Test strains of Pichia stipitis and Candida shehatae (Jeffries and Livingston, 1992) were from the FPL yeast
collection, which is stored in 15% glycerol at -80°C. These strains were grown and maintained on fresh plates
of yeast extract peptone xylose (YEPX) agar (see Media) for 48 h at 30±32°C.