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September 2013 Stochastic models for a chemostat and long-time behavior
Pierre Collet, Servet Martínez, Sylvie Méléard, Jaime San Martín
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Adv. in Appl. Probab. 45(3): 822-837 (September 2013). DOI: 10.1239/aap/1377868540


We introduce two stochastic chemostat models consisting of a coupled population-nutrient process reflecting the interaction between the nutrient and the bacteria in the chemostat with finite volume. The nutrient concentration evolves continuously but depends on the population size, while the population size is a birth-and-death process with coefficients depending on time through the nutrient concentration. The nutrient is shared by the bacteria and creates a regulation of the bacterial population size. The latter and the fluctuations due to the random births and deaths of individuals make the population go almost surely to extinction. Therefore, we are interested in the long-time behavior of the bacterial population conditioned to non-extinction. We prove the global existence of the process and its almost-sure extinction. The existence of quasi-stationary distributions is obtained based on a general fixed-point argument. Moreover, we prove the absolute continuity of the nutrient distribution when conditioned to a fixed number of individuals and the smoothness of the corresponding densities.


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Pierre Collet. Servet Martínez. Sylvie Méléard. Jaime San Martín. "Stochastic models for a chemostat and long-time behavior." Adv. in Appl. Probab. 45 (3) 822 - 837, September 2013.


Published: September 2013
First available in Project Euclid: 30 August 2013

zbMATH: 1274.60239
MathSciNet: MR3102473
Digital Object Identifier: 10.1239/aap/1377868540

Primary: 60J25, 60J27, 92D25

Rights: Copyright © 2013 Applied Probability Trust


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Vol.45 • No. 3 • September 2013
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