scholarly journals A novel bifunctional aldehyde/alcohol dehydrogenase catalyzing reduction of acetyl-CoA to ethanol at temperatures up to 95 °C

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Qiang Wang ◽  
Chong Sha ◽  
Hongcheng Wang ◽  
Kesen Ma ◽  
Juergen Wiegle ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Alcohol Dehydrogenase ◽  
Aldehyde Dehydrogenase ◽  
Half Life ◽  
Cellulosic Ethanol ◽  
Pyrococcus Furiosus ◽  
Biochemical Properties ◽  
Cellulosic Biomass ◽  
Acetyl Coenzyme A ◽  
First Time

AbstractHyperthermophilic Thermotoga spp. are excellent candidates for the biosynthesis of cellulosic ethanol producing strains because they can grow optimally at 80 °C with ability to degrade and utilize cellulosic biomass. In T. neapolitana (Tne), a putative iron-containing alcohol dehydrogenase was, for the first time, revealed to be a bifunctional aldehyde/alcohol dehydrogenase (Fe-AAdh) that catalyzed both reactions from acetyl-coenzyme A (ac-CoA) to acetaldehyde (ac-ald), and from ac-ald to ethanol, while the putative aldehyde dehydrogenase (Aldh) exhibited only CoA-independent activity that oxidizes ac-ald to acetic acid. The biochemical properties of Fe-AAdh were characterized, and bioinformatics were analyzed. Fe-AAdh exhibited the highest activities for the reductions of ac-CoA and acetaldehyde at 80–85 °C, pH 7.54, and had a 1-h half-life at about 92 °C. The Fe-AAdh gene is highly conserved in Thermotoga spp., Pyrococcus furiosus and Thermococcus kodakarensis, indicating the existence of a fermentation pathway from ac-CoA to ethanol via acetaldehyde as the intermediate in hyperthermophiles.

A novel bifunctional aldehyde/alcohol dehydrogenase mediating ethanol formation from acetyl-CoA in hyperthermophiles

2020 ◽  
Author(s):  
Qiang Wang ◽  
Chong Sha ◽  
Hongcheng Wang ◽  
Kesen Ma ◽  
Juergen Wiegel ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Alcohol Dehydrogenase ◽  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Cellulosic Ethanol ◽  
Decarboxylase Activity ◽  
Aldh Activity ◽  
Acetyl Coa ◽  
Ethanol Formation

Abstract Background: Hyperthermophilic fermentation at temperatures above 80 °C allows in situ product removal to mitigate the ethanol toxicity, and reduces microbial contamination without autoclaving/cooling of feedstock. Many species of Thermotoga grow at temperatures up to 90 °C, and have enzymes to degrade and utilize lignocelluloses, which provide advantages for achieving consolidated processes of cellulosic ethanol production. However, no CoA-dependent aldehyde dehydrogenase (CoA-Aldh) from any hyperthermophiles has been documented in literature so far. The pyruvate ferredoxin oxidoreductases from hyperthermophiles have pyruvate decarboxylase activity, which convert about 2% and 98% of pyruvate to acetaldehyde and acetyl-CoA (ac-CoA), respectively. Acetyl-CoA can be converted to acetic acid, if there is no CoA-Aldh to convert ac-CoA to acetaldehyde and further to ethanol. Therefore, the current study aimed to identify and characterize a CoA-Aldh activity that mediates ethanol fermentation in hyperthermophiles.Results: In Thermotoga neapolitana (Tne), a hyperthermophilic iron-acetaldehyde/alcohol dehydrogenase (Fe-AAdh) was, for the first time, revealed to catalyze the ac-CoA reduction to form ethanol via an acetaldehyde intermediate, while the annotated aldh gene in Tne genome only encodes a CoA-independent Aldh that oxidizes aldehyde to acetic acid. Three other Tne alcohol dehydrogenases (Adh) exhibited specific physiological roles in ethanol formation and consumption: Fe-Adh2 mainly catalyzed the reduction of acetaldehyde to produce ethanol, and Fe-Adh1 showed significant activities only under extreme conditions, while Zn-Adh showed special activity in ethanol oxidation. In the in vitro formation of ethanol from ac-CoA, a strong synergy was observed between Fe-Adh1 and Fe-AAdh. The Fe-AAdh gene is highly conserved in Thermotoga spp. and in Pyrococus sp., which is probably responsible for ethanol metabolism in hyperthermophiles.Conclusions: Hyperthermophilic Thermotoga spp. are excellent candidates for biosynthesis of cellulosic ethanol fermentation strains. The finding of a novel hyperthermophilic CoA-Aldh activity of Tne Fe-AAdh revealed the existence of a hyperthermophilic fermentation pathway from ac-CoA to ethanol, which offers a basic frame for in vitro synthesis of a highly active AAdh for effective ethanol fermentation pathway in hyperthermophiles, which is a key element for the approach to the consolidated processes of cellulosic ethanol production.

Antidotes Against Methanol Poisoning: A Review

2019 ◽  
Vol 19 (14) ◽  
pp. 1126-1133 ◽  
Author(s):  
Miroslav Pohanka
Keyword(s):  
Acetic Acid ◽  
Alcohol Dehydrogenase ◽  
Aldehyde Dehydrogenase ◽  
Competitive Inhibitor ◽  
Methanol Metabolism ◽  
Methanol Poisoning ◽  
Tetrahydrofolic Acid ◽  
Alcohol Dehydrogenase 2 ◽  
Antidotal Therapy

Methanol is the simplest alcohol. Compared to ethanol that is fully detoxified by metabolism. Methanol gets activated in toxic products by the enzymes, alcohol dehydrogenase and aldehyde dehydrogenase. Paradoxically, the same enzymes convert ethanol to harmless acetic acid. This review is focused on a discussion and overview of the literature devoted to methanol toxicology and antidotal therapy. Regarding the antidotal therapy, three main approaches are presented in the text: 1) ethanol as a competitive inhibitor in alcohol dehydrogenase; 2) use of drugs like fomepizole inhibiting alcohol dehydrogenase; 3) tetrahydrofolic acid and its analogues reacting with the formate as a final product of methanol metabolism. All the types of antidotal therapies are described and how they protect from toxic sequelae of methanol is explained.

scholarly journals Structure of a bifunctional alcohol dehydrogenase involved in bioethanol generation inGeobacillus thermoglucosidasius

2013 ◽  
Vol 69 (10) ◽  
pp. 2104-2115 ◽  
Author(s):  
Jonathan Extance ◽  
Susan J. Crennell ◽  
Kirstin Eley ◽  
Roger Cripps ◽  
David W. Hough ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Domain Structure ◽  
Aldehyde Dehydrogenase ◽  
In Silico ◽  
Homology Model ◽  
Structural Mechanism ◽  
Geobacillus Thermoglucosidasius ◽  
Fermentative Metabolism ◽  
Acyl Coenzyme A ◽  
First Time

Bifunctional alcohol/aldehyde dehydrogenase (ADHE) enzymes are found within many fermentative microorganisms. They catalyse the conversion of an acyl-coenzyme A to an alcoholviaan aldehyde intermediate; this is coupled to the oxidation of two NADH molecules to maintain the NAD+pool during fermentative metabolism. The structure of the alcohol dehydrogenase (ADH) domain of an ADHE protein from the ethanol-producing thermophileGeobacillus thermoglucosidasiushas been determined to 2.5 Å resolution. This is the first structure to be reported for such a domain.In silicomodelling has been carried out to generate a homology model of the aldehyde dehydrogenase domain, and this was subsequently docked with the ADH-domain structure to model the structure of the complete ADHE protein. This model suggests, for the first time, a structural mechanism for the formation of the large multimeric assemblies or `spirosomes' that are observed for this ADHE protein and which have previously been reported for ADHEs from other organisms.

Binding of 131I-Labeled Tissue-Type Plasminogen Activator on De-Endothelialized Lesions in Rabbits

1987 ◽  
Vol 26 (05) ◽  
pp. 224-228 ◽  
Author(s):  
Y. Isaka ◽  
H. Etani ◽  
K. Kimura ◽  
S. Yoneda ◽  
T. Kamada ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Abdominal Aorta ◽  
Half Life ◽  
Balloon Catheter ◽  
Biochemical Properties ◽  
Tissue Type ◽  
Fibrin Deposition ◽  
Tissue Type Plasminogen Activator ◽  
High Affinity ◽  
Type Plasminogen Activator

Tissue-type plasminogen activator (t-PA) which has a high affinity for fibrin in the clot, was labeled with 131I by the iodogen method, and its binding to de-endothelialized lesions in the rabbit was measured to assess the detectability of thrombi. The de-endothelialized lesion was induced in the abdominal aorta with a Fogarty 4F balloon catheter. Two hours after the de-endothelialization, 131I-labeled t-PA (125 ± 46 μCi) was injected intravenously. The initial half-life of the agent in blood (n = 12) was 2.9 ± 0.4 min. The degree of binding of 131I-labeled t-PA to the de-endothelialized lesion was evaluated at 15 min (n = 6) or at 30 min (n = 6) after injection of the agent. In spite of the retention of the biochemical properties of 131I-labeled t-PA and the presence of fibrin deposition at the de-endothelialized lesion, the binding of t-PA to the lesion was not sufficiently strong. Lesion-to-control ratios (cpm/g/cpm/g) were 1.65 ± 0.40 (at 15 min) and 1.39 ± 1.31 (at 30 min), and lesion-to-blood ratios were 1.39 ± 0.32 (at 15 min) and 1.36 ± 0.23 (at 30 min). These results suggest that radiolabeled t-PA may be inappropriate as a radiopharmaceutical for the scintigraphic detection of a pre-existing thrombotic lesion.

scholarly journals Molecular Characterization of the Gene Encoding a New AmpC β-Lactamase in a Clinical Strain of Acinetobacter Genomic Species 3

2004 ◽  
Vol 48 (4) ◽  
pp. 1374-1378 ◽  
Author(s):  
Alejandro Beceiro ◽  
Lourdes Dominguez ◽  
Anna Ribera ◽  
Jordi Vila ◽  
Francisca Molina ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Molecular Characterization ◽  
Biochemical Properties ◽  
Clinical Strain ◽  
The Novel ◽  
Gene Encoding ◽  
Genomic Species ◽  
First Time

ABSTRACT A presumptive chromosomal cephalosporinase (pI, 9.0) from a clinical strain of Acinetobacter genomic species 3 (AG3) is reported. The nucleotide sequence of this β-lactamase shows for the first time the gene encoding an AmpC enzyme in AG3. In addition, the biochemical properties of the novel AG3 AmpC β-lactamase are reported

scholarly journals Cell-Free Transcription at 95°: Thermostability of Transcriptional Components and DNA Topology Requirements of Pyrococcus Transcription

Genetics ◽  
1999 ◽  
Vol 152 (4) ◽  
pp. 1325-1333
Author(s):  
Carina Hethke ◽  
Agnes Bergerat ◽  
Winfried Hausner ◽  
Patrick Forterre ◽  
Michael Thomm
Keyword(s):  
Transcription Factors ◽  
Half Life ◽  
Pyrococcus Furiosus ◽  
Polymerase Activity ◽  
Supercoiled Dna ◽  
Eukaryotic Transcription ◽  
Transcription System ◽  
Archaeal Transcription ◽  
Protein Components

Abstract Cell-free transcription of archaeal promoters is mediated by two archaeal transcription factors, aTBP and TFB, which are orthologues of the eukaryotic transcription factors TBP and TFIIB. Using the cell-free transcription system described for the hyperthermophilic Archaeon Pyrococcus furiosus by Hethke et al., the temperature limits and template topology requirements of archaeal transcription were investigated. aTBP activity was not affected after incubation for 1 hr at 100°. In contrast, the half-life of RNA polymerase activity was 23 min and that of TFB activity was 3 min. The half-life of a 328-nt RNA product was 10 min at 100°. Best stability of RNA was observed at pH 6, at 400 mm K-glutamate in the absence of Mg2+ ions. Physiological concentrations of K-glutamate were found to stabilize protein components in addition, indicating that salt is an important extrinsic factor contributing to thermostability. Both RNA and proteins were stabilized by the osmolyte betaine at a concentration of 1 m. The highest activity for RNA synthesis at 95° was obtained in the presence of 1 m betaine and 400 mm K-glutamate. Positively supercoiled DNA, which was found to exist in Pyrococcus cells, can be transcribed in vitro both at 70° and 90°. However, negatively supercoiled DNA was the preferred template at all temperatures tested. Analyses of transcripts from plasmid topoisomers harboring the glutamate dehydrogenase promoter and of transcription reactions conducted in the presence of reverse gyrase indicate that positive supercoiling of DNA inhibits transcription from this promoter.

scholarly journals Model Based Biomass System Design of Feedstock Supply Systems for Bioenergy Production

2013 ◽  
Author(s):  
Kara G. Cafferty ◽  
David J. Muth ◽  
Jacob J. Jacobson ◽  
Kenneth M. Bryden
Keyword(s):  
Supply Chain ◽  
Corn Stover ◽  
Cellulosic Ethanol ◽  
Supply System ◽  
Cellulosic Biomass ◽  
Systems Dynamics ◽  
Climate Conditions ◽  
Unit Operations ◽  
Supply Systems

Engineering feedstock supply systems that deliver affordable, high-quality biomass remains a challenge for the emerging bioenergy industry. Cellulosic biomass is geographically distributed and has diverse physical and chemical properties. Because of this feedstock supply systems that deliver cellulosic biomass resources to biorefineries require integration of a broad set of engineered unit operations. These unit operations include harvest and collection, storage, preprocessing, and transportation processes. Design decisions for each feedstock supply system unit operation impact the engineering design and performance of the other system elements. These interdependencies are further complicated by spatial and temporal variances such as climate conditions and biomass characteristics. This paper develops an integrated model that couples a SQL-based data management engine and systems dynamics models to design and evaluate biomass feedstock supply systems. The integrated model, called the Biomass Logistics Model (BLM), includes a suite of databases that provide 1) engineering performance data for hundreds of equipment systems, 2) spatially explicit labor cost datasets, and 3) local tax and regulation data. The BLM analytic engine is built in the systems dynamics software package Powersim™. The BLM is designed to work with thermochemical and biochemical based biofuel conversion platforms and accommodates a range of cellulosic biomass types (i.e., herbaceous residues, short-rotation woody and herbaceous energy crops, woody residues, algae, etc.). The BLM simulates the flow of biomass through the entire supply chain, tracking changes in feedstock characteristics (i.e., moisture content, dry matter, ash content, and dry bulk density) as influenced by the various operations in the supply chain. By accounting for all of the equipment that comes into contact with biomass from the point of harvest to the throat of the conversion facility and the change in characteristics, the BLM evaluates economic performance of the engineered system, as well as determining energy consumption and green house gas performance of the design. This paper presents a BLM case study delivering corn stover to produce cellulosic ethanol. The case study utilizes the BLM to model the performance of several feedstock supply system designs. The case study also explores the impact of temporal variations in climate conditions to test the sensitivity of the engineering designs. Results from the case study show that under certain conditions corn stover can be delivered to the cellulosic ethanol biorefinery for $35/dry ton.

Alcohol and aldehyde dehydrogenase activity in the stomach and small intestine of rats poisoned with methanol

2001 ◽  
Vol 20 (5) ◽  
pp. 255-258
Author(s):  
L Chrostek ◽  
D Szczepura ◽  
M Szmitkowski ◽  
W Jelski ◽  
J Wierzchowski
Keyword(s):  
Small Intestine ◽  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Aldehyde Dehydrogenase ◽  
Protein Denaturation ◽  
Cell Damage ◽  
Sublethal Dose ◽  
Adh Activity ◽  
Aldehyde Dehydrogenase Activity

The activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) were measured with fluorogenic naphthaldehydes in the stomach and small intestine homogenates of rats dosed with 6 g methanol/kg bw after 6, 12, 24 h and 2, 5, 7 days. After intoxication with a sublethal dose, the ADH activity measured with these naphthaldehydes andALDH activities in the stomach and small intestine were significantly decreased. This inhibition is stronger in the stomach and probably depends on cell damage and protein denaturation. We conclude that the activity measured with 6-methoxy-2-naphthaldehyde (MONAL-62) may be due to the activity of rat ADH-1 isoenzyme, and the activity detected with 4-methoxy-1-naphthaldehyde (MONAL-41) to the activity of rat ADH-2 isoenzyme.

Sign in / Sign up

Export Citation Format

Share Document