quantitative saccharification based on a 2 h incubation in
72 wt% H2SO4 at 308C followed by a second 1 h incubation
in 4 wt% H2SO4 at 1218C (NREL analytical procedures,
1995). The cell mass was determined by counting colony
forming units on agar plates, as described in Zhang et al.
(2009c).