Ethanol alternative: Purdue professor tells of attempts to modify trees

Mellan spoke Tuesday in Martinsville during the Morgan County Extension Agency’s annual dinner. He talked with the audience about his attempts to genetically modify poplar trees to help meet the need for ethanol in the United States.

He said ethanol production needs other sources besides corn to satisfy Americans’ insatiable need for gasoline. He said 14 billion gallons of ethanol were produced in 2014, and made up 15 percent of gasoline sold in Indiana. But people in the United States used 135 billion gallons of gas per day in 2014.

Part of Mellan’s solution to this problem and expectation of raising the ethanol percentage in gas to 30 percent by 2030 is to engineer poplar trees. He said these are true poplars — cottonwoods and ashwoods.

The trees grow fast — about 15 feet per year — and end up growing to 90 or 100 feet tall. And they grow in regions all across the United States. But Mellan said it has been quite an experience engineering new trees to make it easier to get to the sugars needed for fermenting fuel. Poplar trees yield 10 percent more ethanol than corn or other methods. And instead of having to store or get rid of biomass waste — which they have to do when using corn to create ethanol — trees redistribute minerals back to the soil requiring less need for fertilizer.

Poplar trees are also used for plywood, pallets, interior trim and paper. As it is, when paper is produced, the sugars are burned. But Mellan said when he is able to change the composition and building blocks of the trees, it will make getting to the sugars much easier. There are genetically engineered trees grown on the Purdue Campus and Mellan is continuing his research, trying to get 98 percent of the sugars — leaving the rest of the trees to be used for higher-value items.

Mellan said through Spero Energy, he is performing biofuels research. He believes the U.S. needs a suite of biomass crops to secure energy self-sufficiency.