Continuous simultaneous saccharification and fermentation of raw starch in a membrane reactor

A kinetic model for simultaneous saccharification and fermentation (SSF) of raw starch is proposed. The model includes the effect of ethanol on an active site for saccharification and the decay of a raw starch affinity site. The kinetic parameters were determined by using the experimental results of a batch saccharification and a long-term repeated-batch SSF of raw sweet potato starch. From analysis of the experimental results it is concluded that two subsites took part in ethanol inhibition, and that the inactivation of the raw starch affinity site was induced by adsorption of glucoamylase onto raw starch. The proposed kinetic model successfully predicted the progress of continuous SSF in a membrane reactor.