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Karnaouri, Anthi C.
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Publications (10 of 11) Show all publications
Karnaouri, A. C., Matsakas, L., Bühler, S., Muraleedharan, M. N., Christakopoulos, P. & Rova, U. (2019). Tailoring Celluclast (R) Cocktail's Performance towards the Production of Prebiotic Cello-Oligosaccharides from Waste Forest Biomass. Catalysts, 9(11), Article ID 897.
Open this publication in new window or tab >>Tailoring Celluclast (R) Cocktail's Performance towards the Production of Prebiotic Cello-Oligosaccharides from Waste Forest Biomass
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2019 (English)In: Catalysts, E-ISSN 2073-4344, Vol. 9, no 11, article id 897Article in journal (Refereed) Published
Abstract [en]

The main objective of this study focused on the sustainable production of cellobiose and other cellulose-derived oligosaccharides from non-edible sources, more specifically, from forest residues. For this purpose, a fine-tuning of the performance of the commercially available enzyme mixture Celluclast® was conducted towards the optimization of cellobiose production. By enzyme reaction engineering (pH, multi-stage hydrolysis with buffer exchange, addition of β-glucosidase inhibitor), a cellobiose-rich product with a high cellobiose to glucose ratio (37.4) was achieved by utilizing organosolv-pretreated birch biomass. In this way, controlled enzymatic hydrolysis combined with efficient downstream processing, including product recovery and purification through ultrafiltration and nanofiltration, can potentially support the sustainable production of food-grade oligosaccharides from forest biomass. The potential of the hydrolysis product to support the growth of two Lactobacilli probiotic strains as a sole carbon source was also demonstrated

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
non-digestible oligosaccharides, Celluclast®, cellobiose, conduritol-B-epoxide, prebiotic, lignocellulose enzyme hydrolysis
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-77851 (URN)10.3390/catal9110897 (DOI)000502278800023 ()2-s2.0-85078137358 (Scopus ID)
Note

Godkänd;2020;Nivå 0;2020-02-25 (johcin)

Available from: 2020-02-25 Created: 2020-02-25 Last updated: 2020-04-20Bibliographically approved
Karnaouri, A. C., Antonopoulou, I., Zerva, A., Dimarogona, M., Topakas, E., Rova, U. & Christakopoulos, P. (2019). Thermophilic enzyme systems for efficient conversion of lignocellulose to valuable products: Structural insights and future perspectives for esterases and oxidative catalysts. Bioresource Technology, 279, 362-372
Open this publication in new window or tab >>Thermophilic enzyme systems for efficient conversion of lignocellulose to valuable products: Structural insights and future perspectives for esterases and oxidative catalysts
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2019 (English)In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 279, p. 362-372Article in journal (Refereed) Published
Abstract [en]

Thermophilic enzyme systems are of major importance nowadays in all industrial processes due to their great performance at elevated temperatures. In the present review, an overview of the current knowledge on the properties of thermophilic and thermotolerant carbohydrate esterases and oxidative enzymes with great thermostability is provided, with respect to their potential use in biotechnological applications. A special focus is given to the lytic polysaccharide monooxygenases that are able to oxidatively cleave lignocellulose through the use of oxygen or hydrogen peroxide as co-substrate and a reducing agent as electron donor. Structural characteristics of the enzymes, including active site conformation and surface properties are discussed and correlated with their substrate specificity and thermostability properties.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Thermophilic enzymes, Thermostability, Esterases, Laccases, Peroxidases, LPMOs, Biotransformation, Lignocellulose valorization
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-73041 (URN)10.1016/j.biortech.2019.01.062 (DOI)000458999200043 ()30685134 (PubMedID)2-s2.0-85060269655 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-02-27 (johcin)

Available from: 2019-02-27 Created: 2019-02-27 Last updated: 2019-03-08Bibliographically approved
Karnaouri, A. C., Matsakas, L., Krikigianni, E., Rova, U. & Christakopoulos, P. (2019). Valorization of waste forest biomass toward the production of cello-oligosaccharides with potential prebiotic activity by utilizing customized enzyme cocktails. Biotechnology for Biofuels, 12(1), Article ID 285.
Open this publication in new window or tab >>Valorization of waste forest biomass toward the production of cello-oligosaccharides with potential prebiotic activity by utilizing customized enzyme cocktails
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2019 (English)In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 12, no 1, article id 285Article in journal (Refereed) Published
Abstract [en]

Background

Production of value-added materials from lignocellulosic biomass residues is an emerging sector that has attracted much attention as it offers numerous benefits from an environmental and economical point of view. Non-digestible oligosaccharides represent a group of carbohydrates that are resistant to gastrointestinal digestion, and therefore, they are considered as potential prebiotic candidates. Such oligosaccharides can derive from the biomass cellulose fraction through a controlled enzymatic hydrolysis that eliminates the yield of monomers.

Results

In the present study, hydrolysis of organosolv-pretreated forest residues (birch and spruce) was tested in the presence of four cellulases (EG5, CBH7, CBH6, EG7) and one accessory enzyme (LPMO). The optimal enzyme combinations were comprised of 20% EG5, 43% CBH7, 22% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of birch and 35% EG5, 45% CBH7, 10% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of spruce, leading to 22.3% and 19.1 wt% cellulose conversion into cellobiose, respectively. Enzymatic hydrolysis was applied on scale-up reactions, and the produced oligosaccharides (consisted of > 90% cellobiose) were recovered and separated from glucose through nanofiltration at optimized temperature (50 °C) and pressure (10 bar) conditions, yielding a final product with cellobiose-to-glucose ratio of 21.1 (birch) and 20.2 (spruce). Cellobiose-rich hydrolysates were tested as fermentative substrates for different lactic acid bacteria. It was shown that they can efficiently stimulate the growth of two Lactobacilli strains.

Conclusions

Controlled enzymatic hydrolysis with processive cellulases, combined with product recovery and purification, as well as enzyme recycling can potentially support the sustainable production of food-grade oligosaccharides from forest biomass.

Place, publisher, year, edition, pages
BioMed Central, 2019
Keywords
Non-digestible oligosaccharides, Cellobiose, Processive endoglucanases, Prebiotics, Enzyme hydrolysis, Nanofiltration
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-78018 (URN)10.1186/s13068-019-1628-z (DOI)000510436800002 ()31827613 (PubMedID)2-s2.0-85076587532 (Scopus ID)
Note

Validerad;2020;Nivå 2;2020-03-10 (johcin)

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-04-16Bibliographically approved
Muraleedharan, M. N., Zouraris, D., Karantonis, A., Topakas, E., Sandgren, M., Rova, U., . . . Karnaouri, A. C. (2018). Effect of lignin fractions isolated from different biomass sources on cellulose oxidation by fungal lytic polysaccharide monooxygenases. Biotechnology for Biofuels, 11(1), Article ID 296.
Open this publication in new window or tab >>Effect of lignin fractions isolated from different biomass sources on cellulose oxidation by fungal lytic polysaccharide monooxygenases
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2018 (English)In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 11, no 1, article id 296Article in journal (Refereed) Published
Abstract [en]

Background

Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that oxidatively cleave recalcitrant lignocellulose in the presence of oxygen or hydrogen peroxide as co-substrate and a reducing agent as electron donor. One of the possible systems that provide electrons to the LPMOs active site and promote the polysaccharide degradation involves the mediation of phenolic agents, such as lignin, low-molecular-weight lignin-derived compounds and other plant phenols. In the present work, the interaction of the bulk insoluble lignin fraction extracted from pretreated biomass with LPMOs and the ability to provide electrons to the active site of the enzymes is studied.

Results

The catalytic efficiency of three LPMOs, namely MtLPMO9 with C1/C4 regioselectivity, PcLPMO9D which is a C1 active LPMO and NcLPMO9C which is a C4 LPMO, was evaluated in the presence of different lignins. It was correlated with the physicochemical and structural properties of lignins, such as the molecular weight and the composition of aromatic and aliphatic hydroxyl groups. Moreover, the redox potential of lignins was determined with the use of large amplitude Fourier Transform alternating current cyclic voltammetry method and compared to the formal potential of the Cu (II) center in the active site of the LPMOs, providing more information about the lignin-LPMO interaction. The results demonstrated the existence of low-molecular weight lignin-derived compounds that are diffused in the reaction medium, which are able to reduce the enzyme active site and subsequently utilize additional electrons from the insoluble lignin fraction to promote the LPMO oxidative activity. Regarding the bulk lignin fractions, those isolated from the organosolv pretreated materials served as the best candidates in supplying electrons to the soluble compounds and, finally, to the enzymes. This difference, based on biomass pretreatment, was also demonstrated by the activity of LPMOs on natural substrates in the presence and absence of ascorbic acid as additional reducing agent.

Conclusions

Lignins can support the action of LPMOs and serve indirectly as electron donors through low-molecular-weight soluble compounds. This ability depends on their physicochemical and structural properties and is related to the biomass source and pretreatment method.

Place, publisher, year, edition, pages
London: BMC, 2018
Keywords
Lytic polysaccharide monooxygenases, Lignin structural properties, Electron donor, Cyclic voltammetry, Redox potential, Forest biomass, Pretreatment
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-71479 (URN)10.1186/s13068-018-1294-6 (DOI)000448645700001 ()30386433 (PubMedID)2-s2.0-85055687969 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-11-07 (johcin) 

Available from: 2018-11-07 Created: 2018-11-07 Last updated: 2020-04-22Bibliographically approved
Karnaouri, A. C., Topakas, E., Matsakas, L., Rova, U. & Christakopoulos, P. (2018). Fine-tuned enzymatic hydrolysis of organosolv pretreated forest materials for the efficient production of cellobiose. Frontiers in Chemistry, 6, Article ID 128.
Open this publication in new window or tab >>Fine-tuned enzymatic hydrolysis of organosolv pretreated forest materials for the efficient production of cellobiose
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2018 (English)In: Frontiers in Chemistry, E-ISSN 2296-2646, Vol. 6, article id 128Article in journal (Refereed) Published
Abstract [en]

Non-digestible oligosaccharides (NDOs) are likely prebiotic candidates that have been related to the prevention of intestinal infections and other disorders for both humans and animals. Lignocellulosic biomass is the largest carbon source in the biosphere, therefore cello-oligosacharides (COS), especially cellobiose, are potentially the most widely available choice of NDOs. Production of COS and cellobiose with enzymes offers numerous benefits over acid-catalyzed processes, as it is milder, environmentally friendly and produces fewer by-products. Cellobiohydrolases (CBHs) and a class of endoglucanases (EGs), namely processive EGs, are key enzymes for the production of COS, as they have higher preference toward glycosidic bonds near the end of cellulose chains and are able to release soluble products. In this work, we describe the heterologous expression and characterization of two CBHs from the filamentous fungus Thermothelomyces thermophila, as well as their synergism with proccessive EGs for cellobiose release from organosolv pretreated spruce and birch. The properties, inhibition kinetics and substrate specific activities for each enzyme are described in detail. The results show that a combination of EGs belonging to Glycosyl hydrolase families 5, 6 and 9, with a CBHI and CBHII in appropriate proportions, can enhance the production of COS from forest materials, underpinning the potential of these biocatalysts in the production of NDOs.

Place, publisher, year, edition, pages
Frontiers Media S.A., 2018
Keywords
cellobiohydrolases, hydrolysis, enzymatic cocktail, cellobiose, experimental design, thermostable enzymes, prebiotics
National Category
Engineering and Technology Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-68257 (URN)10.3389/fchem.2018.00128 (DOI)000430398300001 ()2-s2.0-85047449575 (Scopus ID)
Projects
"Food-grade prebiotic oligosaccharide production, merging marine and forest resources for moving up the cellulose value-chain (ForceUpValue)"
Funder
VINNOVA, 158526
Note

Validerad;2018;Nivå 2;2018-05-03 (andbra)

Available from: 2018-04-10 Created: 2018-04-10 Last updated: 2018-12-14Bibliographically approved
Matsakas, L., Karnaouri, A. C., Cwirzen, A., Rova, U. & Christakopoulos, P. (2018). Formation of Lignin Nanoparticles by Combining Organosolv Pretreatment of Birch Biomass and Homogenization Processes. Molecules, 23(7), Article ID 1822.
Open this publication in new window or tab >>Formation of Lignin Nanoparticles by Combining Organosolv Pretreatment of Birch Biomass and Homogenization Processes
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2018 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 23, no 7, article id 1822Article in journal (Refereed) Published
Abstract [en]

Valorization of lignocellulosic biomass into a biorefinery scheme requires the use of all biomass components; in this, the lignin fraction is often underutilized. Conversion of lignin to nanoparticles is an attractive solution. Here, we investigated the effect of different lignin isolation processes and a post-treatment homogenization step on particle formation. Lignin was isolated from birch chips by using two organosolv processes, traditional organosolv (OS) and hybrid organosolv-steam explosion (HOS-SE) at various ethanol contents. For post-treatment, lignin was homogenized at 500 bar using different ethanol:water ratios. Isolation of lignin with OS resulted in unshaped lignin particles, whereas after HOS-SE, lignin micro-particles were formed directly. Addition of an acidic catalyst during HOS-SE had a negative impact on the particle formation, and the optimal ethanol content was 50⁻60% v/v. Homogenization had a positive effect as it transformed initially unshaped lignin into spherical nanoparticles and reduced the size of the micro-particles isolated by HOS-SE. Ethanol content during homogenization affected the size of the particles, with the optimal results obtained at 75% v/v. We demonstrate that organosolv lignin can be used as an excellent starting material for nanoparticle preparation, with a simple method without the need for extensive chemical modification. It was also demonstrated that tuning of the operational parameters results in nanoparticles of smaller size and with better size homogeneity.

Place, publisher, year, edition, pages
MDPI, 2018
National Category
Bioprocess Technology Infrastructure Engineering
Research subject
Biochemical Process Engineering; Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-70225 (URN)10.3390/molecules23071822 (DOI)000445301800325 ()30041408 (PubMedID)2-s2.0-85052024905 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-08-06 (andbra)

Available from: 2018-08-06 Created: 2018-08-06 Last updated: 2018-10-22Bibliographically approved
Karnaouri, A. C., Muraleedharan, M. N., Dimarogona, M., Topakas, E., Rova, U., Sandgren, M. & Christakopoulos, P. (2017). Recombinant expression of thermostable processive MtEG5 endoglucanase and its synergism with MtLPMO from Myceliophthora thermophila during the hydrolysis of lignocellulosic substrates. Biotechnology for Biofuels, 10(1), Article ID 126.
Open this publication in new window or tab >>Recombinant expression of thermostable processive MtEG5 endoglucanase and its synergism with MtLPMO from Myceliophthora thermophila during the hydrolysis of lignocellulosic substrates
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2017 (English)In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 10, no 1, article id 126Article in journal (Refereed) Published
Abstract [en]

 Background

Filamentous fungi are among the most powerful cellulolytic organisms in terrestrial ecosystems. To perform the degradation of lignocellulosic substrates, these microorganisms employ both hydrolytic and oxidative mechanisms that involve the secretion and synergism of a wide variety of enzymes. Interactions between these enzymes occur on the level of saccharification, i.e., the release of neutral and oxidized products, but sometimes also reflected in the substrate liquefaction. Although the synergism regarding the yield of neutral sugars has been extensively studied, further studies should focus on the oxidized sugars, as well as the effect of enzyme combinations on the viscosity properties of the substrates.

Results

In the present study, the heterologous expression of an endoglucanase (EG) and its combined activity together with a lytic polysaccharide monooxygenase (LPMO), both from the thermophilic fungus Myceliophthora thermophila, are described. The EG gene, belonging to the glycoside hydrolase family 5, was functionally expressed in the methylotrophic yeast Pichia pastoris. The produced MtEG5A (75 kDa) featured remarkable thermal stability and showed high specific activity on microcrystalline cellulose compared to CMC, which is indicative of its processivity properties. The enzyme was capable of releasing high amounts of cellobiose from wheat straw, birch, and spruce biomass. Addition of MtLPMO9 together with MtEG5A showed enhanced enzymatic hydrolysis yields against regenerated amorphous cellulose (PASC) by improving the release not only of the neutral but also of the oxidized sugars. Assessment of activity of MtEG5A on the reduction of viscosity of PASC and pretreated wheat straw using dynamic viscosity measurements revealed that the enzyme is able to perform liquefaction of the model substrate and the natural lignocellulosic material, while when added together with MtLPMO9, no further synergistic effect was observed.

Conclusions

The endoglucanase MtEG5A from the thermophilic fungus M. thermophila exhibited excellent properties that render it a suitable candidate for use in biotechnological applications. Its strong synergism with LPMO was reflected in sugars release, but not in substrate viscosity reduction. Based on the level of oxidative sugar formation, this is the first indication of synergy between LPMO and EG reported.

Place, publisher, year, edition, pages
BioMed Central, 2017
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-63401 (URN)10.1186/s13068-017-0813-1 (DOI)000401621000002 ()28515785 (PubMedID)2-s2.0-85020628468 (Scopus ID)
Note

Validerad; 2017; Nivå 2; 2017-05-17 (andbra)

Available from: 2017-05-17 Created: 2017-05-17 Last updated: 2018-08-31Bibliographically approved
Karnaouri, A. C., Matsakas, L., Topakas, E., Rova, U. & Christakopoulos, P. (2016). Development of Thermophilic Tailor-Made Enzyme Mixtures for the Bioconversion of Agricultural and Forest Residues (ed.). Frontiers in Microbiology, 7, Article ID 177.
Open this publication in new window or tab >>Development of Thermophilic Tailor-Made Enzyme Mixtures for the Bioconversion of Agricultural and Forest Residues
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2016 (English)In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 7, article id 177Article in journal (Refereed) Published
Abstract [en]

Even though the main components of all lignocellulosic feedstocks include cellulose, hemicellulose, as well as the protective lignin matrix, there are some differences in structure, such as in hardwoods and softwoods, which may influence the degradability of the materials. Under this view, various types of biomass might require a minimal set of enzymes that has to be tailor-made. Partially defined complex mixtures that are currently commercially used are not adapted to efficiently degrade different materials, so novel enzyme mixtures have to be customized. Development of these cocktails requires better knowledge about the specific activities involved, in order to optimize hydrolysis. The role of filamentous fungus Myceliophthora thermophila and its complete enzymatic repertoire for the bioconversion of complex carbohydrates has been widely proven. In this study, four core cellulases (MtCBH7, MtCBH6, MtEG5, and MtEG7), in the presence of other four “accessory” enzymes (mannanase, lytic polyssacharide monooxygenase MtGH61, xylanase, MtFae1a) and β-glucosidase MtBGL3, were tested as a nine-component cocktail against one model substrate (phosphoric acid swollen cellulose) and four hydrothermally pretreated natural substrates (wheat straw as an agricultural waste, birch, and spruce biomass, as forest residues). Synergistic interactions among different enzymes were determined using a suitable design of experiments methodology. The results suggest that for the hydrolysis of the pure substrate (PASC), high proportions of MtEG7 are needed for efficient yields. MtCBH7 and MtEG7 are enzymes of major importance during the hydrolysis of pretreated wheat straw, while MtCBH7 plays a crucial role in case of spruce. Cellobiohydrolases MtCBH6 and MtCBH7 act in combination and are key enzymes for the hydrolysis of the hardwood (birch). Optimum combinations were predicted from suitable statistical models which were able to further increase hydrolysis yields, suggesting that tailor-made enzyme mixtures targeted toward a particular residual biomass can help maximize hydrolysis yields. The present work demonstrates the change from “one cocktail for all” to “tailor-made cocktails” that are needed for the efficient saccharification of targeted feed stocks prior to the production of biobased products through the biorefinery concept.

National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-8498 (URN)10.3389/fmicb.2016.00177 (DOI)26909078 (PubMedID)2-s2.0-84962140634 (Scopus ID)703259a7-c6ca-486d-a5c6-c121a057b9f8 (Local ID)703259a7-c6ca-486d-a5c6-c121a057b9f8 (Archive number)703259a7-c6ca-486d-a5c6-c121a057b9f8 (OAI)
Note

Validerad; 2016; Nivå 2; 20160216 (leomat)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Karnaouri, A. C., Rova, U. & Christakopoulos, P. (2016). Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes (ed.). Molecules, 21(4), Article ID 427.
Open this publication in new window or tab >>Effect of Different Pretreatment Methods on Birch Outer Bark: New Biorefinery Routes
2016 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 21, no 4, article id 427Article in journal (Refereed) Published
Abstract [en]

A comparative study among different pretreatment methods used for the fractionation of the birch outer bark components, including steam explosion, hydrothermal and organosolv treatments based on the use of ethanol/water media, is reported. The residual solid fractions have been characterized by ATR-FTIR, 13C-solid-state NMR and morphological alterations afterpretreatment were detected by scanning electron microscopy. The general chemical composition of the untreated and treated bark including determination of extractives, suberin, lignin and monosaccharides was also studied. Composition of the residual solid fraction and relative proportions of different components, as a function of the processing conditions, could be established. Organosolv treatment produces a suberin-rich solid fraction, while duringhydrothermal and steam explosion treatment cleavage of polysaccharide bonds occurs. This work will provide a deeper fundamental knowledge of the bark chemical composition, thus increasing the utilization efficiency of birch outer bark and may create possibilities to up-scale the fractionation processes.

National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-15523 (URN)10.3390/molecules21040427 (DOI)000375155000040 ()27043513 (PubMedID)2-s2.0-84966440734 (Scopus ID)f0e30c75-2107-43f4-9e85-78bf64537f4c (Local ID)f0e30c75-2107-43f4-9e85-78bf64537f4c (Archive number)f0e30c75-2107-43f4-9e85-78bf64537f4c (OAI)
Note

Validerad; 2016; Nivå 2; 20160329 (antkar)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Karnaouri, A. C., Evangelos, T. & Christakopoulos, P. (2014). Cloning, expression, and characterization of a thermostable GH7 endoglucanase from Myceliophthora thermophila capable of high-consistency enzymatic liquefaction (ed.). Applied Microbiology and Biotechnology, 98(1), 231-242
Open this publication in new window or tab >>Cloning, expression, and characterization of a thermostable GH7 endoglucanase from Myceliophthora thermophila capable of high-consistency enzymatic liquefaction
2014 (English)In: Applied Microbiology and Biotechnology, ISSN 0175-7598, E-ISSN 1432-0614, Vol. 98, no 1, p. 231-242Article in journal (Refereed) Published
Abstract [en]

An endoglucanase gene from the thermophilic fungus Myceliophthora thermophila, belonging to the glycoside hydrolase family 7, was functionally expressed in methylotrophic yeast Pichia pastoris. The putative endoglucanase from the genomic DNA was successfully cloned in P. pastoris X-33 and the recombinant enzyme was purified to its homogeneity (65 kDa) and subsequently characterized. Substrate specificity analysis revealed that the enzyme exhibits high activity on substrates containing β-1,4-glycosidic bonds such as carboxymethyl cellulose, barley β-glucan, and cello-oligosaccharides, as well as activity on xylan-containing substrates, including arabinoxylan and oat spelt xylan. MtEG7a was proved to liquefy rapidly and efficiently pretreated wheat straw, indicating its key role to the initial step of hydrolysis of high-solids lignocellulose substrates. High thermostability of the endoglucanase reflects potential commercial significance of the enzyme

National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-10200 (URN)10.1007/s00253-013-4895-9 (DOI)000329093600021 ()2-s2.0-84891882712 (Scopus ID)8f522841-e2bd-4a08-9d16-97b7c6805f91 (Local ID)8f522841-e2bd-4a08-9d16-97b7c6805f91 (Archive number)8f522841-e2bd-4a08-9d16-97b7c6805f91 (OAI)
Note

Validerad; 2014; 20130429 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
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