1. a Technical University of Graz, Institute of Environmental Biotechnology, Petersgasse 12, A-8010 Graz, Austria; University of Maribor, Faculty of Mechanical Engineering, Department of Textile Materials and Design, Smetanova ulica 17, SI-2000 Maribor, Slovenia
2. b University of Maribor, Faculty of Mechanical Engineering, Department of Textile Materials and Design, Smetanova ulica 17, SI-2000 Maribor, Slovenia
3. c Technical University of Graz, Institute of Environmental Biotechnology, Petersgasse 12, A-8010 Graz, Austria