Developing Lotka–Volterra Based Models to Describe Bdellovibrio Predation in a Batch and Chemostat Experimental System

Abstract

The application of Bdellovibrio predatory bacteria as an antibiotic alternative is hindered by the lack of experimentally validated models. To address this, we use flow cytometry as a high-throughput method to accurately quantify Bdellovibrio bacterivorous and Pseudomonas sp. prey growth in batch culture, enabling the determination of key growth parameters. We then develop Lotka–Volterra based predator–prey mathematical models with Holling type II and Holling type III dynamics, incorporating glucose as the prey substrate. We conduct experiments in batch and chemostat cultures to evaluate the ability of the model to predict B. bacterivorous predation. In batch systems, B. bacteriovorus dynamics can be captured by the Holling type III numerical response (distance correlation = 0.999), which supports the hypothesis of premature prey lysis at high predator–prey ratios. Using chemostat simulations, we identify parameter regimes leading to predator washout, stable coexistence, or predator–prey oscillations. We evaluate this by inducing an experimental realisation of sustained predator–prey oscillations in a chemostat. This is a key phenomenon necessary for self-sustaining biocontrol. Our findings provide a quantitative foundation for optimising B. bacteriovorus applications as a biocontrol agent across diverse fields, including clinical therapy, agriculture, and water treatment.