Ethanol production from xylose with a pyruvate-formate-lyase mutant of Klebsiella planticola carrying a pyruvate-decarboxylase gene from Zymomonas mobilis

1989 ◽  
Vol 31 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Sigrun Feldmann ◽  
Georg A. Sprenger ◽  
Hermann Sahm
2019 ◽  
Author(s):  
Lorraine Quinn ◽  
Patricia Armshaw ◽  
Tewfik Soulimane ◽  
Con Sheehan ◽  
Michael P Ryan ◽  
...  

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.


2019 ◽  
Vol 7 (11) ◽  
pp. 494 ◽  
Author(s):  
Lorraine Quinn ◽  
Patricia Armshaw ◽  
Tewfik Soulimane ◽  
Con Sheehan ◽  
Michael P. Ryan ◽  
...  

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.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
P. Sobana Piriya ◽  
P. Thirumalai Vasan ◽  
V. S. Padma ◽  
U. Vidhyadevi ◽  
K. Archana ◽  
...  

The ethanol fermenting genes such as pyruvate decarboxylase (pdc) and alcohol dehydrogenase II (adh II) were cloned from Zymomonas mobilis and transformed into three different cellulolytic bacteria, namely Enterobacter cloacae JV, Proteus mirabilis JV and Erwinia chrysanthemi and their cellulosic ethanol production capability was studied. Recombinant E. cloacae JV was found to produce 4.5% and 3.5% (v/v) ethanol, respectively, when CMC and 4% NaOH pretreated bagasse were used as substrates, whereas recombinant P. mirabilis and E. chrysanthemi with the same substrates could only produce 4%, 3.5%, 1%, and 1.5 % of ethanol, respectively. The recombinant E. cloacae strain produced twofold higher percentage of ethanol than the wild type. The recombinant E. cloacae strain could be improved further by increasing its ethanol tolerance capability through media optimization and also by combining multigene cellulase expression for enhancing ethanol production from various types of lignocellulosic biomass so that it can be used for industrial level ethanol production.


2007 ◽  
Vol 1 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Kaewta Sootsuwan ◽  
Akira Irie ◽  
Masayuki Murata ◽  
Noppon Lertwattanasakul ◽  
Pornthap Thanonkeo ◽  
...  

Zymomonas mobilis is an alternative microorganism to Saccharomyces cerevisiae for ethanol production. To find a thermotolerant Z. mobilis strain, the growth and ethanol production of four isolates in Thailand were compared with those of the efficient strain ZM4 (NRRL B-14023) at different temperatures. One of the selected strains, TISTR 405, was found to grow and produce ethanol even at 39°C to an extent similar to that at 30°C, and the growth and ethanol productivity at 39°C were better than those of ZM4 at 30°C, suggesting that TISTR 405 is suitable for ethanol fermentation at high temperatures. Analysis of genes directly related to ethanol formation or degradation, adhA, adhB and pdc, encoding alcohol dehydrogenase (Adh) A, AdhB and pyruvate decarboxylase, respectively, revealed that these genes were highly conserved in both strains. Comparison of their gene expression and activity of the products in both TISTR 405 and ZM4 at different temperatures or growth phases indicated that there was not a great difference at the transcriptional level, but the total activity of AdhA and AdhB in TISTR 405 was higher than that in ZM4. Both strains showed a significant increase in AdhB activity in the stationary phase.


2021 ◽  
Vol 22 (11) ◽  
pp. 5628
Author(s):  
Valquíria Campos Alencar ◽  
Juliana de Fátima dos Santos Silva ◽  
Renata Ozelami Vilas Boas ◽  
Vinícius Manganaro Farnézio ◽  
Yara N. L. F. de Maria ◽  
...  

Autoinducer 2 (or AI-2) is one of the molecules used by bacteria to trigger the Quorum Sensing (QS) response, which activates expression of genes involved in a series of alternative mechanisms, when cells reach high population densities (including bioluminescence, motility, biofilm formation, stress resistance, and production of public goods, or pathogenicity factors, among others). Contrary to most autoinducers, AI-2 can induce QS responses in both Gram-negative and Gram-positive bacteria, and has been suggested to constitute a trans-specific system of bacterial communication, capable of affecting even bacteria that cannot produce this autoinducer. In this work, we demonstrate that the ethanologenic Gram-negative bacterium Zymomonas mobilis (a non-AI-2 producer) responds to exogenous AI-2 by modulating expression of genes involved in mechanisms typically associated with QS in other bacteria, such as motility, DNA repair, and nitrogen fixation. Interestingly, the metabolism of AI-2-induced Z. mobilis cells seems to favor ethanol production over biomass accumulation, probably as an adaptation to the high-energy demand of N2 fixation. This opens the possibility of employing AI-2 during the industrial production of second-generation ethanol, as a way to boost N2 fixation by these bacteria, which could reduce costs associated with the use of nitrogen-based fertilizers, without compromising ethanol production in industrial plants.


2000 ◽  
Vol 84-86 (1-9) ◽  
pp. 525-542 ◽  
Author(s):  
Mahesh S. Krishnan ◽  
Maria Blanco ◽  
Christopher K. Shattuck ◽  
Nhuan P. Nghiem ◽  
Brian H. Davison

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