We show that for certain configurations of two chemostats fed in parallel, the presence of two different species in each tank can improve the yield of the whole process, compared to the same configuration having the same species in each volume. This leads to a (so-called) “transgressive over-yielding” due to spatialization. Key-words. Chemostat, steady-state, optimization, over-yielding.

Molar growth yields were determined from chemostat cultures of Hydrogenomonas eutropha on succinate and on fumarate. The yields from culture on succinate were about 12 g higher than on fumarate. Assuming this difference to be equivalent to 1 molecule of adenosine triphosphate, it is concluded that the oxidation by oxygen of the Hydrogenomonas cytochrome b yields 1 molecule of adenosine triphosp...

Short-term labeling with radioactive thymidine led to inaccurate estimates of deoxyribonucleic acid synthesis at some growth rates in steady-state cultures of Escherichia coli B/r. Estimates were corrected in chemostat cultures by adding adenosine, a known inhibitor of thymidine phosphorylase.

A teflon chemostat constructed for studies of microbial trace metal metabolism is described. The utility of this continuous culture system was demonstrated with Streptococcus mutans, in which iron and manganese stimulated growth in ranges of 0.18 to 0.45 and 18 to 54 microM, respectively. This device should facilitate studies of the effect of trace metals on a variety of physiological functions.