Another probable explanation of slower glucose utilization is
osmotic stress caused by a large concentration of glucose and other
toxic compounds that are still present when overliming at pHs 8
and 9 (Saint-Prix et al., 2004). From the beginning, the steady drop
of glucose concentration in pH 8 and 9 overliming hydrolyzates
could be detected. The drop in glucose concentration could be
due to consumption by the remaining yeast capable of naturally
adapting themselves to higher concentration of toxic products
(Taherzadeh and Karimi, 2011). The yeasts then consumed the
glucose until the concentration reached almost 0 g/L after 48 h.
The result from Fig. 2b gives evidence that pHs 8–12 could be a
suitable overliming pH range for S. cerevisiae