Figure 4

Representative experiments (conducted in duplicate) showing production of organic compounds and dry cell mass during the aerobic and oxygen limited lactate fermentation by E. coli B0013-090B3 in a 25-l bioreactor. The dotted line indicates the time when the culture was shifted from the aerobic cultivation to the oxygen limited production phase. Additions of glucose of 136.2, 136.2, 150.9 and 136.2 g were made to the bioreactor during the production phase. Open triangle: dry cell mass, closed square: lactate, open square: pyruvate, open diamond: acetate; open circle: glucose concentration. (a) The aerobic cultivation was carried out at 37°C with dissolved oxygen greater than 30% saturation by supplying 3–7 l/min air and 200–1000 rpm of agitation. The production phase was done at 37°C with 100 rpm of agitation and without aeration. (b) The aerobic cultivation was carried out at 37°C with dissolved oxygen higher than 30% saturation by supplying 3–7 l/min air and 200–1000 rpm of agitation. The production phase was done at 42°C with 100 rpm of agitation and without aeration.