Total solids of >25% achieved by DA pretreatment of rice straw at pilot scale. Optimum parameters were 0.35 wt% acid concentration, 162 °C and 10 min. At a high solids (20 and 25 wt%) enzymatic hydrolysis was conducted. Overall glucose recovery was 71 and 89% at 10 and 50 FPU/g residue. Overall sugars (C6 + C5) recovery on mass basis was 77% at 50 FPU/g residue.