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Feeding Strategies Based on Probing Control for E. coli and V. cholerae Cultivations

de Maré, Lena LU (2006) In PhD Thesis TFRT-1076
Abstract
The recombinant DNA techniques have made it possible to produce many different proteins for a wide range of applications. The vector encoding for the recombinant protein is often inserted in the bacterium E. coli as it is a well studied and a well-known organism. To achieve a high productivity, it is important to reach a high cell density. This is obtained through fed-batch operation where the nutrient, usually glucose, is added continuously. The feeding strategy should be designed to avoid starvation and overfeeding. This is not an easy task as on-line measurements of key variables are normally not available. A probing feeding strategy using the measurements of the standard dissolved oxygen sensor is developed by M. Åkesson. The key idea... (More)
The recombinant DNA techniques have made it possible to produce many different proteins for a wide range of applications. The vector encoding for the recombinant protein is often inserted in the bacterium E. coli as it is a well studied and a well-known organism. To achieve a high productivity, it is important to reach a high cell density. This is obtained through fed-batch operation where the nutrient, usually glucose, is added continuously. The feeding strategy should be designed to avoid starvation and overfeeding. This is not an easy task as on-line measurements of key variables are normally not available. A probing feeding strategy using the measurements of the standard dissolved oxygen sensor is developed by M. Åkesson. The key idea is to superimpose pulses on the feed-rate and make use of the responses in the dissolved oxygen in a feedback algorithm. Also, when the maximum transfer capacity of the reactor is reached the feed-rate is decreased in order to keep the reactor working under aerobic conditions. The strategy has been successfully implemented in cultivations with different E. coli strains and on different scales.



The probing feeding strategy is further developed in many aspects in this thesis. Firstly, it is implemented with good results also in V. cholerae cultivations, which shows how general the strategy is. Also, a model of a bio-reactor operating in fed-batch mode is presented and verified. The effect on the tuning rules of the probing controller is investigated.



The probing feeding strategy is further improved for a more efficient product synthesis. This new fermentation technique manipulates the temperature when the maximum oxygen transfer capacity of the reactor is reached. The strategy consists of a mid-ranging controller structure and a modified probing controller. It is analysed and evaluated in experiments and simulations.



Furthermore, some E. coli production strains need additions of amino acids or complex media besides the carbon nutrient to grow and produce the recombinant protein. The probing control concept is therefore extended in order to handle these situations. Feeding strategies for dual feeding of amino acids or complex media and glucose are developed. (Less)
Abstract (Swedish)
Popular Abstract in Swedish

Många olika proteiner kan produceras med hjälp av rekombinanta DNA tekniker. Ofta sätts vektorn som kodar för det rekombinanta proteinet in i bakterien E. coli, då den är välkänd. Det är viktigt att producera mycket celler för att uppnå hög produktivitet. Detta görs genom att näringsämnet (ofta glukos) tillsätts kontinuerligt till en så kallad semisats reaktor. Tillsatsen bör ske så att svält och överflöd undviks. Detta är inte lätt då nyckelvariablerna vanligtvis är svåra att mäta kontinuerligt. M. Åkesson har utvecklat en strategi baserad på givaren som mäter löst syre. Idéen är att överlagra pulser på tillsatsen och att använda pulssvaren i löst syre i en återkopplingsalgoritm.... (More)
Popular Abstract in Swedish

Många olika proteiner kan produceras med hjälp av rekombinanta DNA tekniker. Ofta sätts vektorn som kodar för det rekombinanta proteinet in i bakterien E. coli, då den är välkänd. Det är viktigt att producera mycket celler för att uppnå hög produktivitet. Detta görs genom att näringsämnet (ofta glukos) tillsätts kontinuerligt till en så kallad semisats reaktor. Tillsatsen bör ske så att svält och överflöd undviks. Detta är inte lätt då nyckelvariablerna vanligtvis är svåra att mäta kontinuerligt. M. Åkesson har utvecklat en strategi baserad på givaren som mäter löst syre. Idéen är att överlagra pulser på tillsatsen och att använda pulssvaren i löst syre i en återkopplingsalgoritm. Tillsättningshastigheten minskas då reaktorns maximala syreöverföringsförmåga nås för att syrenivån i reaktorn inte ska bli allför låg. Strategin har framgångsrikt använts i odlingar i olika skalor och för olika E. coli stammar.



I avhandlingen är tillsättningstrategin utvecklad inom ett flertal områden. Strategin är även använd i odlingar med bakterien V. cholerae, vilket visar strategins allmängiltighet. Dessutom presenteras och verifieras en modell över en semisatsbioreaktor. Modellens påverkan på inställningen av tillsattsregulatorn undersöks också.



Strategin förbättras ytterligare för att öka produktiviten. Denna nya odlingstrategin ändrar på temperaturen då reaktorns maximala syreöverföringskapacitet har nåtts och består bl. a av en ``mid-ranging''-regulatorstruktur. I experiment och simuleringar analyseras och utvärderas strategin. Risken för svält har minskat väsentligt.



Vissa E. coli stammar behöver tillsatts av aminosyror eller komplext medium vid sidan av näringsämnet för att växa och producera det rekombinanta proteinet. Därför utvecklades den ursprungliga strategin dessutom för tillsatts av aminsyror eller komplext medium tillsammans med glukos. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Jacobsen, Elling, School of Electrical Engineering, Automatic Control, Royal Institute of Technology, Stockholm
organization
publishing date
type
Thesis
publication status
published
subject
keywords
robotics, control engineering, Automatiska system, robotteknik, reglerteknik, Automation, Temperature, Mid-ranging control, Amino acid, Complex media, Fed-batch bioreactors, Probing control, Biotechnology, Bioteknik, Parameter estimation, Feeding strategies
in
PhD Thesis TFRT-1076
pages
168 pages
publisher
Department of Automatic Control, Lund Institute of Technology, Lund University
defense location
Room M:B, M-building, Ole Römers väg 1, Faculty of Engineering, Lund University
defense date
2006-06-16 13:15:00
ISSN
0280-5316
0280-5316
language
English
LU publication?
yes
id
80b3c420-27a3-4aba-a55b-424a51f63a09 (old id 546988)
date added to LUP
2016-04-01 15:56:49
date last changed
2019-05-23 15:56:57
@phdthesis{80b3c420-27a3-4aba-a55b-424a51f63a09,
  abstract     = {The recombinant DNA techniques have made it possible to produce many different proteins for a wide range of applications. The vector encoding for the recombinant protein is often inserted in the bacterium E. coli as it is a well studied and a well-known organism. To achieve a high productivity, it is important to reach a high cell density. This is obtained through fed-batch operation where the nutrient, usually glucose, is added continuously. The feeding strategy should be designed to avoid starvation and overfeeding. This is not an easy task as on-line measurements of key variables are normally not available. A probing feeding strategy using the measurements of the standard dissolved oxygen sensor is developed by M. Åkesson. The key idea is to superimpose pulses on the feed-rate and make use of the responses in the dissolved oxygen in a feedback algorithm. Also, when the maximum transfer capacity of the reactor is reached the feed-rate is decreased in order to keep the reactor working under aerobic conditions. The strategy has been successfully implemented in cultivations with different E. coli strains and on different scales.<br/><br>
<br/><br>
The probing feeding strategy is further developed in many aspects in this thesis. Firstly, it is implemented with good results also in V. cholerae cultivations, which shows how general the strategy is. Also, a model of a bio-reactor operating in fed-batch mode is presented and verified. The effect on the tuning rules of the probing controller is investigated.<br/><br>
<br/><br>
The probing feeding strategy is further improved for a more efficient product synthesis. This new fermentation technique manipulates the temperature when the maximum oxygen transfer capacity of the reactor is reached. The strategy consists of a mid-ranging controller structure and a modified probing controller. It is analysed and evaluated in experiments and simulations.<br/><br>
<br/><br>
Furthermore, some E. coli production strains need additions of amino acids or complex media besides the carbon nutrient to grow and produce the recombinant protein. The probing control concept is therefore extended in order to handle these situations. Feeding strategies for dual feeding of amino acids or complex media and glucose are developed.},
  author       = {de Maré, Lena},
  issn         = {0280-5316},
  language     = {eng},
  publisher    = {Department of Automatic Control, Lund Institute of Technology, Lund University},
  school       = {Lund University},
  series       = {PhD Thesis TFRT-1076},
  title        = {Feeding Strategies Based on Probing Control for E. coli and V. cholerae Cultivations},
  url          = {https://lup.lub.lu.se/search/files/4521982/546989.pdf},
  year         = {2006},
}