The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Coexistence of three pure and simple competitors in four interconnected bioreactors
Author:	Wu, Ming
View Online:	njit-etd1991-066 ([v], [74] pages ~ 1.9 MB pdf)
Department:	Department of Chemical Engineering, Chemistry and Environmental Science
Degree:	Master of Science
Program:	Chemical Engineering
Document Type:	Thesis
Advisory Committee:	Baltzis, Basil (Committee chair) Lewandowski, Gordon (Committee member) Knox, Dana E. (Committee member)
Date:	1991
Keywords:	Microbial growth -- Computer simulation Bioreactors -- Computer simulation
Availability:	Unrestricted
Abstract:	It is known that a homogeneous environment having invariant inputs cannot allow for steady state coexistence of any number of pure and simple competitors. However, it has been proven that two pure and simple competitors can coexist at a steady state in two interconnected chemostats, if the conditions are such that they allow a differ-ent species to grow faster in each one of the two vessels. It has been also shown that three pure and simple competitors cannot coexist in three interconnected chemostats, even if the conditions are such that a different population could grow faster (have the competitive advantage) in each chemostat. The present study investigates theoretically whether the spatial heterogeneities created by four interconnected chemostats may lead to coexistence of three pure and simple competitors. Computer simulations indicate that there is the domain of coexistence of three species (XYZ) between do-mains of coexistence of two species. If the XYZ domain is between an XY and a YZ region, species Y grows faster than X and Z in two out of the four chemostats, for parameter values leading to XYZ coexistence. It is then concluded that spatial heterogeneities can lead to steady state coexistence of three pure and simple com-petitors. It is also concluded that N pure and simple competitors cannot coexist in N interconnected reactors; hut one could speculate that if there are N competitors, in order for them to coexist in an environment, this environment must be comprised of two subenvironments each one of which, should be able to maintain N-1 species. In configurations of chemostats then, it seems that one needs 2N-1 vessels. This is a necessary but not sufficient condition. The results for the three species system, are presented in two-dimensional operating diagrams and the effect of parameters on the behavior of the system, is studied to a certain extent.