Introduction to Glycoside Hydrolases: Classification, Identification and Occurrence

Shrivastava, Smriti

doi:10.1007/978-981-15-4767-6_1

Cited by 12 publications

(9 citation statements)

References 186 publications

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“…The complete breakdown of lignocellulosic polymers requires the synergistic action of multiple CAZymes ( Bredon et al, 2018 ; Liew et al, 2022 ), i.e., mainly consisting of the Glycoside Hydrolases (GHs) families such as cellulase, xylanase, hemicellulase, and pectinase ( Rastogi and Shrivastava, 2020 ; Shrivastava, 2020 ). About 41% of the CAZymes database annotated genes obtained from the Ethiopian soda lakes have been shown to belong to GHs.…”

Section: Discussionmentioning

confidence: 99%

“…Among the hemicellulase enzymes, GH43 was the most abundant family in the present study. Previous studies have reported the enzyme activities of GH43 to be β-xylosidase (EC 3.2.1.37), xylanase (EC 3.2.1.8) and exo-β-1,3-galactanase (EC 3.2.1.145; ( Shrivastava, 2020 ), which are enzymes contributing to the degradation of xylan (the main component of hemicellulose) to xylose monomers ( Houfani et al, 2021 ). One major challenge in producing biofuels from lignocellulosic biomass by enzymatic hydrolysis is that hemicellulose and lignin create a protective barrier surrounding the cellulose.…”

Section: Discussionmentioning

confidence: 99%

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Discovery of novel carbohydrate degrading enzymes from soda lakes through functional metagenomics

et al. 2022

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Extremophiles provide a one-of-a-kind source of enzymes with properties that allow them to endure the rigorous industrial conversion of lignocellulose biomass into fermentable sugars. However, the fact that most of these organisms fail to grow under typical culture conditions limits the accessibility to these enzymes. In this study, we employed a functional metagenomics approach to identify carbohydrate-degrading enzymes from Ethiopian soda lakes, which are extreme environments harboring a high microbial diversity. Out of 21,000 clones screened for the five carbohydrate hydrolyzing enzymes, 408 clones were found positive. Cellulase and amylase, gave high hit ratio of 1:75 and 1:280, respectively. A total of 378 genes involved in the degradation of complex carbohydrates were identified by combining high-throughput sequencing of 22 selected clones and bioinformatics analysis using a customized workflow. Around 41% of the annotated genes belonged to the Glycoside Hydrolases (GH). Multiple GHs were identified, indicating the potential to discover novel CAZymes useful for the enzymatic degradation of lignocellulose biomass from the Ethiopian soda Lakes. More than 73% of the annotated GH genes were linked to bacterial origins, with Halomonas as the most likely source. Biochemical characterization of the three enzymes from the selected clones (amylase, cellulase, and pectinase) showed that they are active in elevated temperatures, high pH, and high salt concentrations. These properties strongly indicate that the evaluated enzymes have the potential to be used for applications in various industrial processes, particularly in biorefinery for lignocellulose biomass conversion.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Discovery of novel carbohydrate degrading enzymes from soda lakes through functional metagenomics

et al. 2022

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“…Cellulose is the most abundant polymer in lignocellulosic biomass that requires the action of all cellulases [endoglucanase, cellobiohydrolase (CBH) and β‐glucosidase] for complete disintegration into glucose. Xylanases, that break down xylan (a major constituent of hemicellulose), comprise 20% of the global enzyme market 13,14 . Apart from bioenergy production, xylanases have massive industrial applications such as in textile, paper and pulp, wine making, animal husbandry, fruit juice clarification, etc 15 .…”

Section: Introductionmentioning

confidence: 99%

Assessment of indigenous fungal biocatalysts towards valorization of delignified physico‐chemically pretreated corn cobs and sugarcane bagasse

Rastogi

Shrivastava

2022

Biofuels Bioprod Bioref

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The conversion of plant‐based lignocellulosic materials into alternative fuels entails various pretreatment strategies (chemical, physico‐chemical or enzymatic) to boost the release of sugar constituents from biomass. This investigation reports the influence of different pretreatment techniques such as acid, alkali and steam treatment followed by enzymatic hydrolysis in single and (or) consolidated system, for releasing fermentable reducing sugars from sugarcane bagasse (SB) and corn cobs (CC) (major agricultural residues). Alkaline pretreatment facilitated maximal lignin removal, 83.2 and 69.4% from CC and SB, respectively, thereby expediting enzymatic hydrolysis by in‐house xylanases produced from indigenously isolated Aspergillus tubingensis strains, AUMS60 (Xyn60) and AUMS64 (Xyn64A, B). The major operating conditions for enzymatic treatment of raw and pretreated residues were set at a substrate loading of 2% (w/v), an enzyme loading of 100–500 U g−1 substrate and incubation at 40°C, 140 rpm for 72 h. Treatment with Xyn60 and Xyn64A, B resulted in 81.4% (72 h) and 75.9% (24 h) saccharification of delignified SB and CC, respectively. Scanning electron micrographs and Fourier transform infrared spectra corroborated structural deformations induced by physico‐chemical pretreatment processes, thereby validating the maximal enzymatic hydrolysis of delignified substrates. The analysis of enzyme hydrolysis products suggested higher saccharification of hemicellulosic fraction as compared with cellulose. The observations of the present study signify that the thermotolerant in‐house enzymes show great potential in the saccharification of lignocelluloses within a short span of time and may open a new vista for biomass valorization in the bioenergy sector. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

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“…Although hundreds of GHs (e.g., cellulases, β-xylanases, β-mannanases, β-galactosidases, α-L-rhamnosidase, etc.) from both fungal and bacterial sources have been identified and biochemically characterized, the search continues for new GHs with better properties regarding enhanced activity, selectivity, and pH/thermostability, as well as for multifunctional enzymes with industrial applications [5,11].…”

Section: Introductionmentioning

confidence: 99%

Bioconversion of Lignocellulosic Materials with the Contribution of a Multifunctional GH78 Glycoside Hydrolase from Xylaria polymorpha to Release Aromatic Fragments and Carbohydrates

Liers

Ullrich

Kellner

et al. 2021

J. Microbiol. Biotechnol.

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A bifunctional glycoside hydrolase GH78 from the ascomycete Xylaria polymorpha (XpoGH78) possesses catalytic versatility towards both glycosides and esters, which may be advantageous for the efficient degradation of the plant cell-wall complex that contains both diverse sugar residues and esterified structures. The contribution of XpoGH78 to the conversion of lignocellulosic materials without any chemical pretreatment to release the water-soluble aromatic fragments, carbohydrates, and methanol was studied. The disintegrating effect of enzymatic lignocellulose treatment can be significantly improved by using different kinds of hydrolases and phenoloxidases. The considerable changes in low (3 kDa), medium (30 kDa), and high (> 200 kDa) aromatic fragments were observed after the treatment with XpoGH78 alone or with this potent cocktail. Synergistic conversion of rape straw also resulted in a release of 17.3 mg of total carbohydrates (e.g., arabinose, galactose, glucose, mannose, xylose) per gram of substrate after incubating for 72 h. Moreover, the treatment of rape straw with XpoGH78 led to a marginal methanol release of approximately 17 μg/g and improved to 270 μg/g by cooperation with the above accessory enzymes. In the case of beech wood conversion, the combined catalysis by XpoGH78 and laccase caused an effect comparable with that of fungal strain X. polymorpha in woody cultures concerning the liberation of aromatic lignocellulose fragments.

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Introduction to Glycoside Hydrolases: Classification, Identification and Occurrence

Cited by 12 publications

References 186 publications

Discovery of novel carbohydrate degrading enzymes from soda lakes through functional metagenomics

Discovery of novel carbohydrate degrading enzymes from soda lakes through functional metagenomics

Assessment of indigenous fungal biocatalysts towards valorization of delignified physico‐chemically pretreated corn cobs and sugarcane bagasse

Bioconversion of Lignocellulosic Materials with the Contribution of a Multifunctional GH78 Glycoside Hydrolase from Xylaria polymorpha to Release Aromatic Fragments and Carbohydrates

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