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Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose
BACKGROUND: The trisaccharide 2(′)-fucosyllactose (2(′)-FL) is one of the most abundant oligosaccharides found in human milk. Due to its prebiotic and anti-infective properties, 2(′)-FL is discussed as nutritional additive for infant formula. Besides chemical synthesis and extraction from human milk...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
BioMed Central
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655002/ https://www.ncbi.nlm.nih.gov/pubmed/23635327 http://dx.doi.org/10.1186/1475-2859-12-40 |
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author | Baumgärtner, Florian Seitz, Lyudmila Sprenger, Georg A Albermann, Christoph |
author_facet | Baumgärtner, Florian Seitz, Lyudmila Sprenger, Georg A Albermann, Christoph |
author_sort | Baumgärtner, Florian |
collection | PubMed |
description | BACKGROUND: The trisaccharide 2(′)-fucosyllactose (2(′)-FL) is one of the most abundant oligosaccharides found in human milk. Due to its prebiotic and anti-infective properties, 2(′)-FL is discussed as nutritional additive for infant formula. Besides chemical synthesis and extraction from human milk, 2(′)-FL can be produced enzymatically in vitro and in vivo. The most promising approach for a large-scale formation of 2(′)-FL is the whole cell biosynthesis in Escherichia coli by intracellular synthesis of GDP-L-fucose and subsequent fucosylation of lactose with an appropriate α1,2-fucosyltransferase. Even though whole cell approaches have been demonstrated for the synthesis of 2(′)-FL, further improvements of the engineered E. coli host are required to increase product yields. Furthermore, an antibiotic-free method of whole cell synthesis of 2(′)-FL is desirable to simplify product purification and to avoid traces of antibiotics in a product with nutritional purpose. RESULTS: Here we report the construction of the first selection marker-free E. coli strain that produces 2(′)-FL from lactose and glycerol. To construct this strain, recombinant genes of the de novo synthesis pathway for GDP-L-fucose as well as the gene for the H. pylori fucosyltransferase futC were integrated into the chromosome of E. coli JM109 by using the λ-Red recombineering technique. Strains carrying additional copies of the futC gene and/or the gene fkp (from Bacteroides fragilis) for an additional salvage pathway for GDP-L-fucose production were used and shown to further improve production of 2(′)-FL in shake flask experiments. An increase of the intracellular GDP-L-fucose concentration by expression of fkp gene as well as an additional copy of the futC gene lead to an enhanced formation of 2(′)-FL. Using an improved production strain, feasibility of large scale 2(′)-FL production was demonstrated in an antibiotic-free fed-batch fermentation (13 l) with a final 2(′)-FL concentration of 20.28 ± 0.83 g l(-1) and a space-time-yield of 0.57 g l(-1) h(-1). CONCLUSIONS: By chromosomal integration of recombinant genes, altering the copy number of these genes and analysis of 2(′)-FL and intracellular GDP-L-fucose levels, we were able to construct and improve the first selection marker-free E. coli strain which is capable to produce 2(′)-FL without the use of expression plasmids. Analysis of intracellular GDP-L-fucose levels identified the de novo synthesis pathway of GDP-L-fucose as one bottleneck in 2(′)-FL production. In antibiotic-free fed-batch fermentation with an improved strain, scale-up of 2(′)-FL could be demonstrated. |
format | Online Article Text |
id | pubmed-3655002 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | BioMed Central |
record_format | MEDLINE/PubMed |
spelling | pubmed-36550022013-05-20 Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose Baumgärtner, Florian Seitz, Lyudmila Sprenger, Georg A Albermann, Christoph Microb Cell Fact Research BACKGROUND: The trisaccharide 2(′)-fucosyllactose (2(′)-FL) is one of the most abundant oligosaccharides found in human milk. Due to its prebiotic and anti-infective properties, 2(′)-FL is discussed as nutritional additive for infant formula. Besides chemical synthesis and extraction from human milk, 2(′)-FL can be produced enzymatically in vitro and in vivo. The most promising approach for a large-scale formation of 2(′)-FL is the whole cell biosynthesis in Escherichia coli by intracellular synthesis of GDP-L-fucose and subsequent fucosylation of lactose with an appropriate α1,2-fucosyltransferase. Even though whole cell approaches have been demonstrated for the synthesis of 2(′)-FL, further improvements of the engineered E. coli host are required to increase product yields. Furthermore, an antibiotic-free method of whole cell synthesis of 2(′)-FL is desirable to simplify product purification and to avoid traces of antibiotics in a product with nutritional purpose. RESULTS: Here we report the construction of the first selection marker-free E. coli strain that produces 2(′)-FL from lactose and glycerol. To construct this strain, recombinant genes of the de novo synthesis pathway for GDP-L-fucose as well as the gene for the H. pylori fucosyltransferase futC were integrated into the chromosome of E. coli JM109 by using the λ-Red recombineering technique. Strains carrying additional copies of the futC gene and/or the gene fkp (from Bacteroides fragilis) for an additional salvage pathway for GDP-L-fucose production were used and shown to further improve production of 2(′)-FL in shake flask experiments. An increase of the intracellular GDP-L-fucose concentration by expression of fkp gene as well as an additional copy of the futC gene lead to an enhanced formation of 2(′)-FL. Using an improved production strain, feasibility of large scale 2(′)-FL production was demonstrated in an antibiotic-free fed-batch fermentation (13 l) with a final 2(′)-FL concentration of 20.28 ± 0.83 g l(-1) and a space-time-yield of 0.57 g l(-1) h(-1). CONCLUSIONS: By chromosomal integration of recombinant genes, altering the copy number of these genes and analysis of 2(′)-FL and intracellular GDP-L-fucose levels, we were able to construct and improve the first selection marker-free E. coli strain which is capable to produce 2(′)-FL without the use of expression plasmids. Analysis of intracellular GDP-L-fucose levels identified the de novo synthesis pathway of GDP-L-fucose as one bottleneck in 2(′)-FL production. In antibiotic-free fed-batch fermentation with an improved strain, scale-up of 2(′)-FL could be demonstrated. BioMed Central 2013-05-01 /pmc/articles/PMC3655002/ /pubmed/23635327 http://dx.doi.org/10.1186/1475-2859-12-40 Text en Copyright © 2013 Baumgärtner et al.; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Baumgärtner, Florian Seitz, Lyudmila Sprenger, Georg A Albermann, Christoph Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
title | Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
title_full | Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
title_fullStr | Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
title_full_unstemmed | Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
title_short | Construction of Escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
title_sort | construction of escherichia coli strains with chromosomally integrated expression cassettes for the synthesis of 2(′)-fucosyllactose |
topic | Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3655002/ https://www.ncbi.nlm.nih.gov/pubmed/23635327 http://dx.doi.org/10.1186/1475-2859-12-40 |
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