[1] Ctr Energy & Environm, Minneapolis, MN 55401 USA
[2] Univ Minnesota, Dept Bioprod Engn, St Paul, MN 55108 USA
[3] Univ Minnesota, Dept Biosyst Engn, St Paul, MN 55108 USA
[4] Univ Calif Berkeley, Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA