Effects of the liquid vapor oxygen transfer coefficient (kLα) on ethanol production from cassava residue and analysis of the fermentation kinetics

Abstract

Cassava residue is the solid waste generated from the production of tapioca starch and has considerable reuse value. In this study, cassava residue was examined as a hydrolysate for ethanol production, and the effects of different liquid phase oxygen transfer coefficients (kLα) on the production of ethanol from cassava residue hydrolysates were studied. Based on analyses of dissolved oxygen and a set of optimal experimental schemes, dynamic models of cell growth and product synthesis were optimized, using MATLAB. When kLα was 85, fermentation was optimal; the ethanol titer reached 23.14 g L−1 at 72 h and cell growth reached 6.23 g L−1 at 96 h. Additionally, experiments were performed according to the dissolved oxygen curve obtained under these conditions. The resulting ethanol titer was 24.43 g L−1 (72 h) and the cell mass was 6.45 g L−1 (96 h).