Archive for the ‘Biocatalysis’ Category

Chemical Cross-linking of lipase in Mesoporous silica: A new addition to the enzyme immobilization kit

themed issue on Enzyme Immobilization was recently published in Chemical Society Reviews encompassing the advances made in the field of enzyme immobilization and its importance in the Industrial arena. The credit goes to a simple discovery by Nelson and Griffin, who in 1916 rediscovered that artificial carrier-bound invertase on Al(OH)3 and charcoal was still catalytically active. They put to rest the claims that substances like charcoal caused inhibition of the enzymes (due to adsorption) and established that adsorption had no role in the decreased activity of the enzymes. This discovery laid the foundation for the immobilized enzymes to find wide applications in the chemical industry.

The carriers used for immobilization include natural and synthetic polymers like cellulose, starch,  polystyrene, sephadex and inorganic carriers like clay, kaolinite, silica gel etc. Of these, Mesoporous silica materials (MPS) have been found to be an attractive alternative due to their intrinsic properties. The immobilization of the enzymes on these carriers are generally carried out by physical adsorption or covalent binding, but face the problem of enzyme leaching. In order to overcome this problem, the Cross-linked enzyme aggregates (CLEAs) method has emerged of late and has been successful to a certain extent. In the present paper, the authors have explored the CLEAs of lipase from Candida sp. 99-125 immobilized in MPS and found them to be thermally and catalytically stable with  improved enzymatic activities.

As a measure of their improved properties, the activity and stability of the Cross-linked lipases in MPS (nicknamed CLL@MPA) were compared with the simple adsorbed lipases (ADL@MPA) and the native enzymes, and were found to be highly stable (at high temperatures as well as on shaking) with improved hydrolytic, esterification and transesterification activites. Although these lipases (from candida sp. 99-125) were less active than the commercially available Novzyme 435 (from candida antarctica), their cheaper costs make them a promising alternative for industrial applications.

This study thus paves the way for cheaper and effective enzyme immobilization options, which can be further extended to other enzymes and lead to potential advances in various enzyme-based industrial processes.

Lipase Candida sp. 99-125 CLEAs in MPS

Lipase CLEAs in mesoporous silica- a robust biocatalyst with increased stability and recyclability

Read more at:

Formation of lipase Candida sp. 99-125 CLEAs in mesoporous silica: characterization and catalytic properties
Jing Gao
,   Lianlian Shi,   Yanjun Jiang,   Liya Zhou and   Ying He
Catal. Sci. Technol.
, 2013, Accepted Manuscript
DOI:
10.1039/C3CY00412K


Shreesha Bhat, Web Writer Shreesha Bhat is a M.S.(Pharm.) in Medicinal Chemistry from National Institute  of  Pharmaceutical  Education and Research,  India. His area of interests  include  chemical  synthesis of biologically important  molecules  and developing  newer    methods for organic  synthesis using novel catalysts.

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Non-canonical amino-acids: An emerging ploy to assist lipases in tackling hostile environments

Posted on behalf of Shreesha Bhat

ncAAs to Lipase:” Here I come comrade, to help you combat hostile environment”

“A friend in need is a friend indeed”. This proverb was justified in an area of chemical research where a group of German scientists devised a new strategy for assisting lipases in hostile environments. Lipases have an important role in organic chemistry as biocatalysts, but have stability issues in organic solvents and other hostile environments making them industrially non-feasible. Among the various approaches used to improve the stability of enzymes, an alternative strategy involving the incorporation of non-canonical amino acids (ncAAs) into the enzymes was adopted by the researchers, which not only resulted in improved stability but also enhanced activity and efficiency.

The subject of study was a lipase obtained from the thermostable bacterium Thermoanaerobacter thermohydrosulfuricus (TTL), from which various ncAAs-containing congeners (mainly analogues of tryptophan, proline, tyrosine, methionine and phenylalanine) were prepared and screened against various organic solvents. They were also evaluated against a set of hostile environments such as metal cations, surfactants, protein reducing, alkylating and denaturing agents, etc. Some congeners conferred stability against pyridine (an important co-solvent for lipase catalyzed polymer synthesis) while some against tert-butanol (solvent for biodiesel production) which is very likely to have a positive influence in the industrial arena.

The present Communication not only demonstrates the potential advantages of using ncAAs in hostile environments but also highlights the challenges that lay ahead in selective biocatalytic transformations.

Find out more about the potential of non-canonical amino acids by reading :

Non-canonical amino acids as a useful synthetic biological tool for lipase-catalysed reactions in hostile environments
Carlos G. Acevedo-Rocha, Michael G. Hoesl, Sebastian Nehring, Marina Royter, Christina Wolschner, Birgit Wiltschi, Garabed Antranikian and Nediljko Budisa
Catal. Sci. Technol., 2013, DOI: 10.1039/C3CY20712A

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Industrial-scale enzyme catalysis a step closer

Many biocatalysts require expensive co-factors when they are used in the production of industrially relevant compounds, but a team of UK chemists has replaced one such co-factor – nicotinamide adenine dinucleotide phosphate (NADPH) – with a smaller, more practical molecule: methyl viologen.

The production of cyclohexanone has been successfully catalysed using this method, combining methyl viologen with a biocatalyst enzyme in an electrochemical microfluidic set-up.

The work, published in Catalysis Science & Technology, represents the first time such enzyme-catalysed chemistry has been carried out without a co-factor, and presents a practical and economic route to its use in large-scale synthesis.

Read the article…

Electro-enzymatic viologen-mediated substrate reduction using pentaerythritol tetranitrate reductase and a parallel, segmented fluid flow system
Karl Fisher, Stephan Mohr, David Mansell, Nicholas J. Goddard, Peter R. Fielden and Nigel S. Scrutton

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Biocatalysis: an article collection

Beers, wines and cheeses are enjoyed around the world today and have been for millennia. In fact the practices of brewing and cheese-making pre-date recorded history so it is difficult to accurately determine when we first started using naturally occurring enzymes and microorganisms to create valuable (and in this case, tastier!) products.

Biocatalysts are of course used in far more diverse applications than the creation of food-stuffs, including in many organic syntheses and in the generation of fine chemicals. Due to their natural design, they can offer superior selectivity for particular products and have a far lower environmental impact than many traditional catalysts. Our knowledge and understanding of biocatalysts has increased dramatically in the last few decades, which has allowed us to develop biologically modified and biomimetic catalysts for a range of applications.

To keep you up to date with the latest advances in this rapidly expanding field we have collected together these high impact articles and made them free to access until the 31st October!

Click here for the full list of free articles

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Biocatalysis themed issue

Catalysis Science & Technology has published its latest themed issue in the topic of Biocatalysis, guest edited by Professor Nick Turner from the University of Manchester.

As Professor Turner details in his Editorial, biotechnology is becoming increasingly more attractive from an industry perspective as the demand for environmentally sustainable processes rises.

   

Here’s a small taster of the articles included. Click here to browse the full issue.

Review: Different strategies to enahnce the activity of lipase catalysts
Marzia Marciello, Marco Filice and Jose M. Palomo

ReviewExploiting duality in nature: industrial examples of enzymatic oxidation and reduction reactions
K. Robins and A. Osorio-Lozada

Communication: Reductive dehalogenation of β-haloacrylic ester derivatives mediated by ene-reductases
Gábor Tasnádi, Christoph K. Winkler, Dorina Clay, Mélanie Hall and Kurt Faber

Paper: Enantiopure 3-methyl-3,4-dihydroisocoumarins and 3-methyl-1,2,3,4-tetrahydroisoquinolines via chemoenzymatic asymmetric transformations
Juan Mangas-Sánchez, Eduardo Busto, Vicente Gotor-Fernández and Vicente Gotor

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Incredible ionic liquids: an article collection

Ionic liquids are pretty self explanatory; they are ionic materials in a liquid state. In a ‘normal’ liquid, interactions are usually governed by Van de Waals or H-bonding forces. In ionic liquids it is ionic bonding interactions which dominate, meaning ionic liquids possess some interesting and unique properties.

The field of ionic liquids grew after Paul Walden’s observations of ethylammonium nitrate in 1914,1 since then the study and use of ionic liquids has grown phenomenally, with applications in analytics, biology, electrochemistry, physical chemistry, engineering, solvents and catalysis.

The academic and industrial interest in ionic liquids has thrown up some remarkable discoveries, particularly in recent years, so to keep you up to date with latest break-through research in the field we have collected these high quality articles which are free to access!*

Click here for the full list of free articles

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Co-factor promiscuity

Scientists from Australia have demonstrated that an enzyme can catalyse different chemistries from the same substrate depending on which co-factor is present. This is the first example of an enzyme showing indiscriminate behaviour for a co-factor, resulting in a different biocatalytic reaction.

Co-factors are the non-protein part of an enzyme which are essential for catalysing the reaction. By replacing the co-factor F420 with a different co-factor, FMN, the F420-dependent reductases oxidised the substrate instead of reducing it.

 

Co-factor, F420, in FDR-catalysed aflatoxin degradation

This finding opens the door to a whole area of study devoted to examining how new co-factors can enable industrially-relevant reactions.

To read more, download the article now:

Cofactor promiscuity among F420-dependent reductases enables them to catalyse both oxidation and reduction of the same substrate
Gauri V. Lapalikar,  Matthew C. Taylor,  Andrew C. Warden,  Hideki Onagi,  James E. Hennessy,  Roger J. Mulder,
Colin Scott,  Susan E. Brown,  Robyn J. Russell,  Chris J. Easton and John G. Oakeshott

Catal. Sci. Technol., 2012, Advance Article
DOI: 10.1039/C2CY20129A

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Oxidoreductases reduce bulk-bulky hydroxy-ketones to give optically active 1,2-diols

Challenging enzymatic stereoselective reduction of sterically demanding substrates.

Challenging enzymatic stereoselective reduction of sterically demanding substrates.

Dörte Rother and colleagues have identified alcohol dehydrogenases that can be used for the stereoselective reduction of some sterically demanding ketones, under mild conditions.  The team initially screened eight enzymes, with alcohol dehydrogenase from Ralstonia sp. giving the best results.  Compounds with two chiral centres have important ‘building block’ applications as synthons for catalysts, pharmaceuticals and agrochemicals and this study demonstrates the high potential of biocatalysts in this area.

To find out more, download the article now for free now…

Stereoselective synthesis of bulky 1,2-diols with alcohol dehydrogenases
Justyna Kulig,  Robert C. Simon,  Christopher A. Rose,  Syed Masood Husain,  Matthias Häckh,  Steffen Lüdeke,  Kirsten Zeitler,  Wolfgang Kroutil,  Martina Pohl and Dörte Rother
Catal. Sci. Technol., 2012
DOI: 10.1039/C2CY20120H

This article is due to be published in our upcoming themed issue focusing on biocatalysis along with the below perspective:

Exploiting duality in nature: industrial examples of enzymatic oxidation and reduction reactions
K. Robins and A. Osorio-Lozada
Catal. Sci. Technol., 2012
DOI: 10.1039/C2CY20102J

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Reviews in Catalysis

Are you new to the field of catalysis and searching for a good starting point in the literature?
Are you an experienced researcher on the hunt for a comprehensive overview on recent advances in catalysis?

Then look no further.

Over the past year we have published a number of Perspectives and Mini Reviews authored by world-leading scientists and covering all areas of catalysis.  

Scroll down to begin browsing our reviews in:

Asymmetric organocatalysis
Metal-mediated asymmetric catalysis
Fuel synthesis
Nanocatalysis
Biomimetic and biocatalysis
Zeolitic catalysis
Photocatalysis

(more…)

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Green ionic liquids for sugar fatty acid ester biosynthesis

sugar fatty acid synthesisIn this Perspective, the use of ionic liquids as alternative reaction media to traditional organic solvents for the biosynthesis of sugar fatty acids esters is explored.  Sugar fatty acids are extremely important industrially as non-ionic surfactants in a wide range of applications in food, cosmetics and pharmaceuticals.

Read more for FREE at:

Enzymatic synthesis of sugar fatty acid esters in ionic liquids
Zhen Yang and Ze-Lin Huang
Catal. Sci. Technol., 2012, Advance Article
DOI: 10.1039/C2CY20109G

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