Growth and residual cellulose concentration (a) and product concentrations (b) during classical batch fermentation (I) and reinoculated culture (II) of C. cellulolyticum with 29.1 g of cellulose liter−1. Arrows, reinoculation times. ◊, biomass; ⧫, cellulose; ■, ethanol; ○, acetate; ▴, lactate.