In theory, biofuels programs could gives us a ready supply of carbon-neutral fuels for use in everyday applications, but the process is expensive and inefficient.
[On the other hand, is it really carbon-neutral?] Researchers have been looking for ways to improve biofuel synthesis, speed up the process, reduce energy inputs, and reduce costs. The feedstocks vary, from wood chips to switchgrass and cornstalks, things that are readily available and aren’t part of the food chain. The problem is that getting from feedstock to biofuel, requires a lot of chemical processes.
The key to biofuel synthesis lies in the chemistry that hydrocarbon fuels share with the molecular chains that make up plant material. Simple sugars, such as glucose [C6H12O6], are very similar in composition to fuels, such as octane [C8H18], a component of gasoline. These simple sugars are relatively easy to convert into a usable fuel, but long-chain sugars require more chemistry to break down. Lignocellulose [C6H10O5], for example, may link over 10,000 times, and makes up the bulk of plant material.
Recently, focus has been on a fungus that was first discovered in the 1940s, trichoderma reesei. The fungus has a unique ability to metabolize complex sugars, such as those that make up the canvas tents, whose source material is hemp, cotton, or linen [all plant fibers] that WWII soldiers slept in. Today, researchers might be able to put T. reesei’s complex enzymes to good use breaking down the long-chain sugars that make up biomass feedstocks. If they can isolate T. reesei’s specific enzyme combination and tune it to feedstock sugars, biofuel synthesis might be reduced from from months to days.
In a recent paper, published by the US Department of Energy’s Pacific Northwest National Laboratory [PNNL], chemist Aaron Wright says, “Identifying exactly which enzymes are doing most of the work… is crucial for making biofuel synthesis an economical process. We’re trying to keep tabs on the precise activity of every enzyme as each goes through a very complex process… We can test the whole mixture, and we can also tease out each individual contribution. People have not been able to do that all at once before.” [italics mine]
Image © PNNL