Feedback Control of a Recirculating Bioreactor with Electrophoretic Removal of Inhibitory Extracellular DNA

TL;DR

This paper develops a feedback control system for a recirculating bioreactor with electrophoretic DNA removal, improving microbial productivity and profit through advanced control strategies.

Contribution

It introduces a novel control framework combining online estimation with adaptive and simple control strategies for DNA removal in bioreactors.

Findings

MPC strategy outperforms bang-bang control in profit and DNA regulation.

Closed-loop simulations demonstrate robustness under various conditions.

Adaptive control maintains DNA levels below inhibition thresholds.

Abstract

Extracellular DNA accumulation in recirculating bioprocesses inhibits microbial growth and reduces productivity. We consider a continuous bioreactor with a recirculating loop and an electrophoretic filtration unit for selective DNA removal, and develop a feedback control framework combining online state and parameter estimation via an Unscented Kalman Filter with two control strategies: an adaptive Model Predictive Controller that jointly optimizes dilution rate and filtration activation, and a simpler bang--bang filtration policy with lookup-table dilution rate selection. Closed-loop simulations under nominal and perturbed conditions show that the MPC strategy achieves significantly higher cumulative profit while keeping DNA concentration below the inhibition threshold.