Characterization of Thermotoga neapolitana Alcohol Dehydrogenases in the Ethanol Fermentation Pathway
In: Biology, Jg. 11 (2022-09-01), Heft 9, S. 1318
Online
academicJournal
Zugriff:
Hyperthermophilic Thermotoga spp. are candidates for cellulosic ethanol fermentation. A bifunctional iron-acetaldehyde/alcohol dehydrogenase (Fe-AAdh) has been revealed to catalyze the acetyl-CoA (Ac-CoA) reduction to form ethanol via an acetaldehyde intermediate in Thermotoga neapolitana (T. neapolitana). In this organism, there are three additional alcohol dehydrogenases, Zn-Adh, Fe-Adh1, and Fe-Adh2, encoded by genes CTN_0257, CTN_1655, and CTN_1756, respectively. This paper reports the properties and functions of these enzymes in the fermentation pathway from Ac-CoA to ethanol. It was determined that Zn-Adh only exhibited activity when oxidizing ethanol to acetaldehyde, and no detectable activity for the reaction from acetaldehyde to ethanol. Fe-Adh1 had specific activities of approximately 0.7 and 0.4 U/mg for the forward and reverse reactions between acetaldehyde and ethanol at a pHopt of 8.5 and Topt of 95 °C. Catalyzing the reduction of acetaldehyde to produce ethanol, Fe-Adh2 exhibited the highest activity of approximately 3 U/mg at a pHopt of 7.0 and Topt of 85 °C, which were close to the optimal growth conditions. These results indicate that Fe-Adh2 and Zn-Adh are the main enzymes that catalyze ethanol formation and consumption in the hyperthermophilic bacterium, respectively.
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Characterization of Thermotoga neapolitana Alcohol Dehydrogenases in the Ethanol Fermentation Pathway
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Autor/in / Beteiligte Person: | Sha, Chong ; Wang, Qiang ; Wang, Hongcheng ; Duan, Yilan ; Xu, Chongmao ; Wu, Lian ; Ma, Kesen ; Shao, Weilan ; Jiang, Yu |
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Zeitschrift: | Biology, Jg. 11 (2022-09-01), Heft 9, S. 1318 |
Veröffentlichung: | MDPI AG, 2022 |
Medientyp: | academicJournal |
ISSN: | 2079-7737 (print) |
DOI: | 10.3390/biology11091318 |
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