1. State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Wuhan 430070, P. R. China
2. Department of Biotechnology & Enzyme Catalysis, Institute of Biochemistry, University Greifswald, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany