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Metabolic engineering of Thermoanaerobacterium AK17 for increased ethanol production in seaweed hydrolysate

Moenaert, Antoine ; Bjornsdottir, Bryndís ; Haraldsson, Einar Baldvin ; Allahgholi, Leila LU ; Zieri, Anna ; Zangl, Isabella ; Sigurðardóttir, Sigríður ; Örlygsson, Jóhann ; Nordberg Karlsson, Eva LU orcid and Friðjónsson, Ólafur H , et al. (2023) In Biotechnology for Biofuels and Bioproducts 16(1).
Abstract

Sustainably produced renewable biomass has the potential to replace fossil-based feedstocks, for generation of biobased fuels and chemicals of industrial interest, in biorefineries. In this context, seaweeds contain a large fraction of carbohydrates that are a promising source for enzymatic and/or microbial biorefinery conversions. The thermoanaerobe Thermoanaerobacterium AK17 is a versatile fermentative bacterium producing ethanol, acetate and lactate from various sugars. In this study, strain AK17 was engineered for more efficient production of ethanol by knocking out the lactate and acetate side-product pathways. This was successfully achieved, but the strain reverted to acetate production by recruiting enzymes from the butyrate... (More)

Sustainably produced renewable biomass has the potential to replace fossil-based feedstocks, for generation of biobased fuels and chemicals of industrial interest, in biorefineries. In this context, seaweeds contain a large fraction of carbohydrates that are a promising source for enzymatic and/or microbial biorefinery conversions. The thermoanaerobe Thermoanaerobacterium AK17 is a versatile fermentative bacterium producing ethanol, acetate and lactate from various sugars. In this study, strain AK17 was engineered for more efficient production of ethanol by knocking out the lactate and acetate side-product pathways. This was successfully achieved, but the strain reverted to acetate production by recruiting enzymes from the butyrate pathway. Subsequently this pathway was knocked out and the resultant strain AK17_M6 could produce ethanol close to the maximum theoretical yield (90%), leading to a 1.5-fold increase in production compared to the wild-type strain. Strain AK17 was also shown to successfully ferment brown seaweed hydrolysate from Laminaria digitata to ethanol in a comparatively high yield of 0.45 g/g substrate, with the primary carbon sources for the fermentations being mannitol, laminarin-derived glucose and short laminari-oligosaccharides. As strain AK17 was successfully engineered and has a wide carbohydrate utilization range that includes mannitol from brown seaweed, as well as hexoses and pentoses found in both seaweeds and lignocellulose, the new strain AK17_M6 obtained in this study is an interesting candidate for production of ethanol from both second and third generations biomass.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biotechnology for Biofuels and Bioproducts
volume
16
issue
1
article number
135
pages
15 pages
publisher
BioMed Central (BMC)
external identifiers
  • scopus:85170650538
  • pmid:37697400
ISSN
2731-3654
DOI
10.1186/s13068-023-02388-y
language
English
LU publication?
yes
id
78f688b1-d20c-4915-b316-be7166afa970
date added to LUP
2023-09-16 07:50:12
date last changed
2024-04-19 01:02:14
@article{78f688b1-d20c-4915-b316-be7166afa970,
  abstract     = {{<p>Sustainably produced renewable biomass has the potential to replace fossil-based feedstocks, for generation of biobased fuels and chemicals of industrial interest, in biorefineries. In this context, seaweeds contain a large fraction of carbohydrates that are a promising source for enzymatic and/or microbial biorefinery conversions. The thermoanaerobe Thermoanaerobacterium AK17 is a versatile fermentative bacterium producing ethanol, acetate and lactate from various sugars. In this study, strain AK17 was engineered for more efficient production of ethanol by knocking out the lactate and acetate side-product pathways. This was successfully achieved, but the strain reverted to acetate production by recruiting enzymes from the butyrate pathway. Subsequently this pathway was knocked out and the resultant strain AK17_M6 could produce ethanol close to the maximum theoretical yield (90%), leading to a 1.5-fold increase in production compared to the wild-type strain. Strain AK17 was also shown to successfully ferment brown seaweed hydrolysate from Laminaria digitata to ethanol in a comparatively high yield of 0.45 g/g substrate, with the primary carbon sources for the fermentations being mannitol, laminarin-derived glucose and short laminari-oligosaccharides. As strain AK17 was successfully engineered and has a wide carbohydrate utilization range that includes mannitol from brown seaweed, as well as hexoses and pentoses found in both seaweeds and lignocellulose, the new strain AK17_M6 obtained in this study is an interesting candidate for production of ethanol from both second and third generations biomass.</p>}},
  author       = {{Moenaert, Antoine and Bjornsdottir, Bryndís and Haraldsson, Einar Baldvin and Allahgholi, Leila and Zieri, Anna and Zangl, Isabella and Sigurðardóttir, Sigríður and Örlygsson, Jóhann and Nordberg Karlsson, Eva and Friðjónsson, Ólafur H and Hreggviðsson, Guðmundur Óli}},
  issn         = {{2731-3654}},
  language     = {{eng}},
  month        = {{09}},
  number       = {{1}},
  publisher    = {{BioMed Central (BMC)}},
  series       = {{Biotechnology for Biofuels and Bioproducts}},
  title        = {{Metabolic engineering of <i>Thermoanaerobacterium</i> AK17 for increased ethanol production in seaweed hydrolysate}},
  url          = {{http://dx.doi.org/10.1186/s13068-023-02388-y}},
  doi          = {{10.1186/s13068-023-02388-y}},
  volume       = {{16}},
  year         = {{2023}},
}