Talk of the Nation – Listen to the Story [47 min 21 sec]* Download
A federal renewable fuel standard calls for mixing 36 billion gallons of biofuels into transportation fuel by 2022. But the U.S. produces only one-third of that amount today. Ira Flatow and guests talk about meeting that goal with products like cellulosic ethanol or oil squeezed from algae.
Dr. BRATIS: Sure. Well, I think one thing that’s important to realize to start with is that you can get an awful lot of cellulosic biomass for $60 a dry ton or less. That happens to be $4 a gigajoule, perhaps arcane units, but that corresponds to $23 a barrel. So you’ve got a cost-competitive, and then some, raw material.
The reason that we don’t have a cellulosic biofuel industry today is actually very simple. It’s the difficulty of making reactive intermediates from this raw material.
Basically, nature has evolved biomass, cellulosic biomass, to be tough and resistant to microbial attack. And that really is where the focus is to remove the limiting factor. And that generally involves something called pretreatment, which is non-biological followed by microorganisms that I believe in the advanced configuration will directly ferment the cellulose. For now, people are also talking about producing cellulose enzymes separately that will dissolve this stuff.