Robot, Yeast Combo May Mean More Ethanol

The robot is the centerpiece of an automated system called the "plasmid-based functional proteomics work cell." According to Stephen Hughes, a molecular biologist with the ARS National Center for Agricultural Utilization Research in Peoria, the system is the first of its kind to fully automate several procedures that have traditionally been carried out by hand—human hand, that is.

A short list of functions includes extracting genetic material from the cells of plants, microbes and other organisms; making DNA copies of genes; inserting the copies into Escherichia coli; culturing these bacteria so that the copies can be sequenced and their proteins identified; and inserting desirable genes into yeasts used to make ethanol.

Thanks to the fast, precise movements of its mechanized arm, the robotic system can carry out such tasks hundreds—or even thousands—of times faster than a human could, notes Hughes. He and colleagues at the ARS center's Bioproducts and Biocatalysis Research Unit codeveloped the system with a team from Hudson Control Group of Springfield, N.J., starting in 2004.

Of particular interest is using the robotic system to genetically modify new strains of Saccharomyces yeast that can metabolize sugars locked up within corn fiber—something these microbial workhorses have so far failed to do.

Currently, only the starch from corn and other grain crops is being converted commercially into the sugars from which ethanol is derived. With the Saccharomyces yeasts now used, this equates to nearly three gallons of ethanol from a bushel of corn. Using new strains capable of breaking down corn fiber could potentially squeeze 10 percent more ethanol from the grain, Hughes and colleagues estimate.