Change search
Link to record
Permanent link

Direct link
BETA
Publications (7 of 7) Show all publications
Papaspyridi, L. M., Zerva, A. & Topakas, E. (2018). Biocatalytic synthesis of fungal β-glucans. Catalysts, 8(7), Article ID 274.
Open this publication in new window or tab >>Biocatalytic synthesis of fungal β-glucans
2018 (English)In: Catalysts, ISSN 2073-4344, Vol. 8, no 7, article id 274Article in journal (Refereed) Published
Abstract [en]

Glucans are the dominant polysaccharide constituents of fungal cell walls. Remarkably, these major bioactive polysaccharides account for the beneficial effects that have been observed by many mushrooms of medicinal interest. Accordingly, the prevailing tendency is the use of bioactive mushroom β-glucans mainly in pharmaceutical industries or as food additives, since it seems that they can be involved in meeting the overall growing demand for food in the future, but also in medical and material sectors. β-(1,3)-Glucan synthase (GLS) is the responsible enzyme for the synthesis of these important polysaccharides, which is a member of the glycosyl transferase (GT) family. For optimizing the production of such natural polymers of great interest, the comprehension of the fungal synthetic mechanism, as well as the biochemical and molecular characteristics of the key enzyme GLS and its expression seem to be crucial. Overall, in this review article, the fungal β-glucans biosynthesis by GLS is summarized, while the in vitro synthesis of major polysaccharides is also discussed, catalyzed by glycoside hydrolases (GHs) and GTs. Possible future prospects of GLS in medicine and in developing other potential artificial composite materials with industrial applications are also summarized

Place, publisher, year, edition, pages
MDPI, 2018
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-70268 (URN)10.3390/catal8070274 (DOI)000440016400021 ()2-s2.0-85050008185 (Scopus ID)
Note

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

Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-11-26Bibliographically approved
Zerva, A., Antonopoulou, I., Enman, J., Iancu, L., Rova, U. & Christakopoulos, P. (2018). Cross-Linked Enzyme Aggregates of Feruloyl Esterase Preparations from Thermothelomyces thermophila and Talaromyces wortmannii. Catalysts, 8(5), Article ID 208.
Open this publication in new window or tab >>Cross-Linked Enzyme Aggregates of Feruloyl Esterase Preparations from Thermothelomyces thermophila and Talaromyces wortmannii
Show others...
2018 (English)In: Catalysts, ISSN 2073-4344, Vol. 8, no 5, article id 208Article in journal (Refereed) Published
Abstract [en]

Cross-linked enzyme aggregates (CLEA®) technology is a well-established method in the current literature for the low-cost and effective immobilization of several enzymes. The main advantage of this particular method is the simplicity of the process, since it consists of only two steps. However, CLEA immobilization must be carefully designed for each desired enzyme, since the optimum conditions for enzymes can vary significantly, according to their physicochemical properties. In the present study, an investigation of the optimum CLEA immobilization conditions was carried out for eight feruloyl esterase preparations. Feruloyl esterases are a very important enzyme group in the valorization of lignocellulosic biomass, since they act in a synergistic way with other enzymes for the breakdown of plant biomass. Specifically, we investigated the type and concentration of precipitant and the crosslinker concentration, for retaining optimal activity. FAE68 was found to be the most promising enzyme for CLEA immobilization, since in this case, the maximum retained activity, over 98%, was observed. Subsequently, we examined the operational stability and the stability in organic solvents for the obtained CLEA preparations, as well as their structure. Overall, our results support that the maximum activity retaining and the stability properties of the final CLEAs can vary greatly in different FAE preparations. Nevertheless, some of the examined FAEs show a significant potential for further applications in harsh industrial conditions.

Place, publisher, year, edition, pages
MDPI, 2018
National Category
Chemical Engineering Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-68931 (URN)10.3390/catal8050208 (DOI)000435191500037 ()2-s2.0-85048056816 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-06-05 (rokbeg)

Available from: 2018-05-28 Created: 2018-05-28 Last updated: 2018-06-28Bibliographically approved
Zerva, A., Antonopoulou, I., Enman, J., Iancu, L., Jütten, P., Rova, U. & Christakopoulos, P. (2018). Optimization of Transesterification Reactions with CLEA-Immobilized Feruloyl Esterases from Thermothelomyces thermophila and Talaromyces wortmannii. Molecules, 23(9), Article ID 2403.
Open this publication in new window or tab >>Optimization of Transesterification Reactions with CLEA-Immobilized Feruloyl Esterases from Thermothelomyces thermophila and Talaromyces wortmannii
Show others...
2018 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 23, no 9, article id 2403Article in journal (Refereed) Published
Abstract [en]

Feruloyl esterases (FAEs, E.C. 3.1.1.73) are biotechnologically important enzymes with several applications in ferulic acid production from biomass, but also in synthesis of hydroxycinnamic acid derivatives. The use of such biocatalysts in commercial processes can become feasible by their immobilization, providing the advantages of isolation and recycling. In this work, eight feruloyl esterases, immobilized in cross-linked enzyme aggregates (CLEAs) were tested in regard to their transesterification performance, towards the production of prenyl ferulate (PFA) and arabinose ferulate (AFA). After solvent screening, comparison with the activity of respective soluble enzymes, and operational stability tests, FAE125 was selected as the most promising biocatalyst. A central composite design revealed the optimum conditions for each transesterification product, in terms of water content, time, and substrate ratio for both products, and temperature and enzyme load additionally for prenyl ferulate. The optimum product yields obtained were 83.7% for PFA and 58.1% for AFA. FAE125 CLEAs are stable in the optimum conditions of transesterification reactions, maintaining 70% residual activity after five consecutive reactions. Overall, FAE125 CLEAs seem to be able to perform as a robust biocatalyst, offering satisfactory yields and stability, and thus showing significant potential for industrial applications.

Place, publisher, year, edition, pages
MDPI, 2018
National Category
Other Industrial Biotechnology Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-70930 (URN)10.3390/molecules23092403 (DOI)30235900 (PubMedID)
Note

Validerad;2018;Nivå 2;2018-09-25 (svasva)

Available from: 2018-09-20 Created: 2018-09-20 Last updated: 2018-10-10Bibliographically approved
Zerva, A., Zervakis, G. I., Christakopoulos, P. & Topakas, E. (2017). Degradation of olive mill wastewater by the induced extracellular ligninolytic enzymes of two wood-rot fungi (ed.). Paper presented at 3rd International Conference on Sustainable Solid Waste Management, Greece, 2-4 July 2015. Journal of Environmental Management, 203:2, 791-798
Open this publication in new window or tab >>Degradation of olive mill wastewater by the induced extracellular ligninolytic enzymes of two wood-rot fungi
2017 (English)In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 203:2, p. 791-798Article in journal (Refereed) Published
Abstract [en]

Olive mill wastewater (OMWW) is a major problem in olive oil – producing countries, due to its high organic load and concentration in phenols that are toxic for marine life, plants and soil microorganisms. In the present study, two mushroom species were tested in regard to their OMWW's oxidative capacity, Pleurotus citrinopileatus LGAM 28684 and Irpex lacteus LGAM 238. OMWW (25% v/v) degradation was investigated for several culture conditions, namely pH, agitation speed, nitrogen-based supplements and their concentration. The selected values were pH 6, agitation rate 150 rpm, 30 g L−1 corn steep liquor as nitrogen source for P. citrinopileatus and 20 g L−1 diammonium tartrate for I. lacteus. The two strains performed well in cultures supplemented with OMWW, generating very high titers of oxidative enzymes and achieving more than 90% color and phenols reduction within a 24 days cultivation period. In addition, the amount of glucans present in the fungal biomass was assessed. Hence, P. citrinopileatus and I. lacteus appear as potent degraders of OMWW with the ability to use the effluent as a substrate for the production of biotechnologically important enzymes and valuable fungal glucans. 

Place, publisher, year, edition, pages
Elsevier, 2017
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-11664 (URN)10.1016/j.jenvman.2016.02.042 (DOI)000412621000023 ()26947318 (PubMedID)2-s2.0-84959280037 (Scopus ID)aad25b1f-e9bb-43dd-9bc5-f7a830bc8d91 (Local ID)aad25b1f-e9bb-43dd-9bc5-f7a830bc8d91 (Archive number)aad25b1f-e9bb-43dd-9bc5-f7a830bc8d91 (OAI)
Conference
3rd International Conference on Sustainable Solid Waste Management, Greece, 2-4 July 2015
Note

Konferensartikel i tidskrift

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zerva, A., Papaspyridi, L. M., Christakopoulos, P. & Topakas, E. (2017). Valorization of Olive Mill Wastewater for the Production of β-glucans from Selected Basidiomycetes. Paper presented at 9th International Conference on the Environmental and Technical Implications of Construction with Alternative Materials (WASCON) - Resource Efficiency in Construction, Santander, Spain, Jun 10-12, 2015. Waste and Biomass Valorization, 8(5), 1721-1731
Open this publication in new window or tab >>Valorization of Olive Mill Wastewater for the Production of β-glucans from Selected Basidiomycetes
2017 (English)In: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265X, Vol. 8, no 5, p. 1721-1731Article in journal (Refereed) Published
Abstract [en]

Purpose

The aim of the present study was to investigate the feasibility of polysaccharides production by selected basidiomycetes in submerged culture. Olive mill wastewater (OMWW) was also tested as a potential substrate for polysaccharides production by mushroom strains, focusing on the simultaneous degradation and valorization of the waste material.

Methods

The tested strains were grown in two different substrates, and after biomass harvesting, polysaccharides were isolated using two different methods. The extracellular polysaccharides were isolated from the culture broth, with ethanol precipitation. The isolated fractions were partially characterized with FT-IR spectroscopy.

Results

All three strains performed well in both substrates. Maximum degradation performance of OMWW was achieved by Ganoderma lucidum, achieving 19.4% phenols reduction together with 47.56% decolorization. The extracellular polysaccharides (EPS) produced by all strains were found to be richer in total glucans during growth in semi-synthetic medium, compared to growth in OMWW-based medium. In regard to biomass polysaccharides, Pleurotus ostreatus biomass was found to be richer in glucans, reaching 8.68% (w/w) total glucan content when grown in semi-synthetic medium and 7.58% (w/w) when grown in OMWW-based medium. After purification of biomass polysaccharides with two methods, the fraction with the highest glucan content was found to be the one from G. lucidum after growth in semi-synthetic medium cultures, with 49.1% (w/w) total glucans. FT-IR spectra of the isolated samples revealed the bands corresponding to α- and β-glucosidic bonds, but also the existence of protein contamination.

Conclusions

Purification of biomass polysaccharides with two distinct methods revealed that α-amylase and Sevag treatments failed to remove completely α-glucans and proteins respectively, leading to the suggestion that these two steps could be omitted without significant impact. Moreover, the results imply that the valorization of OMWW might be feasible with the use of mushroom strains, leading to the production of important products, such as glucans.

Place, publisher, year, edition, pages
Springer, 2017
National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-62070 (URN)10.1007/s12649-017-9839-7 (DOI)000406399700029 ()2-s2.0-85011663073 (Scopus ID)
Conference
9th International Conference on the Environmental and Technical Implications of Construction with Alternative Materials (WASCON) - Resource Efficiency in Construction, Santander, Spain, Jun 10-12, 2015
Note

Konferensartikel i tidskrift

Available from: 2017-02-17 Created: 2017-02-17 Last updated: 2018-11-15Bibliographically approved
Zerva, A., Manos, N., Vouyiouka, S., Christakopoulos, P. & Topakas, E. (2016). Bioconversion of Biomass-Derived Phenols Catalyzed by Myceliophthora thermophila Laccase (ed.). Molecules, 21(5), Article ID 550.
Open this publication in new window or tab >>Bioconversion of Biomass-Derived Phenols Catalyzed by Myceliophthora thermophila Laccase
Show others...
2016 (English)In: Molecules, ISSN 1420-3049, E-ISSN 1420-3049, Vol. 21, no 5, article id 550Article in journal (Refereed) Published
Abstract [en]

Biomass-derived phenols have recently arisen as an attractive alternative for building blocks to be used in synthetic applications, due to their widespread availability as an abundant renewable resource. In the present paper, commercial laccase from the thermophilic fungus Myceliophthora thermophila was used to bioconvert phenol monomers, namely catechol, pyrogallol and gallic acid in water. The resulting products from catechol and gallic acid were polymers that were partially characterized in respect to their optical and thermal properties, and their average molecular weight was estimated via solution viscosity measurements and GPC. FT-IR and 1H-NMR data suggest that phenol monomers are connected with ether or C–C bonds depending on the starting monomer, while the achieved molecular weight of polycatechol is found higher than the corresponding poly(gallic acid). On the other hand, under the same condition, pyrogallol was dimerized in a pure red crystalline compound and its structure was confirmed by 1H-NMR as purpurogallin. The herein studied green synthesis of enzymatically synthesized phenol polymers or biological active compounds could be exploited as an alternative synthetic route targeting a variety of applications.

National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-2500 (URN)10.3390/molecules21050550 (DOI)000380241600015 ()27128897 (PubMedID)2-s2.0-85015024951 (Scopus ID)01e1fb1a-de6b-4d23-bd29-ff08bad896c0 (Local ID)01e1fb1a-de6b-4d23-bd29-ff08bad896c0 (Archive number)01e1fb1a-de6b-4d23-bd29-ff08bad896c0 (OAI)
Note

Validerad; 2016; Nivå 2; 20160502 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zerva, A., Christakopoulos, P. & Topekas, E. (2015). Characterization and application of a novel class II thermophilic peroxidase from Myceliophthora thermophila in biosynthesis of polycatechol (ed.). Enzyme and microbial technology, 75-76, 49-56
Open this publication in new window or tab >>Characterization and application of a novel class II thermophilic peroxidase from Myceliophthora thermophila in biosynthesis of polycatechol
2015 (English)In: Enzyme and microbial technology, ISSN 0141-0229, E-ISSN 1879-0909, Vol. 75-76, p. 49-56Article in journal (Refereed) Published
Abstract [en]

A peroxidase from the thermophilic fungus Myceliophthora thermophila that belongs to ascomycete Class II based on PeroxiBase classification was functionally expressed in methylotrophic yeast Pichia pastoris. The putative peroxidase from the genomic DNA was successfully cloned in P. pastoris X-33 under the transcriptional control of the alcohol oxidase (AOX1) promoter. The heterologous production was greatly enhanced by the addition of hemin with a titer of 0.41 U mL−1 peroxidase activity at the second day of incubation. The recombinant enzyme was purified to homogeneity (50 kDa) and characterized using a series of phenolic substrates that indicated similar characteristics with those of generic peroxidases. In addition, the enzyme was found thermostable, retaining its activity for temperatures up to 60 oC after eight hours incubation. Moreover, the enzyme displayed remarkable H2O2 stability, retaining more than 80% of its initial activity after 24 hours incubation in 5000- fold molar excess of H2O2. The ability of the peroxidase to polymerize catechol at high superoxide concentrations, together with its high thermostability and substrate specificity, indicate a potential commercial significance of the enzyme.

National Category
Bioprocess Technology
Research subject
Biochemical Process Engineering
Identifiers
urn:nbn:se:ltu:diva-4301 (URN)10.1016/j.enzmictec.2015.04.012 (DOI)000357145700008 ()26047916 (PubMedID)2-s2.0-84929649837 (Scopus ID)23c0db13-e657-42c1-a95a-225a301b7b29 (Local ID)23c0db13-e657-42c1-a95a-225a301b7b29 (Archive number)23c0db13-e657-42c1-a95a-225a301b7b29 (OAI)
Note

Validerad; 2015; Nivå 2; 20150511 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0361-7690

Search in DiVA

Show all publications