Biocatalyst Engineering: Metabolic Engineering, Kinetic modeling and metagenomics applied to industrial biotechnology
(2010)- Abstract
- Industrial biotechnology has been defined as the use and application of
biotechnology for the sustainable processing and production of chemicals,
materials and fuels. It makes use of biocatalysts such as microbial communities,
whole-cell microorganisms or purified enzymes. Although biocatalysts are
considered advantageous, since they operate under mild conditions regarding
temperature and pH and enable chemo-, regio-, and stereoselective reactions,
their utilization on the industrial scale can be impeded by sub-optimal
performance. The present study was aimed at the improvement of two biocatalytic
processes: whole-cell bioreduction for the production of optically... (More) - Industrial biotechnology has been defined as the use and application of
biotechnology for the sustainable processing and production of chemicals,
materials and fuels. It makes use of biocatalysts such as microbial communities,
whole-cell microorganisms or purified enzymes. Although biocatalysts are
considered advantageous, since they operate under mild conditions regarding
temperature and pH and enable chemo-, regio-, and stereoselective reactions,
their utilization on the industrial scale can be impeded by sub-optimal
performance. The present study was aimed at the improvement of two biocatalytic
processes: whole-cell bioreduction for the production of optically pure
alcohols, and ethanol production from lignocellulosic feedstock.
The reduction of the bicyclic diketone, bicyclo[2.2.2]octane-2,6-dione into
1R,4S,6S-6-hydroxy-bicyclo[2.2.2]octane-2-one (endo-alcohol) and 1S,4R,6S-6-
hydroxy-bicyclo[2.2.2]octane-2-one (exo-alcohol) was used as a model bioreduction
reaction. The identification and overexpression of an exo-reductase
encoding gene in Candida tropicalis enabled the production of the uncommon
exo-alcohol as major product. In parallel, the advantages and disadvantages of
metabolically engineered Saccharomyces cerevisiae and Escherichia coli as host
for whole-cell bioreduction were compared for the production of the endoalcohol.
Both these microorganisms gave about the same product purity. While
E. coli showed a three times higher reduction rate, higher cell viability was
maintained during the bioreductions with recombinant S. cerevisiae, which
resulted in higher final conversion (95%) and indicated that yeast could be
recycled.
Improvement of bioethanol production from xylose was achieved through the
construction and use of a kinetic model as a simulation tool for metabolic
engineering of recombinant S. cerevisiae strains. In parallel, novel xylose
isomerases and reductases were isolated from soil metagenome libraries by
sequence- and activity-based screening methods. In addition a novel indirect
protocol for soil DNA extraction that enabled the isolation of environmental
DNA at high yield and purity was developed.
This study enabled the expansion of a biocatalyst toolbox by providing new
catalysts, screening methods and generating new recombinant strains with
improved properties, which can be utilized in the pharmaceutical and bioenergy
sectors, and thus constitutes a step forward in the development of novel biobased
processes. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1680135
- author
- Skorupa Parachin, Nadia LU
- supervisor
- opponent
-
- Nevoigt, Elke, Jacobs University, Bremen, Germany
- organization
- publishing date
- 2010
- type
- Thesis
- publication status
- published
- subject
- keywords
- industrial biocatalysts, metagenomics, biocatalyst, Saccharomyces cerevisiae
- pages
- 110 pages
- defense location
- Lecture hall B, Center of Chemistry and Chemical Engineering, Getingevägen 60, Lund University Faculty of Engineering
- defense date
- 2010-10-14 10:00:00
- ISBN
- 978-91-7473-011-1
- language
- English
- LU publication?
- yes
- id
- d705c268-0be0-4751-b8f5-588d8c59fcc4 (old id 1680135)
- date added to LUP
- 2016-04-04 13:31:52
- date last changed
- 2025-04-04 14:33:06
@phdthesis{d705c268-0be0-4751-b8f5-588d8c59fcc4,
abstract = {{Industrial biotechnology has been defined as the use and application of<br/><br>
biotechnology for the sustainable processing and production of chemicals,<br/><br>
materials and fuels. It makes use of biocatalysts such as microbial communities,<br/><br>
whole-cell microorganisms or purified enzymes. Although biocatalysts are<br/><br>
considered advantageous, since they operate under mild conditions regarding<br/><br>
temperature and pH and enable chemo-, regio-, and stereoselective reactions,<br/><br>
their utilization on the industrial scale can be impeded by sub-optimal<br/><br>
performance. The present study was aimed at the improvement of two biocatalytic<br/><br>
processes: whole-cell bioreduction for the production of optically pure<br/><br>
alcohols, and ethanol production from lignocellulosic feedstock.<br/><br>
The reduction of the bicyclic diketone, bicyclo[2.2.2]octane-2,6-dione into<br/><br>
1R,4S,6S-6-hydroxy-bicyclo[2.2.2]octane-2-one (endo-alcohol) and 1S,4R,6S-6-<br/><br>
hydroxy-bicyclo[2.2.2]octane-2-one (exo-alcohol) was used as a model bioreduction<br/><br>
reaction. The identification and overexpression of an exo-reductase<br/><br>
encoding gene in Candida tropicalis enabled the production of the uncommon<br/><br>
exo-alcohol as major product. In parallel, the advantages and disadvantages of<br/><br>
metabolically engineered Saccharomyces cerevisiae and Escherichia coli as host<br/><br>
for whole-cell bioreduction were compared for the production of the endoalcohol.<br/><br>
Both these microorganisms gave about the same product purity. While<br/><br>
E. coli showed a three times higher reduction rate, higher cell viability was<br/><br>
maintained during the bioreductions with recombinant S. cerevisiae, which<br/><br>
resulted in higher final conversion (95%) and indicated that yeast could be<br/><br>
recycled.<br/><br>
Improvement of bioethanol production from xylose was achieved through the<br/><br>
construction and use of a kinetic model as a simulation tool for metabolic<br/><br>
engineering of recombinant S. cerevisiae strains. In parallel, novel xylose<br/><br>
isomerases and reductases were isolated from soil metagenome libraries by<br/><br>
sequence- and activity-based screening methods. In addition a novel indirect<br/><br>
protocol for soil DNA extraction that enabled the isolation of environmental<br/><br>
DNA at high yield and purity was developed.<br/><br>
This study enabled the expansion of a biocatalyst toolbox by providing new<br/><br>
catalysts, screening methods and generating new recombinant strains with<br/><br>
improved properties, which can be utilized in the pharmaceutical and bioenergy<br/><br>
sectors, and thus constitutes a step forward in the development of novel biobased<br/><br>
processes.}},
author = {{Skorupa Parachin, Nadia}},
isbn = {{978-91-7473-011-1}},
keywords = {{industrial biocatalysts; metagenomics; biocatalyst; Saccharomyces cerevisiae}},
language = {{eng}},
school = {{Lund University}},
title = {{Biocatalyst Engineering: Metabolic Engineering, Kinetic modeling and metagenomics applied to industrial biotechnology}},
year = {{2010}},
}