Approximately 90% of the ethanol was produced during the first
48 h of the fermentation. From a process-economy aspect, it may
be desirable to further shorten this residence time. It seemed that
a longer residence time was required at higher DM concentrations,
i.e., the hydrolysis yield was lower. This might be due to some
inhibitory effects; e.g., an increase in end-product inhibition as
the sugar uptake rate was lower, but it could also be a reflection
of less efficient mass transport (Sassner et al., 2006).
concentration yet reported and exceeds the technical and economic
limits of industrial-scale alcohol distillation