Enhanced Cellulase Production from Bacillus subtilis by Optimizing Physical Parameters for Bioethanol Production

Figure 4

Simultaneous saccharification and fermentation (SSF) profile of wild grass (A. hymenoides) using B. subtilis AS3 cellulase and Z. mobilis in bioreactor (●) cell OD measured at 600 nm, (▲) ethanol concentration (g/L), (▼) reducing sugar (g/L), and (∘) specific activity (U/mg) with time, respectively. Cultivation conditions: working volume 1 L in 2 L bioreactor; initial pH 6.0; temperature 30°C; shaking 120 rpm; aeration rate 1 vvm incubation period 72 h; sampling interval every 6 h.