Shifting the optimum pH of Bacillus circulans xylanase towards acidic side by introducing arginine

Pokhrel, Subarna; Joo, Jeong Chan; Yoo, Young Je

doi:10.1007/s12257-012-0455-x

Cited by 26 publications

(14 citation statements)

References 32 publications

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“…For example, neutrophilic XynC of Fibrobacter succinogenes (Zhu et al 1994) and Xyl-11 from A. versicolor (Carmona et al 1998) having a pH optima of 6.0 carries an Asp at the position. Xylanases differing in their optimum pH have got specific industrial importance in various fields which are already discussed in the review and because of the usefulness of the acidophilic enzymes; several attempts are being made to shift the pH optima of the xylanases in the acidic range (Pokhrel et al 2013). Afterward, another classification system was introduced that in general classifies glycosidases (E.C.3.2.1-) into different category based on their primary structure comparisons of the catalytic domain (which forms a database named CAZy) (Henrissat et al 1989;Henrissat and Coutinho 2001;Collins et al 2005).…”

Section: Types Of Endo-1 4-β-xylanasementioning

confidence: 99%

“…In most of the cases, the acidophilic xylanases are found to be produced by fungi (Enshasy et al 2016). These acid-stable xylanases have many industrial values (Tenkanen et al 1997;Pokhrel et al 2013;Chen et al 2016). It has been found that the acidic media accelerates the breakdown of xylan present in lignocellulosic biomass.…”

Section: Introductionmentioning

confidence: 99%

“…Literature suggests that the acidophilic xylanases are also desirable in biobleaching (Tenkanen et al 1997), baking, and fruit juice clarification or xylooligosaccharides production (Sharma et al 2016). Because of the so many benefits of acidophilic xylanases, research is being carried out to shift the pH optima of neutral/alkaliphilic xylanases towards acidic side (Pokhrel et al 2013). This review presents a concise idea about the industrial usefulness of acidophilic xylanases (Table 1) that are available in Protein Data Bank in addition to their structure-function relationship.…”

Section: Introductionmentioning

confidence: 99%

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Molecular structure and catalytic mechanism of fungal family G acidophilic xylanases

Dey

Roy

2018

3 Biotech

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Industrial applications of xylanases have made this enzyme an important subject of applied research work. Function of this particular enzyme is to degrade or hydrolyze the plentiful polysaccharide xylan, an important component of hemicellulose. It mainly cleaves the backbone of xylan that is made up of a number of xylose residues connected with β-1,4-glycosidic linkages. Fungi with mycelia are regarded as the best producer of xylanases. These varied xylanases not only differ in their sizes and shapes but also differ in their physicochemical properties. Depending on the optimum pH in which they work best, they have been classified into (1) acidophilic xylanases active at low pH or acidic pH range, (2) alkaliphilic xylanases that are active at high or alkaline pH range and (3) neutral xylanases having pH optima in the neutral range between pH 5 and 7. Other researchers have classified the xylanases also on the basis of their structural properties, kinetic parameters, etc. This review discusses the molecular structures of some acidophilic xylanases and the molecular basis of low pH optima observed for their activities. It also discusses their unique catalytic mechanism and actual role of the catalytic residues found in them. Apart from these, the review also discusses different applications of these acidophilic xylanases in different industries. The article concludes with brief suggestions about how these acidophilic xylanases can be created employing the techniques of genetic engineering and concepts of synthetic evolution, using the traits of the known acidophilic xylanases discussed in the review.

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Section: Types Of Endo-1 4-β-xylanasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular structure and catalytic mechanism of fungal family G acidophilic xylanases

Dey

Roy

2018

3 Biotech

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“…For future work, it would be interesting to shift the pH optima of the oxidase and peroxidase closer together. The pH optima of several enzymes were previously shifted through site‐directed mutagenesis . By optimizing these artificial fusions of redox enzymes, novel, effective, bifunctional biocatalysts can be developed.…”

Section: Figurementioning

confidence: 99%

Creating Oxidase–Peroxidase Fusion Enzymes as a Toolbox for Cascade Reactions

et al. 2017

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A set of bifunctional oxidase–peroxidases has been prepared by fusing four distinct oxidases to a peroxidase. Although such fusion enzymes have not been observed in nature, they could be expressed and purified in good yields. Characterization revealed that the artificial enzymes retained the capability to bind the two required cofactors and were catalytically active as oxidase and peroxidase. Peroxidase fusions of alditol oxidase and chitooligosaccharide oxidase could be used for the selective detection of xylitol and cellobiose with a detection limit in the low‐micromolar range. The peroxidase fusions of eugenol oxidase and 5‐hydroxymethylfurfural oxidase could be used for dioxygen‐driven, one‐pot, two‐step cascade reactions to convert vanillyl alcohol into divanillin and eugenol into lignin oligomers. The designed oxidase–peroxidase fusions represent attractive biocatalysts that allow efficient biocatalytic cascade oxidations that only require molecular oxygen as an oxidant.

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“…These are of particular interest for biotechnological applications, such as in the food and feed industry [6,7]. Owing to the development of a new bleaching process using acidophilic xylanases [8,9], the demand for novel wild-type or engineered enzymes with such properties has grown largely. According to the CAZy database, xylanases are classified as members of 16 different glycoside hydrolase families (GH; http://www.…”

Section: Introductionmentioning

confidence: 99%

A novel acid‐tolerant β‐xylanase from Scytalidium candidum 3C for the synthesis of o‐nitrophenyl xylooligosaccharides

et al. 2020

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Endo‐β‐xylanases are hemicellulases involved in the conversion of xylans in plant biomass. Here, we report a novel acidophilic β‐xylanase (ScXynA) with high transglycosylation abilities that was isolated from the filamentous fungus Scytalidium candidum 3C. ScXynA was identified as a glycoside hydrolase family 10 (GH10) dimeric protein, with a molecular weight of 38 ± 5 kDa per subunit. The enzyme catalyzed the hydrolysis of different xylans under acidic conditions and was stable in the pH range 2.6–4.5. The kinetic parameters of ScXynA were determined in hydrolysis reactions with p‐nitrophenyl‐β‐d‐cellobioside (pNP‐β‐Cel) and p‐nitrophenyl‐β‐d‐xylobioside (pNP‐β‐Xyl2), and kcat/Km was found to be 0.43 ± 0.02 (s·mM)−1 and 57 ± 3 (s·mM)−1, respectively. In the catalysis of the transglycosylation o‐nitrophenyl‐β‐d‐xylobioside (oNP‐β‐Xyl2) acted both as a donor and an acceptor, resulting in the efficient production of o‐nitrophenyl xylooligosaccharides, with a degree of polymerization of 3–10 and o‐nitrophenyl‐β‐d‐xylotetraose (oNP‐β‐Xyl4) as the major product (18.5% yield). The modeled ScXynA structure showed a favorable position for ligand entry and o‐nitrophenyl group accommodation in the relatively open −3 subsite, while the cleavage site was covered with an extended loop. These structural features provide favorable conditions for transglycosylation with oNP‐β‐Xyl2. The acidophilic properties and high transglycosylation activity make ScXynA a suitable choice for various biotechnological applications, including the synthesis of valuable xylooligosaccharides.

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Shifting the optimum pH of Bacillus circulans xylanase towards acidic side by introducing arginine

Cited by 26 publications

References 32 publications

Molecular structure and catalytic mechanism of fungal family G acidophilic xylanases

Molecular structure and catalytic mechanism of fungal family G acidophilic xylanases

Creating Oxidase–Peroxidase Fusion Enzymes as a Toolbox for Cascade Reactions

A novel acid‐tolerant β‐xylanase from Scytalidium candidum 3C for the synthesis of o‐nitrophenyl xylooligosaccharides

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