Long-term operation of continuous high cell density culture of Saccharomyces cerevisiae with membrane filtration and on-line cell concentration monitoring

An internal membrane-filtration bioreactor system with periodic fouling rem oval and on-line cell measurement was employed for long-term continuous eth anol production from glucose in order to prove its performance and practica lity. The bioreactor system developed in this study was successfully operat ed for 2 months with no problems in the maintenance of filtration flux. The maximum productivity obtained in this study was about 13 g/l-h which was c a. 3.3 times higher than that obtained in a conventional chemostat without cell retention by membrane. In another run of continuous culture, the laser turbidimeter used for the on-line monitoring of cell concentration showed a stable performance for 45 days without sensitivity loss due to fouling.