Batches of wood hydrolyzates were partially deacidi fied using an electrodialysis concentration process to
decrease the inhibitors and concentrate the wood sugars (Datta, 1989). The shake fiask fermentation for the
wood hydrolyzate was conducted in triplicate similar to fermentation for mixed sugars. Erlenmeyer flasks (125ml) containing 50 ml of fermentation medium, which contained 40 ml filter-sterilized partially deacidified
wood hydrolyzates (batches I±VIII), 1.7 g/l filter-sterilized YNB (Difco, Michigan), and 8.83 g/l total nitrogen
nutrients (2.27 g/l urea and 6.56 g/l peptone). Flasks were inoculated with an initial 1.5±3.0 g/l fresh or recycled
C. shehatae FPL-Y-049 and shaken at 100 rpm at 25°C. The wood hydrolyzate was initially diluted 20%
by adding nitrogenous nutrients and cell inoculum. The pH of acid hydrolyzates of various batches was adjusted
to 5.5±6 using 1 M sodium hydroxide. The shake flask fermentation was optimized with various reduced levels
of nitrogen nutrients with fresh or recycled cells in the presence or absence of 10 mg/l zinc sulfate.