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11.
Dynamical behavior of a stochastic food chain chemostat model with Monod response functions
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Miaomao Gao Daqing Jiang Kai Qi Tasawar Hayat Ahmed Alsaedi Bashir Ahmad 《Journal of Applied Analysis & Computation》2019,9(6):2278-2294
This paper studies a food chain chemostat model with Monod response functions, which is perturbed by white noise. Firstly, we prove the existence and uniqueness of the global positive solution. Then sufficient conditions for the existence of a unique ergodic stationary distribution are established by constructing suitable Lyapunov functions. Moreover, we consider the extinction of microbes in two cases. In the first case, both the predator and prey species are extinct. In the second case, only the predator species is extinct, and the prey species survives. Finally, numerical simulations are carried out to illustrate the theoretical results. 相似文献
12.
Global dynamics analysis of a nonlinear impulsive stochastic chemostat system in a polluted environment
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This paper intends to develop a new method to obtain the threshold of an impulsive stochastic chemostat model with saturated growth rate in a polluted environment. By using the theory of impulsive differential equations and stochastic differential equations, we obtain conditions for the extinction and the permanence of the microorganisms of the deterministic chemostat model and the stochastic chemostat model. We develop a new numerical computation method for impulsive stochastic differential system to simulate and illustrate our theoretical conclusions. The biological results show that a small stochastic disturbance can cause the microorganism to die out, that is, a permanent deterministic system can go to extinction under the white noise stochastic disturbance. The theoretical method can also be used to explore the threshold of some impulsive stochastic differential equations. 相似文献
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Intraguild predation is added to a mathematical model of competition between two species for a single nutrient with internal storage in the unstirred chemostat. At first, we established the sharp a priori estimates for nonnegative solutions of the system, which assure that all of nonnegative solutions belong to a special cone. The selection of this special cone enables us to apply the topological fixed point theorems in cones to establish the existence of positive solutions. Secondly, existence for positive steady state solutions of intraguild prey and intraguild predator is established in terms of the principal eigenvalues of associated nonlinear eigenvalue problems by means of the degree theory in the special cone. It turns out that positive steady state solutions exist when the associated principal eigenvalues are both negative or both positive. 相似文献
15.
In this paper, based on the existing literature, we further study an important statistical character of a stochastic delayed chemostat model. By constructing suitable Lyapunov functional and using the stochastic Lyapunov analysis method, we investigate the existence of stationary distribution and the ergodicity of a stochastic delayed chemostat model, which can help us better understand the dynamic behavior and statistical characteristics of stochastic delayed biological models. 相似文献
16.
Alexander S. Fedorov Sergey Kosourov Maria L. Ghirardi Michael Seibert 《Applied biochemistry and biotechnology》2005,121(1-3):403-412
This study demonstrates, for the first time, that it is possible to couple sulfate-limited Chlamydomonas reinhardtii growth to continuous H2 photoproduction for more than 4000 h. A two-stage chemostat system physically separates photosynthetic growth from H2 production, and it incorporates two automated photobioreactors (PhBRs). In the first PhBR, the algal cultures are grown aerobically
in chemostat mode under limited sulfate to obtain photosynthetically competent cells. Active cells are then continuously delivered
to the second PhBR, where H2 production occurs under anaerobic conditions. The dependence of the H2 production rate on sulfate concentration in the medium, dilution rates in the PhBRs, and incident light intensity is reported. 相似文献
17.
In this paper, we introduce and study a model of a predator-prey system with Monod type functional response under periodic
pulsed chemostat conditions, which contains with predator, prey, and periodically pulsed substrate. We investigate the subsystem
with substrate and prey and study the stability of the periodic solutions, which are the boundary periodic solutions of the
system. The stability analysis of the boundary periodic solution yields an invasion threshold. By use of standard techniques
of bifurcation theory, we prove that above this threshold there are periodic oscillations in substrate, prey and predator.
Simple cycles may give way to chaos in a cascade of period-doubling bifurcations. Furthermore, by comparing bifurcation diagrams
with different bifurcation parameters, we can see that the impulsive system shows two kinds of bifurcations, whose are period-doubling
and period-halfing. 相似文献
18.
Global qualitative analysis of new Monod type chemostat model with delayed growth response and pulsed input in polluted environment 总被引:1,自引:0,他引:1
In this paper, we consider a new Monod type chemostat model with time delay and impulsive input concentration of the nutrient in a polluted environment. Using the discrete dynamical system determined by the stroboscopic map, we obtain a "microorganism-extinction" periodic solution. Further, we establish the sufficient conditions for the global attractivity of the microorganism-extinction periodic solution. Using new computational techniques for impulsive and delayed differential equation, we prove that the system is permanent under appropriate conditions. Our results show that time delay is "profitless". 相似文献
19.
Grethlein A. J. Worden R. M. Jain M. K. Datta R. 《Applied biochemistry and biotechnology》1990,(1):875-884
Continuous, steady-state fermentations using carbon monoxide gas as the sole carbon and energy source have been achieved with
the CO strain ofButyribacterium methylotrophicum. Fermentation pH was found to regulate carbon monoxide metabolism over the pH range of 6.8 to 5.0. Cell growth diminished
at low pH, with washout occurring at pH 5.0. As observed previously in batch culture, lower pH values favored production of
butyrate over acetate. The mechanism responsible for this trend is currently being investigated by quantification of key intracellular
enzyme activities.
At low pH values, direct, steady-state fermentation of carbon monoxide to alcohols has been verified. Of major significance
is the production of butanol from carbon monoxide in pure culture. This newly identified pathway provides a potential mechanism
for direct bioconversion of synthesis gas to butanol. 相似文献
20.
The cybernetic approach to modeling of microbial kinetics in a mixedsubstrate environment has been used in this work for the
fermentative production of ethanol from cheese whey. In this system, the cells grow on multiple substrates and generate metabolic
energy during product formation. This article deals with the development of a mathematical model in which the concept of cell
maintenance was modified in light of the specific nature of product formation. Continuous culture data for anaerobic production
of ethanol byKluyveromyces marxianus CBS 397 on glucose and lactose were used to estimate the kinetic parameters for subsequent use in predicting the behavior
of microbial growth and product formation in new situations. 相似文献