K. Kovarova et al., CULTIVATION OF ESCHERICHIA-COLI WITH MIXTURES OF 3-PHENYLPROPIONIC ACID AND GLUCOSE - DYNAMICS OF GROWTH AND SUBSTRATE CONSUMPTION, Biodegradation, 7(6), 1997, pp. 445-453
In technical as well as natural ecosystems, pollutants are often miner
alised in the presence of easily degradable carbon sources. A laborato
ry model system consisting of Escherichia coli ML 30 growing with mixt
ures of 3-phenylpropionic acid (3ppa, 'pollutant') and glucose (easily
degradable substrate) was investigated in batch and carbon-limited co
ntinuous culture. Untypically, a linear growth pattern was observed du
ring batch cultivation with 3ppa as the only carbon/energy source. Whe
n exposed to mixtures of both substrates in batch culture, E. coli uti
lised the two compounds sequentially. However, 3ppa and glucose were c
onsumed simultaneously in continuous culture. Whereas a pulse of exces
s glucose to a batch culture growing with 3ppa led to the repression o
f 3ppa utilisation, an excess of glucose added into continuous culture
did not inhibit the utilisation of 3ppa. During continuous cultivatio
n the 3ppa-degrading enzyme system operated close to saturation.