Pilot scale simultaneous saccharification and fermentation at very high gravity of cassava flour for ethanol production

• We developed a very high gravity process to produce ethanol from cassava flour.
• A dry solid content of 315.4 g/l was achieved at lab and pilot scale.
• We reached 17.2% v/v ethanol (86.1% of theoretical ethanol yield) at lab scale.
• We reached 16.5% v/v (83.6% of theoretical ethanol yield) at pilot scale (100 l).

We developed a simultaneous saccharification and fermentation (SSF) process of cassava flour at very high gravity (VHG). Cassava flour (CF) was dissolved in water to reach 315.4 g/l dry matter, and then the mixture was liquefied at 80 °C for 90 min by using alpha-amylase (3532 AAU/kg CF) and beta-glucanase (2812 U/kg CF). SSF of liquefied mash of cassava was performed at 30 °C with the simultaneous addition of two glucoamylases (Distillase ASP at 540 GAU/kg CF and Amigase Mega L at 0.035% w/w), active dry yeast (1.5 × 107 cells/l), urea (12 mM) and KH2PO4 (4 mM). Under these conditions, the SSF process finished after 72 h. The ethanol content achieved 17.2% v/v corresponding to 86.1% of the theoretical ethanol yield at lab scale and decreased to 16.5% v/v corresponding to 83.6% of the theoretical ethanol yield at pilot scale. Therefore, the SSF of cassava flour under VHG condition could have a great potential for the ethanol industry in Vietnam and South East Asia.