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Unstable steady state operations of substrate inhibited cultures by dissolved oxygen control

Paper ID Volume ID Publish Year Pages File Format Full-Text
23810 43474 2011 7 PDF Available
Title
Unstable steady state operations of substrate inhibited cultures by dissolved oxygen control
Abstract

Microorganism kinetic growth characterized by substrate inhibition was investigated by means of a continuous stirred tank reactor equipped with a feedback controller of the medium feeding flow rate. The aerobic growth of Pseudomonas sp. OX1 with phenol as carbon/energy source was adopted as a case study to test a new control strategy using dissolved oxygen concentration as a state variable. The controller was successful in steadily operating bioconversion under intrinsically unstable conditions. A simple model of the controlled system was proposed to set the feedback controller.The specific growth rate of Pseudomonas sp. OX1 was successfully described by means of the Haldane model. The regression of the experimental data yielded μM = 0.26 h−1, KPh = 5 × 10−3 g/L and KI = 0.2 g/L. The biomass-to-substrate fractional yield as a function of the specific growth rate did not change moving from substrate-inhibited to substrate-deficient state. The data was modelled according to the Pirt model: m = 1.7 × 10−2 g/(g h), YX/PhTh=1.3 g/g. The specific growth rates calculated for batch and continuous growth were compared.

► Microorganism kinetic growth characterized by substrate inhibition was investigated. ► A CSTR equipped with a feedback controller of the medium feeding flow rate was adopted. ► A control strategy using dissolved O2 concentration as a state variable was adopted. ► The specific growth rate was successfully described by means of the Haldane model. ► The specific growth rates calculated for batch and continuous growth were compared.

Keywords
Unstable steady state; Substrate inhibition; Feedback control
First Page Preview
Unstable steady state operations of substrate inhibited cultures by dissolved oxygen control
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 156, Issue 4, 20 December 2011, Pages 302–308
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering