A flow dialysis cell for on-line measurement of glucose in fermentation broth

A plate flow dialysis cell, employing an acetate cellulose ultrafiltration membrane, was designed and tested for applicability to on-line sampling in fermentation. The glucose contained in effluents of both sample stream channel (Channel A) and carrier stream channel (Channel B) was determined with an enzyme electrode flow injection analysis system. Glucose penetration rate was defined as Rp, Rp = Gb/(Ga + Gb), here Ga and Gb are glucose concentrations of effluent of channel A and B respectively. A higher penetration rate was obtained when using phosphate buffer (0.01M) as carrier solution instead of using distilled water. Operating pressure differences, temperature and residential time affected glucose penetration. Under the condition of 0.02MPa pressure differences and 0.23 min of residential time (12.8ml/L), Rp was about 12% in the range of 10-70mM with CV < 4%. When sample stream was yeast broth, the glucose penetration rate Rp was stable for at least 48 hr. Good relationship was observed between on-line and off-line sampling for glucose determination in yeast fermentation, the correlation coefficient r was 0.985.