Teixeira and Mota (1990) proposed a membrane bioreactor for the assessment of
internal diffusion limitations in yeast flocs (Figure 13.4). In this case a diffusion-reaction
model (the first approach) was used and the authors found decreases in specific lactose
uptake rate of flocculating K. marxianus, when compared with non-flocculating cells.
This being so, the ratio between the specific lactose uptake rates of the flocculating strain
over the non-flocculating strain (i.e., an effectiveness factor—η) could be calculated and
its
Figure 13.3 Experimental set-up: (1)
isolated measuring chamber (isolation
not shown); (2) reservior; (3) DO 2
probe; (4) stainless steel mesh; (5a,b)
magnetic rod; (6) rubber sealing plug;
(7) gas sparger; (8) temperature control
jacket; (9a, b) and (10a-e) one-way-
valves; (11)two-way valve; (12a, b)
circulating temperature control liquid;
(13) thermometer; (14) rubber sealing
O-ring.
Flocculation bioreactors 401