DETERMINATION OF THE K-S VALUES DURING THE GROWTH OF ALCALIGENES-EUTROPHUS ON PHENOL, 2,4-DICHLOROPHENOXYACETIC ACID AND FRUCTOSE

The determination of the K-S values presented here is based on the est imation of the stationary substrate concentrations in continuous culti vation experiments. The separation of biomass from the suspension was performed by an ultrafiltration step which succeeded within one second . The decay of substrate concentration during sampling was calculated to amount to less than 6% of the stationary substrate concentration at relevant growth rates. The K-S values derived from these reduced subs trate concentrations deviated by only 10% from the theoretical values at a biomass concentration of about 1 g/l. Thus relevant kinetic param eters can be calculated from the data obtained by this procedure. Valu es of 11, 59 and 14 mu M were obtained with 2,4-dichlorophenoxyacetic acid (2,4-D), phenol and fructose, respectively. Similar K-S values we re derived with 2,4-D and fructose by using a respiration-based determ ination for reasons of comparison. With phenol this value was only 7 m u M which is ascribed to a physiological background.