Improved Performances and Control of Beer Fermentation Using Encapsulated α-Acetolactate Decarboxylase and Modeling

Dulieu, Claire; Moll, M.; Boudrant, Joseph; Poncelet, Denis

doi:10.1021/bp000128k

Cited by 42 publications

(17 citation statements)

References 21 publications

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“…[1][2][3][4][5][6][7][8][9][10][11] As well as having significance in the brewing process, 5 ALDC has been used for the synthesis of enantiomerically-pure diols. 6 An interesting feature of this enzyme is that it also catalyses, at a lower rate, the decarboxylation of the corresponding (R)-enantiomer of 1 to give (R)-3, and also the conversion of (R)--acetohydroxybutyrate 2 to (R)-2-hydroxypentan-3-one 5 (Scheme 1).…”

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confidence: 99%

Structure and Mechanism of Acetolactate Decarboxylase

et al. 2013

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Acetolactate decarboxylase catalyzes the conversion of both enantiomers of acetolactate to the (R)-enantiomer of acetoin, via a mechanism that has been shown to involve a prior rearrangement of the non-natural (R)-enantiomer substrate to the natural (S)-enantiomer. In this paper, a series of crystal structures of ALDC complex with designed transition state mimics are reported. These structures, coupled with inhibition studies and site-directed mutagenesis provide an improved understanding of the molecular processes involved in the stereoselective decarboxylation/protonation events. A mechanism for the transformation of each enantiomer of acetolactate is proposed.Acetolactate decarboxylase [EC 4.1.1.5] (ALDC) catalyzes the decarboxylation of (S)--acetolactate 1 (the natural substrate) and (S)--acetohydroxybutyrate 2 to (R)-acetoin 3 and (R)-3-hydroxypentan-2-one 4 respectively (Scheme 1).1-11 As well as having significance in the brewing process, 5 ALDC has been used for the synthesis of enantiomerically-pure diols. 6 An interesting feature of this enzyme is that it also catalyses, at a lower rate, the decarboxylation of the corresponding (R)-enantiomer of 1 to give (R)-3, and also the conversion of (R)--acetohydroxybutyrate 2 to (R)-2-hydroxypentan-3-one 5 (Scheme 1). [7][8][9][10][11] Scheme 1. Decarboxylation reactions catalyzed by ALDC.Through a series of very careful 13 C-labelling and circular dichroism (CD) studies by Crout and coworkers [7][8][9][10][11] and Hill et al 4 (Supplementary Information), it was established that the high stereoselectivity of the reactions of (S)-1 and (S)-2 arises from decarboxylation to an intermediate enediol (or enolate) which is subsequently protonated on the face opposite that from which carbon dioxide was lost, and at the carbon atom to which it was attached, i.e. resulting in overall inversion (Scheme 1).9,10 A similar stereoselective protonation of an enolate within a chiral enzyme environment following a decarboxylation has been reported in malonate decarboxylases. 12The results observed for the (R)-enantiomers of ALDC substrates, in contrast, proceed via prior migration of the carboxylate group to the adjacent carbon atom via a conformation in which the C-O bonds are in a syn conformation. 7,8 From (R)-1, this results in the formation of a-acetolactate of (S)-configuration, i.e. the natural substrate, which subsequently undergoes decarboxylation to (R)-acetoin 3. In the case of (R)-2, this rearrangement gives the structural isomer (S)-2-hydroxy-2-methyl-3-oxopentanoate, (S)-6, which then undergoes decarboxylation to the observed (R)-2-hydroxypentan-3-one (R)-5.7 Hence ALDC appears to catalyze both the stereoselective decarboxylation/protonation and the rearrangement reaction of the non-natural substrate.Due to a lack of X-ray crystallographic information on ALDC prior to our studies, less was known about the precise mechanism by which the enzyme directs the various reaction steps described above. Although during our analyses we became aware of a PDB d...

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Structure and Mechanism of Acetolactate Decarboxylase

et al. 2013

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“…This enzyme can be produced from natural microbes such as Brevibacillus brevis (162) or from recombinant Saccharomyces cerevisiae (163). The enzyme catalytically converts acetolactate to acetoin via a two-step reaction involving direct decarboxylation of substrate to an enol derivative and its further protonation to final product (162).…”

Section: Peroxidasementioning

confidence: 99%

“…Moreover, the off-taste due to the presence of diacetyl in beer is nullified by the action of this enzyme. Studies indicate that both free and encapsulated form of this enzyme work efficiently in the process, thus aiding the use of immobilized enzymes at reduced costs (163). Novel inorganic nanoflowers or alginate microbeads immobilized with α-acetolactate decarboxylase are promising strategies with better thermal stability, reusability and catalytic efficiency (164).…”

Section: Peroxidasementioning

confidence: 99%

Applications of Microbial Enzymes in Food Industry

Sindhu

Binod

Ummalyma

et al. 2018

Food Technol. Biotechnol.

525

230

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SUMMARYThe use of enzymes or microorganisms in food preparations is an age-old process. With the advancement of technology, novel enzymes with wide range of applications and specificity have been developed and new application areas are still being explored. Microorganisms such as bacteria, yeast and fungi and their enzymes are widely used in several food preparations for improving the taste and texture and they offer huge economic benefits to industries. Microbial enzymes are the preferred source to plants or animals due to several advantages such as easy, cost-effective and consistent production. The present review discusses the recent advancement in enzyme technology for food industries. A comprehensive list of enzymes used in food processing, the microbial source of these enzymes and the wide range of their application are discussed.

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“…Produced catechols from monophenols [257] a-Acetolactate decarboxylase, encapsulated Yeast 12-Day faster conversion of a-acetolactate and diacetyl into acetoin in beer [258] b-Glycosidases Grapes, yeasts, bacteria, fungi…”

Section: Mucuna Pruriensmentioning

confidence: 99%

Biotechnology for the production of essential oils, flavours and volatile isolates. A review.

Gounaris

2010

Flavour & Fragrance J

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Various applications of biotechnological methods for the production of volatile compounds useful to the food and pharmaceutical industries are discussed. The yields obtained from intact or genetically modified plants are compared to those achieved by microbial methods. Plant yields are too low for the products to compete commercially to those synthesized chemically. Still lower yields are obtained with in vitro-cultured plant tissues. Trangenic plants with altered methylerythritol path gave 50% more essential oil in the best case. The 100-fold increases in shikimate-derived volatiles, obtained with overexpressed alcohol dehydrogenase and five-fold more C6 volatle aldehydes and 2-phenylethanol, were produced with overexpressed lipoxygenase and 2-phenylethanol dehydrogenase, respectively. However, the most spectacular yields were observed with biotransformations catalysed by microorganisms. Kluyveromyces marxianus, produces over 26 g/l 2-phenylethanol from phenyalanine, whereas Candida sorbophila, Mucor circillenoides or Yarrowia lipolytica can produce 5-40 g/l g-decalactone from ricinoleic acid. Vanillin production from ferulic acid is in the range 12-60 g/l with Amycolatopsis and Streptomyces species. Vanillin can be produced at 5 g/l by Escherichia coli and amorphadiene yields of 37 g/l have been observed with Saccharomyces cerevisiae, both with the genetically overexpressed methyl-erythritol path. Genetically engineered b-oxidation genes result in yields of 10 g/l g-decalactone byYarrowia lipolytica and up to 80 g/l dicaboxylic acids by various yeasts. These results far exceed the theoretical limit of about 1 g/l required for consideration of a procedure as a commercially interesting process, alternative to chemical sythesis.

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Improved Performances and Control of Beer Fermentation Using Encapsulated α-Acetolactate Decarboxylase and Modeling

Cited by 42 publications

References 21 publications

Structure and Mechanism of Acetolactate Decarboxylase

Structure and Mechanism of Acetolactate Decarboxylase

Applications of Microbial Enzymes in Food Industry

Biotechnology for the production of essential oils, flavours and volatile isolates. A review.

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