Use of Image Analysis to Understand Enzyme Stability in an Aerated Stirred Reactor

Mafalda Dias Gomes, Rayisa P. Moiseyenko, Andreas Baum, Thomas M. Jørgensen, John M. Woodley*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Efficient regeneration of NAD(P)+ cofactors is essential for large‐scale application of alcohol dehydrogenases due to the high cost and chemical instability of these cofactors. NAD(P)+ can be regenerated effectively using NAD(P)H oxidases that require molecular oxygen as a co‐substrate. In large‐scale biocatalytic processes, agitation and aeration are needed for sufficient oxygen transfer into the liquid phase, both of which have been shown to significantly increase the rate of enzyme deactivation. As such, the aim of this study was to identify the existence of a correlation between enzyme stability and gas‐liquid interfacial area inside the bioreactor. This was done by measuring gas‐liquid interfacial areas inside an aerated stirred reactor, using an in situ optical probe, and simultaneously measuring the kinetic stability of NAD(P)H oxidase. Following enzyme incubation at various power inputs and gas‐phase compositions, the residual activity was assessed and video samples were analysed through an image processing algorithm. Enzyme deactivation was found to be proportional to an increase in interfacial area up to a certain limit, where power input appears to have a higher impact. Furthermore, the presence of oxygen increased enzyme deactivation rates at low interfacial areas. The areas were validated with defined glass beads and found to be in the range of those in large‐scale bioreactors. Finally, a correlation between the enzyme half‐life and specific interfacial area was obtained. Therefore, we conclude that the method developed in this contribution can help to predict the behavior of biocatalyst stability under industrially relevant conditions, concerning specific gas‐liquid interfacial areas.
Original languageEnglish
Article numbere2878
JournalBiotechnology Progress
ISSN8756-7938
DOIs
Publication statusAccepted/In press - 2019

Cite this

@article{eb52033f131e476a949ab711583e7f0c,
title = "Use of Image Analysis to Understand Enzyme Stability in an Aerated Stirred Reactor",
abstract = "Efficient regeneration of NAD(P)+ cofactors is essential for large‐scale application of alcohol dehydrogenases due to the high cost and chemical instability of these cofactors. NAD(P)+ can be regenerated effectively using NAD(P)H oxidases that require molecular oxygen as a co‐substrate. In large‐scale biocatalytic processes, agitation and aeration are needed for sufficient oxygen transfer into the liquid phase, both of which have been shown to significantly increase the rate of enzyme deactivation. As such, the aim of this study was to identify the existence of a correlation between enzyme stability and gas‐liquid interfacial area inside the bioreactor. This was done by measuring gas‐liquid interfacial areas inside an aerated stirred reactor, using an in situ optical probe, and simultaneously measuring the kinetic stability of NAD(P)H oxidase. Following enzyme incubation at various power inputs and gas‐phase compositions, the residual activity was assessed and video samples were analysed through an image processing algorithm. Enzyme deactivation was found to be proportional to an increase in interfacial area up to a certain limit, where power input appears to have a higher impact. Furthermore, the presence of oxygen increased enzyme deactivation rates at low interfacial areas. The areas were validated with defined glass beads and found to be in the range of those in large‐scale bioreactors. Finally, a correlation between the enzyme half‐life and specific interfacial area was obtained. Therefore, we conclude that the method developed in this contribution can help to predict the behavior of biocatalyst stability under industrially relevant conditions, concerning specific gas‐liquid interfacial areas.",
author = "{Dias Gomes}, Mafalda and Moiseyenko, {Rayisa P.} and Andreas Baum and J{\o}rgensen, {Thomas M.} and Woodley, {John M.}",
year = "2019",
doi = "10.1002/btpr.2878",
language = "English",
journal = "Biotechnology Progress",
issn = "8756-7938",
publisher = "Wiley-Blackwell",

}

Use of Image Analysis to Understand Enzyme Stability in an Aerated Stirred Reactor. / Dias Gomes, Mafalda; Moiseyenko, Rayisa P.; Baum, Andreas; Jørgensen, Thomas M.; Woodley, John M.

In: Biotechnology Progress, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Use of Image Analysis to Understand Enzyme Stability in an Aerated Stirred Reactor

AU - Dias Gomes, Mafalda

AU - Moiseyenko, Rayisa P.

AU - Baum, Andreas

AU - Jørgensen, Thomas M.

AU - Woodley, John M.

PY - 2019

Y1 - 2019

N2 - Efficient regeneration of NAD(P)+ cofactors is essential for large‐scale application of alcohol dehydrogenases due to the high cost and chemical instability of these cofactors. NAD(P)+ can be regenerated effectively using NAD(P)H oxidases that require molecular oxygen as a co‐substrate. In large‐scale biocatalytic processes, agitation and aeration are needed for sufficient oxygen transfer into the liquid phase, both of which have been shown to significantly increase the rate of enzyme deactivation. As such, the aim of this study was to identify the existence of a correlation between enzyme stability and gas‐liquid interfacial area inside the bioreactor. This was done by measuring gas‐liquid interfacial areas inside an aerated stirred reactor, using an in situ optical probe, and simultaneously measuring the kinetic stability of NAD(P)H oxidase. Following enzyme incubation at various power inputs and gas‐phase compositions, the residual activity was assessed and video samples were analysed through an image processing algorithm. Enzyme deactivation was found to be proportional to an increase in interfacial area up to a certain limit, where power input appears to have a higher impact. Furthermore, the presence of oxygen increased enzyme deactivation rates at low interfacial areas. The areas were validated with defined glass beads and found to be in the range of those in large‐scale bioreactors. Finally, a correlation between the enzyme half‐life and specific interfacial area was obtained. Therefore, we conclude that the method developed in this contribution can help to predict the behavior of biocatalyst stability under industrially relevant conditions, concerning specific gas‐liquid interfacial areas.

AB - Efficient regeneration of NAD(P)+ cofactors is essential for large‐scale application of alcohol dehydrogenases due to the high cost and chemical instability of these cofactors. NAD(P)+ can be regenerated effectively using NAD(P)H oxidases that require molecular oxygen as a co‐substrate. In large‐scale biocatalytic processes, agitation and aeration are needed for sufficient oxygen transfer into the liquid phase, both of which have been shown to significantly increase the rate of enzyme deactivation. As such, the aim of this study was to identify the existence of a correlation between enzyme stability and gas‐liquid interfacial area inside the bioreactor. This was done by measuring gas‐liquid interfacial areas inside an aerated stirred reactor, using an in situ optical probe, and simultaneously measuring the kinetic stability of NAD(P)H oxidase. Following enzyme incubation at various power inputs and gas‐phase compositions, the residual activity was assessed and video samples were analysed through an image processing algorithm. Enzyme deactivation was found to be proportional to an increase in interfacial area up to a certain limit, where power input appears to have a higher impact. Furthermore, the presence of oxygen increased enzyme deactivation rates at low interfacial areas. The areas were validated with defined glass beads and found to be in the range of those in large‐scale bioreactors. Finally, a correlation between the enzyme half‐life and specific interfacial area was obtained. Therefore, we conclude that the method developed in this contribution can help to predict the behavior of biocatalyst stability under industrially relevant conditions, concerning specific gas‐liquid interfacial areas.

U2 - 10.1002/btpr.2878

DO - 10.1002/btpr.2878

M3 - Journal article

JO - Biotechnology Progress

JF - Biotechnology Progress

SN - 8756-7938

M1 - e2878

ER -