Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin
<p>Abstract</p> <p>Background</p> <p>The xanthophyll astaxanthin is a high-value compound with applications in the nutraceutical, cosmetic, food, and animal feed industries. Besides chemical synthesis and extraction from naturally producing organisms like <it>Haem...
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| Format: | Article |
| Language: | English |
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BMC
2011-04-01
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| Series: | Microbial Cell Factories |
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| Online Access: | http://www.microbialcellfactories.com/content/10/1/29 |
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| author | Steuer Kristin Lemuth Karin Albermann Christoph |
| author_facet | Steuer Kristin Lemuth Karin Albermann Christoph |
| author_sort | Steuer Kristin |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>The xanthophyll astaxanthin is a high-value compound with applications in the nutraceutical, cosmetic, food, and animal feed industries. Besides chemical synthesis and extraction from naturally producing organisms like <it>Haematococcus pluvialis</it>, heterologous biosynthesis in non-carotenogenic microorganisms like <it>Escherichia coli</it>, is a promising alternative for sustainable production of natural astaxanthin. Recent achievements in the metabolic engineering of <it>E. coli </it>strains have led to a significant increase in the productivity of carotenoids like lycopene or β-carotene by increasing the metabolic flux towards the isoprenoid precursors. For the heterologous biosynthesis of astaxanthin in <it>E. coli</it>, however, the conversion of β-carotene to astaxanthin is obviously the most critical step towards an efficient biosynthesis of astaxanthin.</p> <p>Results</p> <p>Here we report the construction of the first plasmid-free <it>E. coli </it>strain that produces astaxanthin as the sole carotenoid compound with a yield of 1.4 mg/g cdw (<it>E. coli </it>BW-ASTA). This engineered <it>E. coli </it>strain harbors xanthophyll biosynthetic genes from <it>Pantoea ananatis </it>and <it>Nostoc punctiforme </it>as individual expression cassettes on the chromosome and is based on a β-carotene-producing strain (<it>E. coli </it>BW-CARO) recently developed in our lab. <it>E. coli </it>BW-CARO has an enhanced biosynthesis of the isoprenoid precursor isopentenyl diphosphate (IPP) and produces β-carotene in a concentration of 6.2 mg/g cdw. The expression of <it>crtEBIY </it>along with the β-carotene-ketolase gene <it>crtW148 </it>(NpF4798) and the β-carotene-hydroxylase gene (<it>crtZ</it>) under controlled expression conditions in <it>E. coli </it>BW-ASTA directed the pathway exclusively towards the desired product astaxanthin (1.4 mg/g cdw).</p> <p>Conclusions</p> <p>By using the λ-Red recombineering technique, genes encoding for the astaxanthin biosynthesis pathway were stably integrated into the chromosome of <it>E. coli</it>. The expression levels of chromosomal integrated recombinant biosynthetic genes were varied and adjusted to improve the ratios of carotenoids produced by this <it>E. coli </it>strain. The strategy presented, which combines chromosomal integration of biosynthetic genes with the possibility of adjusting expression by using different promoters, might be useful as a general approach for the construction of stable heterologous production strains synthesizing natural products. This is the case especially for heterologous pathways where excessive protein overexpression is a hindrance.</p> |
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| spelling | doaj.art-38ede226d5f24ad49002472a359412092022-12-22T02:13:15ZengBMCMicrobial Cell Factories1475-28592011-04-011012910.1186/1475-2859-10-29Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthinSteuer KristinLemuth KarinAlbermann Christoph<p>Abstract</p> <p>Background</p> <p>The xanthophyll astaxanthin is a high-value compound with applications in the nutraceutical, cosmetic, food, and animal feed industries. Besides chemical synthesis and extraction from naturally producing organisms like <it>Haematococcus pluvialis</it>, heterologous biosynthesis in non-carotenogenic microorganisms like <it>Escherichia coli</it>, is a promising alternative for sustainable production of natural astaxanthin. Recent achievements in the metabolic engineering of <it>E. coli </it>strains have led to a significant increase in the productivity of carotenoids like lycopene or β-carotene by increasing the metabolic flux towards the isoprenoid precursors. For the heterologous biosynthesis of astaxanthin in <it>E. coli</it>, however, the conversion of β-carotene to astaxanthin is obviously the most critical step towards an efficient biosynthesis of astaxanthin.</p> <p>Results</p> <p>Here we report the construction of the first plasmid-free <it>E. coli </it>strain that produces astaxanthin as the sole carotenoid compound with a yield of 1.4 mg/g cdw (<it>E. coli </it>BW-ASTA). This engineered <it>E. coli </it>strain harbors xanthophyll biosynthetic genes from <it>Pantoea ananatis </it>and <it>Nostoc punctiforme </it>as individual expression cassettes on the chromosome and is based on a β-carotene-producing strain (<it>E. coli </it>BW-CARO) recently developed in our lab. <it>E. coli </it>BW-CARO has an enhanced biosynthesis of the isoprenoid precursor isopentenyl diphosphate (IPP) and produces β-carotene in a concentration of 6.2 mg/g cdw. The expression of <it>crtEBIY </it>along with the β-carotene-ketolase gene <it>crtW148 </it>(NpF4798) and the β-carotene-hydroxylase gene (<it>crtZ</it>) under controlled expression conditions in <it>E. coli </it>BW-ASTA directed the pathway exclusively towards the desired product astaxanthin (1.4 mg/g cdw).</p> <p>Conclusions</p> <p>By using the λ-Red recombineering technique, genes encoding for the astaxanthin biosynthesis pathway were stably integrated into the chromosome of <it>E. coli</it>. The expression levels of chromosomal integrated recombinant biosynthetic genes were varied and adjusted to improve the ratios of carotenoids produced by this <it>E. coli </it>strain. The strategy presented, which combines chromosomal integration of biosynthetic genes with the possibility of adjusting expression by using different promoters, might be useful as a general approach for the construction of stable heterologous production strains synthesizing natural products. This is the case especially for heterologous pathways where excessive protein overexpression is a hindrance.</p>http://www.microbialcellfactories.com/content/10/1/29astaxanthinchromosomal integration<it>E. coli</it> |
| spellingShingle | Steuer Kristin Lemuth Karin Albermann Christoph Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin Microbial Cell Factories astaxanthin chromosomal integration <it>E. coli</it> |
| title | Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin |
| title_full | Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin |
| title_fullStr | Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin |
| title_full_unstemmed | Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin |
| title_short | Engineering of a plasmid-free <it>Escherichia coli </it>strain for improved <it>in vivo </it>biosynthesis of astaxanthin |
| title_sort | engineering of a plasmid free it escherichia coli it strain for improved it in vivo it biosynthesis of astaxanthin |
| topic | astaxanthin chromosomal integration <it>E. coli</it> |
| url | http://www.microbialcellfactories.com/content/10/1/29 |
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