1. Research Centre Flakkebjerg, Department of Genetics and Biotechnology, Danish Institute of Agricultural Sciences, DK-4200 Slagelse, Denmark, Novozymes A/S, Laurentsvej 55, DK-2880 Bagsværd, Denmark, and Institute for Molecular Biotechnology (Biology VII), Rheinische-Westfälische Technische Hochschule Aachen, 52074 Aachen, Germany