Exogenous enzyme cocktails used in cellulosic ethanol production are more effective than they’ve ever been, but if Masood Hadi’s work on the Trojan Horse of enzymes works the way he thinks it does, forget about the need for those extravagant enzyme mixtures. Hadi, a biochemist from Sandia National Laboratory, has been working on a genetically modified plant that houses what he has coined a Trojan Horse type of enzyme that, when put through a traditional deconstruction process typically used with cellulosic material, becomes resurrected and chews up the cellulosic material on the way to sugar production. The research, which Hadi has been working on for the past three years, is based on a process that embeds an endoglucanase enzyme into a genetically modified plant like Arabidopsis, tobacco or a model of switchgrass. “The enzyme is engineered in such a way that it is catalytically dead,” he says. At least, Hadi says, until the plant housing the embedded enzyme is put through a deconstruction process. “Before that,” he explains, “the enzyme is just a protein,” but once the deconstruction process, such as a dilute acid treatment, happens, the enzyme is activated. In a typical dilute acid process, exogenous enzymes become active at roughly 120 degrees Celsius, but using Hadi’s embedded enzymes, activity would start at only 80 degrees.

After working to engineer the enzymes, Hadi began working with the USDA to perform the plant transformations and characterizations before bringing the plant material back to his lab to complete structure function relationship tests that indicated the amount of sugar the plants were producing. The results of the tests to this point show that for pumping out sugar, “all you needed was that one enzyme and you would get a lot more sugar,” Hadi says. “In this process, you don’t have to add any exogenous enzymes—we’ve completely eliminated the need.”

The work to create a “resurrectable” enzyme is not complete yet according to Hadi, and while his efforts will continue to perfect the process, he isn’t solely focused on enzymes. With the help of engine combustion experts from Sandia, Hadi is involved in a fungi-based project aimed at finding certain types of fungi that produce hydrocarbons more suitable for today’s combustion engines. Hadi’s role in the effort will remain in his field of biochemistry, looking at the pathways through which selected fungi strains produce the volatile organic compounds most compatible with combustion. The fungi-combustion project is expected to take roughly three years. 

—Luke Geiver