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

Abstract

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 315.4g/l dry matter, and then the mixture was liquefied at 80°C for 90min by using alpha-amylase (3532AAU/kg CF) and beta-glucanase (2812U/kg CF). SSF of liquefied mash of cassava was performed at 30°C with the simultaneous addition of two glucoamylases (Distillase ASP at 540GAU/kg CF and Amigase Mega L at 0.035% w/w), active dry yeast (1.5×107 cells/l), urea (12mM) and KH2PO4 (4mM). Under these conditions, the SSF process finished after 72h. 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.