low,” he says. “It's too low for commercial application. So we're trying to use directed enzyme evolution to improve the activity of the enzyme so it can become commercially viable.”

Directed enzyme evolution is the effort to engineer enzymes to perform certain functions. In this case, it is trying to find a way to get the enzyme to produce isobutene more quickly than in nature.

Bobik says progress is being made and, perhaps, within 10 years motorists may be using a bio-based, environmentally friendly ingredient in their gas tanks every time they fill up.