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Journal Article

Hydroxynitrile lyases: At the interface of biology and chemistry

TL;DR: In chemical industries, hydroxynitrile lyase is used as an important industrial biocatalyst for the synthesis of chiral cyanohydrins by exploiting the reversible enzymatic reaction.
Abstract: Hydroxynitrile lyases are the versatile group of enzymes,which play a significant defensive role in plant system against microbial attack. In chemical industries, hydroxynitrile lyase is used as an important industrial biocatalyst for the synthesis of chiral cyanohydrins by exploiting the reversible enzymatic reaction. Cyanohydrins are biologically active compounds used in synthesis of β-amino alcohols, a-hydroxy ketones anda-hydroxy acids, which have importance as fine chemicals, Pharmaceuticals and agrochemicals. Protein engineering and site directed mutagenesis have been used to change the active site and alter the substrate specificity of various ydroxynitrile lyases. Many recombinant hydroxynitrile lyases have been expressed in Escherichia coli, Saccharomyces cerevisiae and Pichia pastoris.
Citations
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01 Jan 2011
TL;DR: The BioCassava Plus (BC+) program has employed modern biotechnologies intended to improve the health of Africans through the development and delivery of genetically engineered cassava with increased nutrient (zinc, iron, protein, and vitamin A) levels.
Abstract: More than 250 million Africans rely on the starchy root crop cassava (Manihot esculenta) as their staple source of calories. A typical cassava- based diet, however, provides less than 30% of the minimum daily requirement for protein and only 10%–20% of that for iron, zinc, and vitamin A. The BioCassava Plus (BC+) program has employed modern biotechnologies intended to improve the health of Africans through the development and delivery of genetically engineered cassava with increased nutrient (zinc, iron, protein, and vitamin A) levels. Additional traits addressed by BioCassava Plus include increased shelf life, reductions in toxic cyanogenic glycosides to safe levels, and resistance to viral disease.

214 citations

Journal ArticleDOI
TL;DR: By focusing on the hydroxynitrile lyase-catalysed synthesis of enantiopure cyanohydrins, this work gives an overview of strategies to improve commercially utilized enzymes and to suppress non-enzymatic reactions with particular emphasis on the necessity to combine approaches from different fields, such as enzyme engineering and reaction engineering.

71 citations

Journal ArticleDOI
TL;DR: Physiological and biochemical changes occurring 3 or 4 h after cassava root detachment were observed along with a correspondent increase in tissue cytoplasmic singlet oxygen presence using radical-specific fluorescent imaging of tissue samples, likely that these findings have significant implications to help understand and assist in dissection of the early events leading to the postharvest deterioration of cassavaroot.
Abstract: Cassava (Manihot esculenta Crantz) roots, the fourth most important food crop of the world, is the major carbohydrate source for more than 600 million people in Africa, parts of Latin America, Oceania, and Asia. Besides being a rich source of starch (∼80% of root), the root is also rich in vitamin C, some carotenoids, calcium, and potassium. Upon harvest, roots begin a process of physiological decay within 24–36 h called postharvest physiological deterioration or PPD. The early events leading to PPD are not known. Research to date concerning the study of PPD has mostly focused on the signaling events several hours after harvest. Upon examination of physiological and biochemical changes occurring 3 or 4 h after cassava root detachment, changes in the nature and type of volatile compounds emitted, secondary metabolites accumulated, and changes in the expression of key genes in reactive oxygen species (ROS) turnover were observed along with a correspondent increase in tissue cytoplasmic singlet oxygen presence using radical-specific fluorescent imaging of tissue samples. It is likely that these findings have significant implications to help us understand and assist in dissection of the early events leading to the postharvest deterioration of cassava root.

71 citations


Cites background from "Hydroxynitrile lyases: At the inter..."

  • ...…hydrolysis products of their respective cyanogenic glycosides (linamarins), and undergo further breakdown upon mechanical chewing of root tissue or fungal infestation, thus leading to HNL release of hydrogen cyanide (HCN) and a ketone depending on the initial substrate (Sharma et al. 2005) (Fig....

    [...]

  • ...The enzyme utilizes 2proponone cyanohydrin and 2-butanone cyanohydrin, which are hydrolysis products of their respective cyanogenic glycosides (linamarins), and undergo further breakdown upon mechanical chewing of root tissue or fungal infestation, thus leading to HNL release of hydrogen cyanide (HCN) and a ketone depending on the initial substrate (Sharma et al. 2005) (Fig....

    [...]

Journal ArticleDOI
TL;DR: A number of opportunities and challenges of nitrile metabolizing enzymes in bioprocess development for the production of bulk and fine chemicals are discussed.
Abstract: Nitrile metabolizing enzymes, i.e., aldoxime dehydratase, hydroxynitrile lyase, nitrilase, nitrile hydratase, and amidase, are the key catalysts in carbon nitrogen triple bond anabolism and catabolism. Over the past several years, these enzymes have drawn considerable attention as prominent biocatalysts in academia and industries because of their wide applications. Research on various aspects of these biocatalysts, i.e., sources, screening, function, purification, molecular cloning, structure, and mechanisms, has been conducted, and bioprocesses at various scales have been designed for the synthesis of myriads of useful compounds. This review is focused on the potential of nitrile metabolizing enzymes in the production of commercially important fine chemicals such as nitriles, carboxylic acids, and amides. A number of opportunities and challenges of nitrile metabolizing enzymes in bioprocess development for the production of bulk and fine chemicals are discussed.

47 citations


Cites background from "Hydroxynitrile lyases: At the inter..."

  • ...Few extensive reviews on hydroxynitrile lyase sources, reaction, and biochemical and molecular properties have already been published [13, 15, 47]....

    [...]

  • ...1) are group of enzymes, which catalyze cleavage and synthesis of cyanohydrins and play a significant role in plant microbial interactions [13, 43]....

    [...]

Journal ArticleDOI
TL;DR: The PeHNL from rinds had been isolated for the first time and the enzyme showed great ability in transcyanation of (R)-mandelonitrile with high e.e. in DBE as the co-organic solvent in a biphasic system.

44 citations

References
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Journal ArticleDOI
TL;DR: Results from field trials in Puerto Rico, the first confined field Trials in Nigeria, and ex ante impact analyses support the efficacy of using transgenic strategies for the biofortification of cassava.
Abstract: More than 250 million Africans rely on the starchy root crop cassava (Manihot esculenta) as their staple source of calories. A typical cassava-based diet, however, provides less than 30% of the minimum daily requirement for protein and only 10%–20% of that for iron, zinc, and vitamin A. The BioCassava Plus (BC+) program has employed modern biotechnologies intended to improve the health of Africans through the development and delivery of genetically engineered cassava with increased nutrient (zinc, iron, protein, and vitamin A) levels. Additional traits addressed by BioCassava Plus include increased shelf life, reductions in toxic cyanogenic glycosides to safe levels, and resistance to viral disease. The program also provides incentives for the adoption of biofortified cassava. Proof of concept was achieved for each of the target traits. Results from field trials in Puerto Rico, the first confined field trials in Nigeria to use genetically engineered organisms, and ex ante impact analyses support the effic...

247 citations

Journal ArticleDOI
TL;DR: Recently, protein engineering in combination with in silico methods gave rise to the development of a tailor-made HNL for large-scale manufacturing of a specific target cyanohydrin.
Abstract: The application of hydroxynitrile lyases (HNLs) as catalysts for the stereoselective condensation of HCN with carbonyl compounds has been reported as early as 1908. This enzymatic C–C bond coupling reaction furnishes enantiopure cyanohydrins which serve as versatile bifunctional building blocks for chemical synthesis. Screening of natural sources led to the discovery of both (R)- and (S)-selective HNLs, and several distinctly different classes of these enzymes with substantial differences concerning sequence, structure, and mechanism have been found. Especially during the last two centuries, HNLs have been developed into valuable biocatalysts, which can be produced in recombinant form by overexpression in microbial hosts, resulting in the implementation of industrial processes utilizing these enzymes. Recently, protein engineering in combination with in silico methods gave rise to the development of a tailor-made HNL for large-scale manufacturing of a specific target cyanohydrin.

120 citations

Journal ArticleDOI
TL;DR: By focusing on the hydroxynitrile lyase-catalysed synthesis of enantiopure cyanohydrins, this work gives an overview of strategies to improve commercially utilized enzymes and to suppress non-enzymatic reactions with particular emphasis on the necessity to combine approaches from different fields, such as enzyme engineering and reaction engineering.

71 citations

Journal ArticleDOI
TL;DR: Physiological and biochemical changes occurring 3 or 4 h after cassava root detachment were observed along with a correspondent increase in tissue cytoplasmic singlet oxygen presence using radical-specific fluorescent imaging of tissue samples, likely that these findings have significant implications to help understand and assist in dissection of the early events leading to the postharvest deterioration of cassavaroot.
Abstract: Cassava (Manihot esculenta Crantz) roots, the fourth most important food crop of the world, is the major carbohydrate source for more than 600 million people in Africa, parts of Latin America, Oceania, and Asia. Besides being a rich source of starch (∼80% of root), the root is also rich in vitamin C, some carotenoids, calcium, and potassium. Upon harvest, roots begin a process of physiological decay within 24–36 h called postharvest physiological deterioration or PPD. The early events leading to PPD are not known. Research to date concerning the study of PPD has mostly focused on the signaling events several hours after harvest. Upon examination of physiological and biochemical changes occurring 3 or 4 h after cassava root detachment, changes in the nature and type of volatile compounds emitted, secondary metabolites accumulated, and changes in the expression of key genes in reactive oxygen species (ROS) turnover were observed along with a correspondent increase in tissue cytoplasmic singlet oxygen presence using radical-specific fluorescent imaging of tissue samples. It is likely that these findings have significant implications to help us understand and assist in dissection of the early events leading to the postharvest deterioration of cassava root.

71 citations

Journal ArticleDOI
TL;DR: A number of opportunities and challenges of nitrile metabolizing enzymes in bioprocess development for the production of bulk and fine chemicals are discussed.
Abstract: Nitrile metabolizing enzymes, i.e., aldoxime dehydratase, hydroxynitrile lyase, nitrilase, nitrile hydratase, and amidase, are the key catalysts in carbon nitrogen triple bond anabolism and catabolism. Over the past several years, these enzymes have drawn considerable attention as prominent biocatalysts in academia and industries because of their wide applications. Research on various aspects of these biocatalysts, i.e., sources, screening, function, purification, molecular cloning, structure, and mechanisms, has been conducted, and bioprocesses at various scales have been designed for the synthesis of myriads of useful compounds. This review is focused on the potential of nitrile metabolizing enzymes in the production of commercially important fine chemicals such as nitriles, carboxylic acids, and amides. A number of opportunities and challenges of nitrile metabolizing enzymes in bioprocess development for the production of bulk and fine chemicals are discussed.

47 citations