scholarly journals Zymobacter palmae Pyruvate Decarboxylase is Less Effective Than That of Zymomonas mobilis for Ethanol Production in Metabolically Engineered Synechocystis sp. PCC6803

2019 ◽  
Vol 7 (11) ◽  
pp. 494 ◽  
Author(s):  
Lorraine Quinn ◽  
Patricia Armshaw ◽  
Tewfik Soulimane ◽  
Con Sheehan ◽  
Michael P. Ryan ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Production ◽  
Zymomonas Mobilis ◽  
Pyruvate Decarboxylase ◽  
Biomass Productivity ◽  
Gene Cassette ◽  
Major Effect ◽  
Zymobacter Palmae ◽  
Synechocystis Sp ◽  
Pcc 6803

To produce bioethanol from model cyanobacteria such as Synechocystis, a two gene cassette consisting of genes encoding pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) are required to transform pyruvate first to acetaldehyde and then to ethanol. However the partition of pyruvate to ethanol comes at a cost, a reduction in biomass and pyruvate availability for other metabolic processes. Hence strategies to divert flux to ethanol as a biofuel in Synechocystis are of interest. PDC from Zymobacter palmae (ZpPDC) has been reported to have a lower Km then the Zymomonas mobilis PDC (ZmPDC), which has traditionally been used in metabolic engineering constructs. The Zppdc gene was combined with the native slr1192 alcohol dehydrogenase gene (adhA) in an attempt to increase ethanol production in the photoautotrophic cyanobacterium Synechocystis sp. PCC 6803 over constructs created with the traditional Zmpdc. Native (Zppdc) and codon optimized (ZpOpdc) versions of the ZpPDC were cloned into a construct where pdc expression was controlled via the psbA2 light inducible promoter from Synechocystis sp. PCC 6803. These constructs were transformed into wildtype Synechocystis sp. PCC 6803 for expression and ethanol production. Ethanol levels were then compared with identical constructs containing the Zmpdc. While strains with the Zppdc (UL071) and ZpOpdc (UL072) constructs did produce ethanol, levels were lower compared to a control strain (UL070) expressing the pdc from Zymomonas mobilis. All constructs demonstrated lower biomass productivity illustrating that the flux from pyruvate to ethanol has a major effect on biomass and ultimately overall biofuel productivity. Thus the utilization of a PDC with a lower Km from Zymobacter palmae unusually did not result in enhanced ethanol production in Synechocystis sp. PCC 6803.

scholarly journals Zymobacter palmae pyruvate decarboxylase is less efficient than that of Zymomonas mobilis for ethanol production in metabolically engineered Synechocystis sp PCC6803

2019 ◽  
Author(s):  
Lorraine Quinn ◽  
Patricia Armshaw ◽  
Tewfik Soulimane ◽  
Con Sheehan ◽  
Michael P Ryan ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Production ◽  
Zymomonas Mobilis ◽  
Pyruvate Decarboxylase ◽  
Inducible Promoter ◽  
Control Strain ◽  
Zymobacter Palmae ◽  
Synechocystis Sp ◽  
Pcc 6803

AbstractPyruvate decarboxylase (PDC) from Zymobacter palmae (ZpPDC) has been reported to have a lower Km the Zymomonas mobilis PDC (ZmPDC). ZpPDC was combined with native slr1192 alcohol dehydrogenase (adh) in an attempt to increase ethanol production in the photoautotrophic cyanobacterium Synechocystis sp. PCC 6803 over constructs created with Zmpdc. Native (Zppdc) and codon optimised (ZpOpdc) versions of the ZpPDC were cloned into a construct where the pdc expression was controlled via the psbA2 light inducible promoter from Synechocystis PCC 6803. These constructs were transformed into wildtype Synechocystis PCC 6803. Ethanol levels were then compared with identical constructs containing the Zmpdc. While strains with the Zppdc (UL071) and ZpOpdc (UL072) constructs did produce ethanol, levels were lower compared to a control strain (UL004) expressing the pdc from Zymomonas mobilis. The utilisation of a PDC with a lower Km from Zymobacter palmae did not result in enhanced ethanol production in Synechocystis PCC 6803.

Effects of manipulation of pyruvate decarboxylase and alcohol dehydrogenase levels on the submergence tolerance of rice

2001 ◽  
Vol 28 (12) ◽  
pp. 1231 ◽  
Author(s):  
Musrur Rahman ◽  
Anil Grover ◽  
W. James Peacock ◽  
Elizabeth S. Dennis ◽  
Marc H. Ellis
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Production ◽  
Rice Variety ◽  
Pyruvate Decarboxylase ◽  
Inducible Promoter ◽  
Moderate Increase ◽  
Sense Orientation ◽  
Transgenic Lines ◽  
Hybrid Lines ◽  
Adh Activity

A transgenic approach was taken to manipulate the levels of pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) in rice, in order to investigate whether alteration of ethanol fermentation can affect anaerobic tolerance. A line transformed with an antisense Adh1 construct had only 4–8% of the ADH activity of untransformed plants. This line showed reduced ethanol production and coleoptile growth under anoxia. Mature plants had reduced survival when submerged in water and exposed to anoxia, suggesting that ADH plays an essential role in seed germination and plant survival in the absence of O2. A transgenic line transformed with a cotton Adh2 cDNA in the sense orientation relative to a constitutive promoter, showed 3–4-fold more ADH activity than either untransformed controls, or a flooding-tolerant rice variety (FR13A), both in air and under hypoxia. However, ethanol production by this line was only slightly higher than that of untransformed controls, and there was no increase in survival following anoxia treatments. Three independent transgenic lines containing the ricePdc1 cDNA driven by an anaerobically-inducible promoter (6XARE) showed an increase in PDC1 polypeptide in shoots, but not in roots or endosperm. A moderate increase in PDC activity and ethanol production was observed in shoots of these lines under anaerobic conditions, as well as decreased survival of shoots when submerged and exposed to anoxia. F1 plants containing both the PDC and ADH constructs showed levels of anoxia-tolerance similar to those of untransformed plants. These results suggest that over-production of PDC may be toxic to rice plants because of increased acetaldehyde. Consistent with this view, acetaldehyde levels were appreciably higher in plants over-producing PDC, compared with untransformed plants, or hybrid lines containing both the PDC and ADH constructs.

Fusion of Pyruvate Decarboxylase and Alcohol Dehydrogenase Increases Ethanol Production inEscherichia coli

2014 ◽  
Vol 3 (12) ◽  
pp. 976-978 ◽  
Author(s):  
Aleksandra J. Lewicka ◽  
Jan J. Lyczakowski ◽  
Gavin Blackhurst ◽  
Christiana Pashkuleva ◽  
Kyle Rothschild-Mancinelli ◽  
...  
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Production ◽  
Pyruvate Decarboxylase ◽  
Inescherichia Coli

scholarly journals METABOLIC CHANGES ASSOCIATED WITH OXYGEN STRESS IN PEAR FRUITS

HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1355F-1356
Author(s):  
George D. Nanos ◽  
Roger J. Romani ◽  
Adel A. Kader
Keyword(s):  
Alcohol Dehydrogenase ◽  
Ethanol Production ◽  
Ethylene Production ◽  
Pyruvate Decarboxylase ◽  
Insect Control ◽  
Pear Fruit ◽  
Oxygen Stress ◽  
Fruit Tissue ◽  
Subsequent Recovery ◽  
Alcohol Dehydrogenase Activity

The response of pear fruits and suspension-cultured pear fruit cells to 0% or 0.25% O2 is being examined to evaluate the feasibility of using such atmospheres for postharvest insect control. These treatments inhibited ethylene production, had no effect on acetaldehyde content, and increased ethanol production in pears kept at 20C for 10 days. The blossom end area of pear fruits was more prone to anaerobiosis, as indicated by increased alcohol dehydrogenase activity and ethanol content. Pear fruit plugs showed increased respiration and ethylene production rates when skin was present compared to plugs without skin. Methods for measuring activity of alcohol dehydrogenase, pyruvate decarboxylase, and pyruvate kinase have been modified and optimized and will be used to determine changes in pear fruit tissue during low O2 treatment and subsequent recovery in air.

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