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Chirumamilla, Rajendra Rani; Muralidhar, R. V.; Marchant, Roger; Nigam, Poonam Singh Nee

doi:10.1023/a:1011904405002

Cited by 57 publications

(13 citation statements)

References 57 publications

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“…Directed evolution mimics natural evolution by combining reiterative random mutagenesis and recombination with screening or selection for enzyme variants with improved properties [109,110,111]. Compared to classical mutagenesis, directed evolution targets a specific gene of choice with random changes being performed delimited to the gene of choice, followed by evaluation of the mutants [112].…”

Section: New and Improved Beta-glucosidasesmentioning

confidence: 99%

Fungal Beta-Glucosidases: A Bottleneck in Industrial Use of Lignocellulosic Materials

et al. 2013

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Profitable biomass conversion processes are highly dependent on the use of efficient enzymes for lignocellulose degradation. Among the cellulose degrading enzymes, beta-glucosidases are essential for efficient hydrolysis of cellulosic biomass as they relieve the inhibition of the cellobiohydrolases and endoglucanases by reducing cellobiose accumulation. In this review, we discuss the important role beta-glucosidases play in complex biomass hydrolysis and how they create a bottleneck in industrial use of lignocellulosic materials. An efficient beta-glucosidase facilitates hydrolysis at specified process conditions, and key points to consider in this respect are hydrolysis rate, inhibitors, and stability. Product inhibition impairing yields, thermal inactivation of enzymes, and the high cost of enzyme production are the main obstacles to commercial cellulose hydrolysis. Therefore, this sets the stage in the search for better alternatives to the currently available enzyme preparations either by improving known or screening for new beta-glucosidases.

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Section: New and Improved Beta-glucosidasesmentioning

confidence: 99%

Fungal Beta-Glucosidases: A Bottleneck in Industrial Use of Lignocellulosic Materials

et al. 2013

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“…A large number of new enzymes have been designed with the input of protein-engineering, biochemical-reaction engineering and metagenomics. Various molecular techniques have also been applied to improve the quality and performance of microbial enzymes for their wider applications in many industries [2]. As a result, many added-value products are being synthesized in global market with the use of established bioprocess-technology employing purposely engineered biocatalyst-enzymes.…”

Section: Enzymes From Microbial Sourcesmentioning

confidence: 99%

Microbial Enzymes with Special Characteristics for Biotechnological Applications

2013

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This article overviews the enzymes produced by microorganisms, which have been extensively studied worldwide for their isolation, purification and characterization of their specific properties. Researchers have isolated specific microorganisms from extreme sources under extreme culture conditions, with the objective that such isolated microbes would possess the capability to bio-synthesize special enzymes. Various Bio-industries require enzymes possessing special characteristics for their applications in processing of substrates and raw materials. The microbial enzymes act as bio-catalysts to perform reactions in bio-processes in an economical and environmentally-friendly way as opposed to the use of chemical catalysts. The special characteristics of enzymes are exploited for their commercial interest and industrial applications, which include: thermotolerance, thermophilic nature, tolerance to a varied range of pH, stability of enzyme activity over a range of temperature and pH, and other harsh reaction conditions. Such enzymes have proven their utility in bio-industries such as food, leather, textiles, animal feed, and in bio-conversions and bio-remediations.

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“…[1,3] The usefulness of biocatalysts, such as whole cell preparations and purified enzymes, is due to the often unmatched high efficiency, chemo-, regio-and stereoselectivity of enzyme catalysed reactions. [2,4] However, naturally occurring biocatalysts can lack some properties necessary in large scale chemical synthesis, such as high activity and selectivity for non-natural substrates. [5] The OYE family of enzymes (OYE; E.C.…”

Section: Introductionmentioning

confidence: 99%

“…[17] Standard reactions for the mutants (1.0 mL) were performed in buffer (50 mm KH 2 PO 4 /K 2 HPO 4 , pH 7.0) containing alkene (5 mm; added as a DMF solution with 2 %, v/v, final concentration), NADH (6-15 mm) and PETN reductase (2 mm). The reactions were shaken at 37 8C at 130 rpm for 1.5-48 h followed by reaction termination by extraction with ethyl acetate (0.9 mL) containing an internal standard, and dried by using MgSO 4 . The extracts were analyzed by GC or HPLC to determine the % yield (amount of alkane/oxime/aldehyde product formed), % conversion (substrate consumption), and enantiomeric excess as described previously.…”

mentioning

confidence: 99%

A Site‐Saturated Mutagenesis Study of Pentaerythritol Tetranitrate Reductase Reveals that Residues 181 and 184 Influence Ligand Binding, Stereochemistry and Reactivity

et al. 2011

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We have conducted a site-specific saturation mutagenesis study of H181 and H184 of flavoprotein pentaerythritol tetranitrate reductase (PETN reductase) to probe the role of these residues in substrate binding and catalysis with a variety of α,β-unsaturated alkenes. Single mutations at these residues were sufficient to dramatically increase the enantiopurity of products formed by reduction of 2-phenyl-1-nitropropene. In addition, many mutants exhibited a switch in reactivity to predominantly catalyse nitro reduction, as opposed to CC reduction. These mutants showed an enhancement in a minor side reaction and formed 2-phenylpropanal oxime from 2-phenyl-1-nitropropene. The multiple binding conformations of hydroxy substituted nitro-olefins in PETN reductase were examined by using both structural and catalytic techniques. These compounds were found to bind in both active and inhibitory complexes; this highlights the plasticity of the active site and the ability of the H181/H184 couple to coordinate with multiple functional groups. These properties demonstrate the potential to use PETN reductase as a scaffold in the development of industrially useful biocatalysts.

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Cited by 57 publications

References 57 publications

Fungal Beta-Glucosidases: A Bottleneck in Industrial Use of Lignocellulosic Materials

Fungal Beta-Glucosidases: A Bottleneck in Industrial Use of Lignocellulosic Materials

Microbial Enzymes with Special Characteristics for Biotechnological Applications

A Site‐Saturated Mutagenesis Study of Pentaerythritol Tetranitrate Reductase Reveals that Residues 181 and 184 Influence Ligand Binding, Stereochemistry and Reactivity

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