Sensor Systems for Bioprocess Monitoring
(1998)- Abstract
- Two different detection methods for on-line monitoring of substrates and products in ethanol fermentations have been studied. Amperometric biosensors were developed for use as detectors in flow injection or liquid chromatographic (LC) systems. Carbon paste was used as the electrode material and served as the supporting matrix to incorporate the enzymes alcohol oxidase or pyranose oxidase. Hydrogen peroxide produced in the enzymatic conversion of the substrates to these oxidases was further reduced by horseradish peroxidase (HRP) which was also incorporated into the carbon paste. Direct electron transfer between the electrode and the active site of HRP, measured within the optimal potential range for bioelectrochemical measurements (-50 mV... (More)
- Two different detection methods for on-line monitoring of substrates and products in ethanol fermentations have been studied. Amperometric biosensors were developed for use as detectors in flow injection or liquid chromatographic (LC) systems. Carbon paste was used as the electrode material and served as the supporting matrix to incorporate the enzymes alcohol oxidase or pyranose oxidase. Hydrogen peroxide produced in the enzymatic conversion of the substrates to these oxidases was further reduced by horseradish peroxidase (HRP) which was also incorporated into the carbon paste. Direct electron transfer between the electrode and the active site of HRP, measured within the optimal potential range for bioelectrochemical measurements (-50 mV vs. Ag/AgCl) resulted in sensitive and selective detection of ethanol and monosaccharides. The addition of various polyhydric alcohols and polyelectrolytes such as lactitol and polyethylenimine enhanced the performance of the electrodes regarding both sensitivity and stability. The amperometric biosensors were used in an on-line set-up in which microdialysis sampling, LC separation and simultaneous detection of both ethanol and monosaccharides were performed in ethanol fermentations.
The second approach was to analyse the off-gas from the bioreactor with an array of metal oxide semiconductor field effect transistors and semiconducting tin oxide sensors in combination with pattern recognition routines such as principal component analysis (PCA) and artificial neural networks (ANNs). PCA was used to extract important sensor parameters which were subsequently used in training an ANN with data sets obtained during several fermentations. Validation of the ANN on an independent data set indicated that state variables such as ethanol, acetaldehyde, acetic acid, glucose and biomass can be estimated. (Less) - Abstract (Swedish)
- Popular Abstract in Swedish
Olika sätt att mäta substrat (monosackarider) och produkter (främst etanol) vid tillverkning av biobränslet etanol har studerats. Etanoltillverkning sker i en fermentor med hjälp av mikroorganismer som kan omvandla socker. Det är av stort intresse att mäta koncentrationen av produkter och substrat under tillverkningsprocessens gång för att veta om den fortlöper som den ska, när den har tagit slut, ifall att den har avstannat pga något fel, och eventuellt för att styra den. I fermentationsvätskan finns även många andra ämnen och partiklar som kan försvåra analysen, och det är därför viktigt med mätmetoder som selektivt mäter enbart de föreningar av intresse. Två tillvägagångsätt har använts i... (More) - Popular Abstract in Swedish
Olika sätt att mäta substrat (monosackarider) och produkter (främst etanol) vid tillverkning av biobränslet etanol har studerats. Etanoltillverkning sker i en fermentor med hjälp av mikroorganismer som kan omvandla socker. Det är av stort intresse att mäta koncentrationen av produkter och substrat under tillverkningsprocessens gång för att veta om den fortlöper som den ska, när den har tagit slut, ifall att den har avstannat pga något fel, och eventuellt för att styra den. I fermentationsvätskan finns även många andra ämnen och partiklar som kan försvåra analysen, och det är därför viktigt med mätmetoder som selektivt mäter enbart de föreningar av intresse. Två tillvägagångsätt har använts i detta arbete.
Biosensorer i form av elektroder av kolpasta innehållande enzym utveklades för mätning i flödessystem i vätskefas. De enzym som användes har god urskiljningsförmåga mellan olika föreningar, och därmed kunde koncentrationen av etanol bestämmas m h a enzymet alkoholoxidas, och glukos, xylos och galaktos m h a pyranosoxidas. Båda enzym var för sig fungerade i en kopplad enzymreaktion tillsammans med pepparrotsperoxidas (som också tillsattes i kolpastan). I och med en pålagd spänning på arbetselektroden (kolpastaelektroden innehållande enzym) kunde pepparrotsperoxidas utbyta elektroner med elektrodmaterialet och en ström kunde mätas som var i proportion till etanol- eller sockerkoncentrationen. Därmed kunde dessa föreningar kvantifieras utan att andra närvarande ämnen störde analysen.
Vidare användes en elektronisk näsa för bestämning av substrat och produkter. En elektronisk näsa består av en rad olika gassensorer (i detta fall: 10 metall-oxid-halvledare fält-effekt-transistorer, 4 tennoxid-baserade sensorer och en optisk koldioxiddetektor) som tillsammans med mönsterigenkänningstekniker kan användas för att bestämma klasser, koncentrationer, mm. Gasfasen ovanför fermentorn pumpades förbi gassensorerna i tiominuters-intervall. Samtidigt mättes den verkliga koncentrationen av substrat och produkter med andra analysmetoder som jämförelse. Responsen från gassensorerna erhållna från flera fermentationer användes för att träna artificiella neurala nätverk för kvantifiering av etanol, glukos, acetat, acetaldehyd, glycerol och biomassa. Dessa validerades på ett oberoende data set (dvs ännu en fermentation) och kunde bestämmas med en noggrannhet på mellan 1.7 och 10%. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/38625
- author
- Lidén, Helena LU
- supervisor
- opponent
-
- Prof Kauffmann, Jean-Michel, Free University of Brussels, Belgium
- organization
- publishing date
- 1998
- type
- Thesis
- publication status
- published
- subject
- keywords
- on-line, pattern recognition, gas sensor array, electronic nose, monosaccharides, ethanol, biosensor, carbon paste electrode, Analytical chemistry, Analytisk kemi
- pages
- 170 pages
- publisher
- Analytical Chemistry, Lund University
- defense location
- Chemical Centre, Lecture hall B, Lund University
- defense date
- 1998-05-20 10:15:00
- external identifiers
-
- other:ISRN: LUNKDL/NKAK--98/1041--SE
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Analytical Chemistry (S/LTH) (011001004)
- id
- 20ba36e6-d54a-4b00-9eb4-ac8fee29e2a4 (old id 38625)
- date added to LUP
- 2016-04-04 12:24:02
- date last changed
- 2018-11-21 21:10:44
@phdthesis{20ba36e6-d54a-4b00-9eb4-ac8fee29e2a4,
abstract = {{Two different detection methods for on-line monitoring of substrates and products in ethanol fermentations have been studied. Amperometric biosensors were developed for use as detectors in flow injection or liquid chromatographic (LC) systems. Carbon paste was used as the electrode material and served as the supporting matrix to incorporate the enzymes alcohol oxidase or pyranose oxidase. Hydrogen peroxide produced in the enzymatic conversion of the substrates to these oxidases was further reduced by horseradish peroxidase (HRP) which was also incorporated into the carbon paste. Direct electron transfer between the electrode and the active site of HRP, measured within the optimal potential range for bioelectrochemical measurements (-50 mV vs. Ag/AgCl) resulted in sensitive and selective detection of ethanol and monosaccharides. The addition of various polyhydric alcohols and polyelectrolytes such as lactitol and polyethylenimine enhanced the performance of the electrodes regarding both sensitivity and stability. The amperometric biosensors were used in an on-line set-up in which microdialysis sampling, LC separation and simultaneous detection of both ethanol and monosaccharides were performed in ethanol fermentations.<br/><br>
<br/><br>
The second approach was to analyse the off-gas from the bioreactor with an array of metal oxide semiconductor field effect transistors and semiconducting tin oxide sensors in combination with pattern recognition routines such as principal component analysis (PCA) and artificial neural networks (ANNs). PCA was used to extract important sensor parameters which were subsequently used in training an ANN with data sets obtained during several fermentations. Validation of the ANN on an independent data set indicated that state variables such as ethanol, acetaldehyde, acetic acid, glucose and biomass can be estimated.}},
author = {{Lidén, Helena}},
keywords = {{on-line; pattern recognition; gas sensor array; electronic nose; monosaccharides; ethanol; biosensor; carbon paste electrode; Analytical chemistry; Analytisk kemi}},
language = {{eng}},
publisher = {{Analytical Chemistry, Lund University}},
school = {{Lund University}},
title = {{Sensor Systems for Bioprocess Monitoring}},
year = {{1998}},
}