(348f) Kinetic Model for Consecutive Batch Ethanol Fermentation By Flocculating Yeast Under Automatic Control Mediated By Redox Potential

A kinetic model group was proposed to describe consecutive batch (CB) ethanol fermentation by using flocculating yeast cell, which accumulated biomass by fully recycling cells and thus accelerated ethanol production than single batch (SB), especially when redox potential monitoring was applied to accurately indicates the end time point of every batch and automatically control this process (automatic consecutive batch, ACB), more waiting time were saved than manual sampling at fixed intervals (manual consecutive batch, MCB). Based on simulation from the model that fitted the experimental data for 200 and 240 g glucose/l ACB fermentation well with R²>0.9, biomass in CB was higher than SB since 2nd batch, but the total biomass was less than multiple SBs, which made full use of biomass and reduce the substrate consummation for total biomass formation. In theory, the final ethanol concentration were same no matter what kind of process, hence the different between 3 kinds of fermentation was fermentation time. At the first 14 batches (200 g/l) and 8 batches (240g/l), the CB fermentation time is shorter than SB, and ACB is even shorter than MCB. Therefore, ACB reached the highest ethanol productivity.