Rich dynamics of a three-tiered anaerobic food-web in a chemostat with multiple substrate inflow

The mathematical analysis of a three-tiered food-web describing anaerobic chlorophenol mineralisation has suggested the emergence of interesting dynamical behaviour through its specific ecological interactions, which include competition, syntrophy, and product inhibition. Previous numerical analyses have revealed the possibility of a Hopf bifurcation at the interior equilibrium as well as the role of extraneous substrate inputs in both mitigating the emergence of periodic solutions and expanding the desired operating region where the positive steady-state is stable and full mineralisation occurs. Here we show that, for a generalised model, the inflow of multiple substrates results in greater dynamical complexity and show the occurrence of a supercritical Hopf bifurcation resulting from variations in these operating parameters. Further, using numerical estimation, we also show that variations in the dilution rate can lead to Bogdanov-Takens and Bautin bifurcations. Finally, we are able to apply persistence theory for a range of parameter sets to demonstrate persistence in cases where chlorophenol and hydrogen are extraneously added to the system, mirroring recent applied studies highlighting the role of hydrogen in maintaining stable anaerobic microbial communities.