Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514
Abstract Background The industrial production of various alcohols from organic carbon compounds may be performed at high rates and with a low risk of contamination using thermophilic microorganisms as whole-cell catalysts. Thermoanaerobacter species that thrive around 50–75 °C not only perform ferme...
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doaj-c4d61f7be1404107be1556bf4fbcc0912021-09-26T11:32:26ZengBMCBiotechnology for Biofuels1754-68342021-09-0114111710.1186/s13068-021-02038-1Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514Lisa Hitschler0Laura Sofie Nissen1Michelle Kuntz2Mirko Basen3Molecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/MainMicrobiology, Institute of Biological Sciences, University of RostockMolecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/MainMolecular Microbiology and Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University Frankfurt/MainAbstract Background The industrial production of various alcohols from organic carbon compounds may be performed at high rates and with a low risk of contamination using thermophilic microorganisms as whole-cell catalysts. Thermoanaerobacter species that thrive around 50–75 °C not only perform fermentation of sugars to alcohols, but some also utilize different organic acids as electron acceptors, reducing them to their corresponding alcohols. Results We purified AdhE as the major NADH- and AdhB as the major NADPH-dependent alcohol dehydrogenase (ADH) from the cell extract of the organic acid-reducing Thermoanaerobacter sp. strain X514. Both enzymes were present in high amounts during growth on glucose with and without isobutyrate, had broad substrate spectra including different aldehydes, with high affinities (< 1 mM) for acetaldehyde and for NADH (AdhE) or NADPH (AdhB). Both enzymes were highly thermostable at the physiological temperature of alcohol production. In addition to AdhE and AdhB, we identified two abundant AdhA-type ADHs based on their genes, which were recombinantly produced and biochemically characterized. The other five ADHs encoded in the genome were only expressed at low levels. Conclusions According to their biochemical and kinetic properties, AdhE and AdhB are most important for ethanol formation from sugar and reduction of organic acids to alcohols, while the role of the two AdhA-type enzymes is less clear. AdhE is the only abundant aldehyde dehydrogenase for the acetyl-CoA reduction to aldehydes, however, acid reduction may also proceed directly by aldehyde:ferredoxin oxidoreductase. The role of the latter in bio-alcohol formation from sugar and in organic acid reduction needs to be elucidated in future studies.https://doi.org/10.1186/s13068-021-02038-1ThermoanaerobacterThermophileEthanol fermentationOrganic acid reductionAlcohol dehydrogenaseAldehyde:ferredoxin oxidoreductase |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lisa Hitschler Laura Sofie Nissen Michelle Kuntz Mirko Basen |
spellingShingle |
Lisa Hitschler Laura Sofie Nissen Michelle Kuntz Mirko Basen Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514 Biotechnology for Biofuels Thermoanaerobacter Thermophile Ethanol fermentation Organic acid reduction Alcohol dehydrogenase Aldehyde:ferredoxin oxidoreductase |
author_facet |
Lisa Hitschler Laura Sofie Nissen Michelle Kuntz Mirko Basen |
author_sort |
Lisa Hitschler |
title |
Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514 |
title_short |
Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514 |
title_full |
Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514 |
title_fullStr |
Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514 |
title_full_unstemmed |
Alcohol dehydrogenases AdhE and AdhB with broad substrate ranges are important enzymes for organic acid reduction in Thermoanaerobacter sp. strain X514 |
title_sort |
alcohol dehydrogenases adhe and adhb with broad substrate ranges are important enzymes for organic acid reduction in thermoanaerobacter sp. strain x514 |
publisher |
BMC |
series |
Biotechnology for Biofuels |
issn |
1754-6834 |
publishDate |
2021-09-01 |
description |
Abstract Background The industrial production of various alcohols from organic carbon compounds may be performed at high rates and with a low risk of contamination using thermophilic microorganisms as whole-cell catalysts. Thermoanaerobacter species that thrive around 50–75 °C not only perform fermentation of sugars to alcohols, but some also utilize different organic acids as electron acceptors, reducing them to their corresponding alcohols. Results We purified AdhE as the major NADH- and AdhB as the major NADPH-dependent alcohol dehydrogenase (ADH) from the cell extract of the organic acid-reducing Thermoanaerobacter sp. strain X514. Both enzymes were present in high amounts during growth on glucose with and without isobutyrate, had broad substrate spectra including different aldehydes, with high affinities (< 1 mM) for acetaldehyde and for NADH (AdhE) or NADPH (AdhB). Both enzymes were highly thermostable at the physiological temperature of alcohol production. In addition to AdhE and AdhB, we identified two abundant AdhA-type ADHs based on their genes, which were recombinantly produced and biochemically characterized. The other five ADHs encoded in the genome were only expressed at low levels. Conclusions According to their biochemical and kinetic properties, AdhE and AdhB are most important for ethanol formation from sugar and reduction of organic acids to alcohols, while the role of the two AdhA-type enzymes is less clear. AdhE is the only abundant aldehyde dehydrogenase for the acetyl-CoA reduction to aldehydes, however, acid reduction may also proceed directly by aldehyde:ferredoxin oxidoreductase. The role of the latter in bio-alcohol formation from sugar and in organic acid reduction needs to be elucidated in future studies. |
topic |
Thermoanaerobacter Thermophile Ethanol fermentation Organic acid reduction Alcohol dehydrogenase Aldehyde:ferredoxin oxidoreductase |
url |
https://doi.org/10.1186/s13068-021-02038-1 |
work_keys_str_mv |
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