Michigan State University, East Lansing researchers and colleagues have grown corn engineered to produce key enzymes needed to break down cellulose into sugar for use in making biofuel.

The three enzymes added to the transgenic corn came from a hot-spring microbe (breaks cellulose up), a fungus (breaks cellulose into a pair of sugar molecules), and a cow’s stomach microbe (breaks paired sugar molecules into simple sugars).

To keep the enzymes from destroying cell walls while plants are growing, they manipulated gene expression so that the proteins were only produced in vacuoles–closed-off cellular storage compartments.

Current efforts to produce cellulose-digesting enzymes have focused on inserting enzyme-making genes into common microbes such as E. coli and growing these enzymes in commercial bioreactors, which require vast amounts of energy for enzyme production.