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Journal ArticleDOI

The productivity of two serial chemostats

28 Oct 2022-International Journal of Biomathematics (International Journal of Biomathematics)-Vol. 16, Iss: 06
TL;DR: In this paper , the authors considered the production of biomass of two interconnected chemostats in series with biomass mortality and a growth kinetic of the biomass described by an increasing function, and compared the productivity of a single chemostat with the same mortality rate and with volume equal to the sum of the volumes of the two Chemostats.
Abstract: This paper considers the production of biomass of two interconnected chemostats in series with biomass mortality and a growth kinetic of the biomass described by an increasing function. A comparison is made with the productivity of a single chemostat with the same mortality rate and with volume equal to the sum of the volumes of the two chemostats. We determine the operating conditions under which the productivity of the serial configuration is greater than the productivity of the single chemostat. Moreover, the differences and similarities in the results corresponding to the case with mortality and the one without mortality, are highlighted. The mortality leads to surprising results where the productivity of a steady state where the bacteria are washed out in the first chemostat is greater than the one where the bacteria are present in both chemostats.

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TL;DR: In this paper , the authors considered the model of two chemostats in series when a biomass mortality is considered in each vessel and compared the performance of the serial configuration with a single chemostat with the same total volume.

2 citations

References
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Journal ArticleDOI
TL;DR: It is concluded that continuous culture may usually be expected to show a five to tenfold increase in output as compared with a batch process.
Abstract: SUMMARY: A theoretical treatment of continuous culture is given, which allows quantitative prediction of the steady-state concentrations of bacteria and substrate in the culture, and how these may be expected to vary with change of medium, concentration and flow-rate. The layout and operation of a small pilot plant for the continuous culture of bacteria are described. This plant has been operated continuously for periods of up to 4 months without breakdown or contamination of the culture. No alterations in the properties of the organisms studied have occurred during such periods of continuous culture. Results are given of a series of experiments on the continuous culture of Aerobacter cloacae in a chemically defined medium, designed to allow quantitative comparison with the results predicted by the theory. The relative advantages of batch and continuous culture as production processes are discussed, and it is concluded that continuous culture may usually be expected to show a five to tenfold increase in output as compared with a batch process.

974 citations

Journal ArticleDOI
TL;DR: A simple adaptive control algorithm, for which theoretical stability and convergence properties had been previously demonstrated, has been successfully implemented on a biomethanation pilot reactor.
Abstract: A simple adaptive control algorithm, for which theoretical stability and convergence properties had been previously demonstrated, has been successfully implemented on a biomethanation pilot reactor. The methane digester, operated in the CSTR mode was submitted to a shock load, and successfully computer controlled during the subsequent transitory state.

84 citations

Journal ArticleDOI
TL;DR: In this article, an equation is derived to predict the minimum possible total residence time to achieve any desired substrate conversion, which is applied to Monod, substrate inhibition and product inhibition cases.
Abstract: The primary reactor type currently used in the production of microorganisms or microbial products is the stirred tank reactor (STR). If operated on a continuous flow basis (CFSTR) they become similar in performance to the primary reactor configuration used in most of the chemical industry. In this work, microbial kinetics are considered in the design of CFSTRs in series. An equation is derived to predict the minimum possible total residence time to achieve any desired substrate conversion. The equation permits the use of a wide variety of growth kinetic models and is applied here to Monod, substrate inhibition and product inhibition cases. For the majority of cases, it is found that three optimally designed CFSTRs in series provide close to the minimum possible residence time for any desired substrate conversion. A comparison to the use of a PFR is made for cases of both no-recycle and biomass recycle to the CFSTR train. It is found that three CFSTRs, which are not equi-volume, provide the same required total mean residence time as a PFR for Monod kinetics, but are significantly superior (i.e., less total volume required) to a PFR for substrate-inhibited growth. Le type de reacteur primaire habituellement utilise dans la production de microorganismes ou de produits microbiens est le reacteur agite (STR). En mode continu (CFSTR), la performance de ces reacteurs se compare a celle des reacteurs primaires utilises le plus souvent dans l'industrie chimique. On considere dans ce travail des cinetiques microbiennes pour la conception de reacteurs agites continus en serie. Une equation est etablie pour predire le temps de sejour total possible minimum pour obtenir les conversions voulues de substrat. Cette equation permet l'utilisation d'un large eventail de modeles cinetiques de croissance et est appliquee ici aux cas de Monod, de l'inhibition de substrat et de l'inhibition de produit. Dans la majorite des cas, on a trouve que trois reacteurs agites continus en serie concus de maniere optimale permettent de se rapprocher du temps de sejour possible minimum pour toute conversion de substrat desiree. On a effectue une comparaison entre ce type de reacteur et un PFR pour les cas d'un non-recyclage et d'un recyclage de biomasse dans la serie de reacteurs agites continus. On a trouve que trois reacteurs agites continus, qui n'ont pas le měme volume, donnent le měme temps de sejour moyen total requis qu'un PFR pour la cinetique de Monod, mais ils sont nettement plus performants (par exemple volume total requis moins important) que les PFR pour la croissance inhibee par le substrat.

64 citations

Journal ArticleDOI
TL;DR: Herbert, D. as discussed by the authors argued that if one fermenter gives good results, two fermenters will give better results and three fermenters better still, and this is sometimes true, but often false.

64 citations

Journal ArticleDOI
TL;DR: In this paper, the current state of mathematical modelling in microbial ecology, looking back at the developments that have defined the synergies between the disciplines, and outline some of the existing challenges that motivate us to provide practical models in the hope that greater engagement with empiricists and practitioners in the microbiological domain may be achieved.

60 citations