Oxygen control for an industrial pilot-scale fed-batch filamentous fungal fermentation

Abstract

Industrial filamentous fungal fermentations are typically operated in fed-batch mode. Oxygen control represents an important operational challenge due to the varying biomass concentration. In this study, oxygen control is implemented by manipulating the substrate feed rate, i.e. the rate of oxygen consumption. It turns out that the setpoint for dissolved oxygen represents a trade-off since a low dissolved oxygen value favors productivity but can also induce oxygen limitation. This paper addresses the regulation of dissolved oxygen using a cascade control scheme that incorporates auxiliary measurements to improve the control performance. The computation of an appropriate setpoint profile for dissolved oxygen is solved via process optimization. For that purpose, an existing morphologically structured model is extended to include the effects of both low levels of oxygen on growth and medium rheological properties on oxygen transfer. Experimental results obtained at the industrial pilot-scale level confirm the efficiency of the proposed control strategy but also illustrate the shortcomings of the process model at hand for optimizing the dissolved oxygen setpoints.

IMC Based Controller Design for Integrating Systems with Time Delay

“…There also exists processes such as aerospace control systems, vertical takeoff airplane (Filatov et al [2]), DC motors and high speed disk drives (Liu et al [3]), oxygen control in fed batch filamental fungal fermentation reactors (Bodizs et al [4]) whose dynamics show the characteristics of double integrator types.…”

Effect of oxygen supply on the intracellular flux distribution and a two-stage OUR control strategy for enhancing the yield of sodium gluconate production byAspergillus niger

“…The inlet flow rate was measured, as were the mass fractions of oxygen and carbon dioxide in the inlet and the exhaust gases. By using these quantities and a nitrogen (inert) balance, oxygen uptake rate (OUR) and carbon dioxide evolution rate (CER) and respiratory quotient (RQ) were all calculated in real‐time by computer from the following balance Equations: …”

A Directional Modifier-Adaptation Algorithm for Real-Time Optimization

“…While RTO methods have primarily been developed for the more widespread continuous processes, there is also a significant interest in applying RTO to transient processes, and the process engineering literature is rich with applications to batch and semi-batch chemical processes for fine chemicals (Ruppen et al, 1998;Filippi-Bossy et al, 1989;Ubrich et al, 1999), polymerization (Kadam et al, 2007;François et al, 2004;Zafiriou and Zhu, 1990;Clarke-Pringle and Mac Gregor, 1998), distillation (Welz et al, 2008), crystallization (Fiordalis and Georgakis, 2013), and bio-processes (Visser et al, 2000;Bodizs et al, 2007). A review of RTO for batch processes is given by Bonvin et al (2002).…”