The Interconversion of Vicinal Diketones and Related Compounds by Brewer's Yeast Enzymes

Hardwick, Ben C.; Donley, J. R.; Bishop, G. Reid

doi:10.1080/03610470.1976.12006188

Cited by 11 publications

(5 citation statements)

References 6 publications

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“…Alcohol dehydrogenase is a good candidate enzyme for the completion of the pathway to ( R ) ‐ 1,2‐PD. Alcohol dehydrogenase from S. cerevisiae has been shown to reduce methylglyoxal to acetol (Hardwick et al, 1975) and to reduce both enantiomers of lactaldehyde (Hoffman, 1999). Methylglyoxal is a poor substrate for alcohol dehydrogenase compared to acetaldehyde, with a K m that is 3 orders of magnitude greater (Hardwick et al, 1975).…”

Section: Discussionmentioning

confidence: 99%

“…Alcohol dehydrogenase from S. cerevisiae has been shown to reduce methylglyoxal to acetol (Hardwick et al, 1975) and to reduce both enantiomers of lactaldehyde (Hoffman, 1999). Methylglyoxal is a poor substrate for alcohol dehydrogenase compared to acetaldehyde, with a K m that is 3 orders of magnitude greater (Hardwick et al, 1975). This suggests that the expression of alcohol dehydrogenase would most likely contribute to the pathway by reducing ( R ) ‐ lactaldehyde, but it might also catalyze the reduction of methylglyoxal.…”

Section: Discussionmentioning

confidence: 99%

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Enhanced Production of (R)-1,2-Propanediol by Metabolically Engineered Escherichia coli

Altaras

Cameron

2000

Biotechnol. Prog.

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1,2-Propanediol (1,2-PD) is a major commodity chemical currently derived from propylene. Previously, we have demonstrated the production of enantiomerically pure (R)-1,2-propanediol from glucose by an engineered E. coli expressing genes for NADH-linked glycerol dehydrogenase and methylglyoxal synthase. In this work, we investigate three methods to improve 1,2-PD in E. coli. First, we investigated improving the host by eliminating production of a byproduct, lactate. To do this, we constructed strains with mutations in two enzymes involved in lactate production, lactate dehydrogenase and glyoxalase I. (Surprisingly, when mutations were made in its ability to produce lactate, one strain of E. coli [MM294], produced a small amount of 1,2-PD without any added genes.) Second, we constructed a complete pathway to 1,2-PD from the glycolytic intermediate, dihydroxyacetone phosphate. Our previous 1, 2-PD producing strains relied on at least one endogenous E. coli activity and only produced 0.7 g/L of 1,2-PD. The complete pathway involved the coexpression of methylglyoxal synthase (mgs), glycerol dehydrogenase (gldA), and either yeast alcohol dehydrogenase (adhI) or E. coli 1,2-propanediol oxidoreductase (fucO). Third, we investigated bioprocessing improvements by carrying out a fed-batch fermentation with the best engineered strain (expressing mgs, gldA, and fucO). A final titer of 4.5 g/L of (R)-1,2-PD was produced, with a final yield of 0.19 g of 1,2-PD per gram of glucose consumed. This work provides a basis for further strain and process improvement.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Enhanced Production of (R)-1,2-Propanediol by Metabolically Engineered Escherichia coli

Altaras

Cameron

2000

Biotechnol. Prog.

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“…Whilst it is known that this involves enzyme action, remarkably there is still a somewhat sketchy appreciation of which enzymes in yeast are responsible for reducing diacetyl and pentanedione. It was shown by Hardwick et al 7 that alcohol dehydrogenase (ADH 1; EC 1.1.1.1) will reduce diacetyl and pentanedione, albeit rather less efficiently than it deals with acetaldehyde, but it was also shown that yeast contains other enzymes capable of reducing the VDKs. Others have reported specific diacetyl reductases (EC 1.1.1.5) in yeast 8,14,16 .…”

Section: Introductionmentioning

confidence: 99%

Enzymology of Vicinal Diketone Reduction in Brewer's Yeast

Bamforth

Kanauchi

2004

Journal of the Institute of Brewing

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J. Inst. Brew. 110(2), 83-93, 2004Ale and lager strains of yeast contain multiple enzymes capable of reducing diacetyl and pentanedione. Alcohol dehydrogenase is probably the main activity responsible in both types of organism. Although it appears that the lager strain studied possesses a more complex portfolio of diacetyl reductases than does the ale strain, it is likely that alcohol dehydrogenase has proportionately greater impact on vicinal diketone reduction in the lager strain. Two diacetyl reductases additional to alcohol dehydrogenase were located in a partial purification operation based on lager yeast, but only a single such enzyme was revealed in ale yeast.

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“…The most significant VDKs for the beer production process are diacetyl (2,3-butanedione) and 2,3-pentanedione, due to their low flavour thresholds of 0.1 and 0.9 ppm, respectively, giving beer butter/butterscotch and toffee-like flavours [21,22]. Diacetyl, which has a significant effect on flavour, aroma and drinkability, is re-assimilated and reduced via acetoin in 2,3-butanediol, which has a flavour threshold of around 4500 ppm [22][23][24][25]. Based on the GC-MS results (Table 4), 2,3-butanediol could be detected only in the aged microfiltered (AM) samples.…”

Section: Discussionmentioning

confidence: 99%

Multivariate Analysis of the Influence of Microfiltration and Pasteurisation on the Quality of Beer during Its Shelf Life

de Lima,

Brandao,

Botelho

et al. 2023

Foods

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Gas chromatography–mass spectrometry (GC–MS), physicochemical and microbiological analyses, sensory descriptive evaluation, and multivariate analyses were applied to evaluate the efficiencies of microfiltration and pasteurization processes during the shelf life of beer. Samples of microfiltered and pasteurised beer were divided into fresh and aged groups. A forced ageing process, which consisted of storing fresh samples at 55° C for 6 days in an incubator and then keeping them under ambient conditions prior to analysis, was applied. Physicochemical analysis showed that both microfiltered and pasteurised samples had a slight variation in apparent extract, pH, and bitterness. The samples that underwent heat treatment had lower colour values compared with those that were microfiltered. Chromatographic peak areas of vicinal diketones increased in both fresh and aged samples. The results of the microbiological analysis revealed spoilage lactic acid bacteria (Lactobacillus) and yeasts (Saccharomyces and non-Saccharomyces) in fresh microfiltered samples. In the GC–MS analysis, furfural, considered by many authors as a heat indicator, was detected only in samples that underwent forced ageing and not in samples that were subjected to thermal pasteurisation. Finally, sensory analysis found differences in the organoleptic properties of fresh microfiltered samples compared with the rest of the samples.

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The Interconversion of Vicinal Diketones and Related Compounds by Brewer's Yeast Enzymes

Cited by 11 publications

References 6 publications

Enhanced Production of (R)-1,2-Propanediol by Metabolically Engineered Escherichia coli

Enhanced Production of (R)-1,2-Propanediol by Metabolically Engineered Escherichia coli

Enzymology of Vicinal Diketone Reduction in Brewer's Yeast

Multivariate Analysis of the Influence of Microfiltration and Pasteurisation on the Quality of Beer during Its Shelf Life

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