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Haddad Momeni M, Zitting A, Jäämuru V, Turunen R, Penttilä P, Buchko GW, Hiltunen S, Maiorova N, Koivula A, Sapkota J, Marjamaa K, Master ER. Insights into the action of phylogenetically diverse microbial expansins on the structure of cellulose microfibrils. Biotechnol Biofuels Bioprod 2024; 17:56. [PMID: 38654330 DOI: 10.1186/s13068-024-02500-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/04/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Microbial expansins (EXLXs) are non-lytic proteins homologous to plant expansins involved in plant cell wall formation. Due to their non-lytic cell wall loosening properties and potential to disaggregate cellulosic structures, there is considerable interest in exploring the ability of microbial expansins (EXLX) to assist the processing of cellulosic biomass for broader biotechnological applications. Herein, EXLXs with different modular structure and from diverse phylogenetic origin were compared in terms of ability to bind cellulosic, xylosic, and chitinous substrates, to structurally modify cellulosic fibrils, and to boost enzymatic deconstruction of hardwood pulp. RESULTS Five heterogeneously produced EXLXs (Clavibacter michiganensis; CmiEXLX2, Dickeya aquatica; DaqEXLX1, Xanthomonas sacchari; XsaEXLX1, Nothophytophthora sp.; NspEXLX1 and Phytophthora cactorum; PcaEXLX1) were shown to bind xylan and hardwood pulp at pH 5.5 and CmiEXLX2 (harboring a family-2 carbohydrate-binding module) also bound well to crystalline cellulose. Small-angle X-ray scattering revealed a 20-25% increase in interfibrillar distance between neighboring cellulose microfibrils following treatment with CmiEXLX2, DaqEXLX1, or NspEXLX1. Correspondingly, combining xylanase with CmiEXLX2 and DaqEXLX1 increased product yield from hardwood pulp by ~ 25%, while supplementing the TrAA9A LPMO from Trichoderma reesei with CmiEXLX2, DaqEXLX1, and NspEXLX1 increased total product yield by over 35%. CONCLUSION This direct comparison of diverse EXLXs revealed consistent impacts on interfibrillar spacing of cellulose microfibers and performance of carbohydrate-active enzymes predicted to act on fiber surfaces. These findings uncover new possibilities to employ EXLXs in the creation of value-added materials from cellulosic biomass.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
| | - Aleksi Zitting
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Vilma Jäämuru
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Rosaliina Turunen
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Paavo Penttilä
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland
| | - Garry W Buchko
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, 99354, USA
- School of Molecular Biosciences, Washington State University, Pullman, WA, 99164, USA
| | - Salla Hiltunen
- NE Research Center, UPM Pulp Research and Innovations, 53200, Lappeenranta, Finland
| | - Natalia Maiorova
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044-VTT, Espoo, Finland
| | - Anu Koivula
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044-VTT, Espoo, Finland
| | - Janak Sapkota
- NE Research Center, UPM Pulp Research and Innovations, 53200, Lappeenranta, Finland
| | - Kaisa Marjamaa
- VTT Technical Research Centre of Finland Ltd, P.O. Box 1000, 02044-VTT, Espoo, Finland
| | - Emma R Master
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150, Espoo, Finland.
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada.
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Dahiya D, Koitto T, Kutvonen K, Wang Y, Haddad Momeni M, de Ruijter S, Master ER. Fungal loosenin-like proteins boost the cellulolytic enzyme conversion of pretreated wood fiber and cellulosic pulps. Bioresour Technol 2024; 394:130188. [PMID: 38104665 DOI: 10.1016/j.biortech.2023.130188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/19/2023]
Abstract
Microbial expansin-related proteins, including loosenins, can disrupt cellulose networks and increase enzyme accessibility to cellulosic substrates. Herein, four loosenins from Phanerochaete carnosa (PcaLOOLs), and a PcaLOOL fused to a family 63 carbohydrate-binding module, were compared for ability to boost the cellulolytic deconstruction of steam pretreated softwood (SSW) and kraft pulps from softwood (ND-BSKP) and hardwood (ND-BHKP). Amending the Cellic® CTec-2 cellulase cocktail with PcaLOOLs increased reducing products from SSW by up to 40 %, corresponding to 28 % higher glucose yield. Amending Cellic® CTec-2 with PcaLOOLs also increased the release of glucose from ND-BSKP and ND-BHKP by 82 % and 28 %, respectively. Xylose release from ND-BSKP and ND-BHKP increased by 47 % and 57 %, respectively, highlighting the potential of PcaLOOLs to enhance hemicellulose recovery. Scanning electron microscopy and fiber image analysis revealed fibrillation and curlation of ND-BSKP after PcaLOOL treatment, consistent with increasing enzyme accessibility to targeted substrates.
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Affiliation(s)
- Deepika Dahiya
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Taru Koitto
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Kim Kutvonen
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Yan Wang
- Biorefining Business Development & Production, St1 Oy, Firdonkatu 2, 00520 Helsinki, Finland
| | - Majid Haddad Momeni
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Siiri de Ruijter
- Biorefining Business Development & Production, St1 Oy, Firdonkatu 2, 00520 Helsinki, Finland
| | - Emma R Master
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, M5S 3E5 Toronto, Ontario, Canada.
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3
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Haataja T, Gado JE, Nutt A, Anderson NT, Nilsson M, Momeni MH, Isaksson R, Väljamäe P, Johansson G, Payne CM, Ståhlberg J. Enzyme kinetics by GH7 cellobiohydrolases on chromogenic substrates is dictated by non-productive binding: insights from crystal structures and MD simulation. FEBS J 2023; 290:379-399. [PMID: 35997626 PMCID: PMC10087753 DOI: 10.1111/febs.16602] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/30/2022] [Accepted: 08/17/2022] [Indexed: 02/05/2023]
Abstract
Cellobiohydrolases (CBHs) in the glycoside hydrolase family 7 (GH7) (EC3.2.1.176) are the major cellulose degrading enzymes both in industrial settings and in the context of carbon cycling in nature. Small carbohydrate conjugates such as p-nitrophenyl-β-d-cellobioside (pNPC), p-nitrophenyl-β-d-lactoside (pNPL) and methylumbelliferyl-β-d-cellobioside have commonly been used in colorimetric and fluorometric assays for analysing activity of these enzymes. Despite the similar nature of these compounds the kinetics of their enzymatic hydrolysis vary greatly between the different compounds as well as among different enzymes within the GH7 family. Through enzyme kinetics, crystallographic structure determination, molecular dynamics simulations, and fluorometric binding studies using the closely related compound o-nitrophenyl-β-d-cellobioside (oNPC), in this work we examine the different hydrolysis characteristics of these compounds on two model enzymes of this class, TrCel7A from Trichoderma reesei and PcCel7D from Phanerochaete chrysosporium. Protein crystal structures of the E212Q mutant of TrCel7A with pNPC and pNPL, and the wildtype TrCel7A with oNPC, reveal that non-productive binding at the product site is the dominating binding mode for these compounds. Enzyme kinetics results suggest the strength of non-productive binding is a key determinant for the activity characteristics on these substrates, with PcCel7D consistently showing higher turnover rates (kcat ) than TrCel7A, but higher Michaelis-Menten (KM ) constants as well. Furthermore, oNPC turned out to be useful as an active-site probe for fluorometric determination of the dissociation constant for cellobiose on TrCel7A but could not be utilized for the same purpose on PcCel7D, likely due to strong binding to an unknown site outside the active site.
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Affiliation(s)
- Topi Haataja
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Japheth E Gado
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA.,Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Anu Nutt
- Department of Chemistry, Uppsala University, Sweden.,Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | - Nolan T Anderson
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Mikael Nilsson
- Institute of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Majid Haddad Momeni
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Roland Isaksson
- Institute of Chemistry and Biomedical Sciences, Linnaeus University, Kalmar, Sweden
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Estonia
| | | | - Christina M Payne
- Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY, USA
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Haddad Momeni M, Leth ML, Sternberg C, Schoof E, Nielsen MW, Holck J, Workman CT, Hoof JB, Abou Hachem M. Loss of AA13 LPMOs impairs degradation of resistant starch and reduces the growth of Aspergillus nidulans. Biotechnol Biofuels 2020; 13:135. [PMID: 32774456 PMCID: PMC7405360 DOI: 10.1186/s13068-020-01775-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Lytic polysaccharide monooxygenases (LPMOs) are often studied in simple models involving activity measurements of a single LPMO or a blend thereof with hydrolytic enzymes towards an insoluble substrate. However, the contribution of LPMOs to polysaccharide breakdown in complex cocktails of hydrolytic and oxidative enzymes, similar to fungal secretomes, remains elusive. Typically, two starch-specific AA13 LPMOs are encoded by mainly Ascomycota genomes. Here, we investigate the impact of LPMO loss on the growth and degradation of starches of varying resistance to amylolytic hydrolases by Aspergillus nidulans. RESULTS Deletion of the genes encoding AnAA13A that possesses a CBM20 starch-binding module, AnAA13B (lacking a CBM20) or both AA13 genes resulted in reduced growth on solid media with resistant, but not soluble processed potato starch. Larger size and amount of residual starch granules were observed for the AA13-deficient strains as compared to the reference and the impairment of starch degradation was more severe for the strain lacking AnAA13A based on a microscopic analysis. After 5 days of growth on raw potato starch in liquid media, the mount of residual starch was about fivefold higher for the AA13 gene deletion strains compared to the reference, which underscores the importance of LPMOs for degradation of especially resistant starches. Proteomic analyses revealed substantial changes in the secretomes of the double AA13 gene deletion, followed by the AnAA13A-deficient strain, whereas only a single protein was significantly different in the proteome of the AnAA13B-deficient strain as compared to the reference. CONCLUSIONS This study shows that the loss of AA13, especially the starch-binding AnAA13A, impairs degradation of resistant potato starch, but has limited impact on less-resistant wheat starch and no impact on processed solubilized starch. The effects of LPMO loss are more pronounced at the later stages of fungal growth, likely due to the accumulation of the less-accessible regions of the substrate. The striking impairment in granular starch degradation due to the loss of a single LPMO from the secretome offers insight into the crucial role played by AA13 in the breakdown of resistant starch and presents a methodological framework to analyse the contribution of distinct LPMOs towards semi-crystalline polysaccharides under in vivo conditions.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Maria Louise Leth
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Claus Sternberg
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Erwin Schoof
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Maike Wennekers Nielsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Jesper Holck
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Christopher T. Workman
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Jakob Blæsbjerg Hoof
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
| | - Maher Abou Hachem
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs. Lyngby, Denmark
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Haddad Momeni M, Bollella P, Ortiz R, Thormann E, Gorton L, Abou Hachem M. A novel starch-binding laccase from the wheat pathogen Zymoseptoria tritici highlights the functional diversity of ascomycete laccases. BMC Biotechnol 2019; 19:61. [PMID: 31426777 PMCID: PMC6700816 DOI: 10.1186/s12896-019-0552-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 07/26/2019] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Laccases are multicopper oxidases, which are assigned into auxiliary activity family 1 (AA1) in the CAZy database. These enzymes, catalyzing the oxidation of phenolic and nonphenolic substrates coupled to reduction of O2 to H2O, are increasingly attractive as eco-friendly oxidation biocatalysts. Basidiomycota laccases are well characterized due to their potential in de-lignification of lignocellulose. By contrast, insight into the biochemical diversity of Ascomycota counterparts from saprophytes and plant pathogens is scarce. RESULTS Here, we report the properties of the laccase from the major wheat pathogen Zymoseptoria tritici (ZtrLac1A), distinguished from common plant fungal pathogens by an apoplastic infection strategy. We demonstrate that ZtrLac1A is appended to a functional starch-binding module and displays an activity signature disfavoring relatively apolar phenolic redox mediators as compared to the related biochemically characterized laccases. By contrast, the redox potential of ZtrLac1A (370 mV vs. SHE) is similar to ascomycetes counterparts. The atypical specificity is consistent with distinctive sequence substitutions and insertions in loops flanking the T1 site and the enzyme C-terminus compared to characterized laccases. CONCLUSIONS ZtrLac1A is the first reported modular laccase appended to a functional starch-specific carbohydrate binding module of family 20 (CBM20). The distinct specificity profile of ZtrLac1A correlates to structural differences in the active site region compared to previously described ascomycetes homologues. These differences are also highlighted by the clustering of the sequence of ZtrLac1A in a distinct clade populated predominantly by plant pathogens in the phylogenetic tree of AA1 laccases. The possible role of these laccases in vivo merits further investigations. These findings expand our toolbox of laccases for green oxidation and highlight the binding functionality of CBM-appended laccases as versatile immobilization tags.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark
| | - Paolo Bollella
- Department of Biochemistry and Structural Biology, Lund University, P.O. Box 124, 221 00 Lund, Sweden
- Department of Chemistry and Drug Technologies, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Roberto Ortiz
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs, Lyngby, Denmark
| | - Esben Thormann
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs, Lyngby, Denmark
| | - Lo Gorton
- Department of Biochemistry and Structural Biology, Lund University, P.O. Box 124, 221 00 Lund, Sweden
| | - Maher Abou Hachem
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs, Lyngby, Denmark
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Momeni MH, Ubhayasekera W, Sandgren M, Ståhlberg J, Hansson H. Structural insights into the inhibition of cellobiohydrolase Cel7A by xylo-oligosaccharides. FEBS J 2015; 282:2167-77. [PMID: 25765184 DOI: 10.1111/febs.13265] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED The filamentous fungus Hypocrea jecorina (anamorph of Trichoderma reesei) is the predominant source of enzymes for industrial saccharification of lignocellulose biomass. The major enzyme, cellobiohydrolase Cel7A, constitutes nearly half of the total protein in the secretome. The performance of such enzymes is susceptible to inhibition by compounds liberated by physico-chemical pre-treatment if the biomass is kept unwashed. Xylan and xylo-oligosaccharides (XOS) have been proposed to play a key role in inhibition of cellobiohydrolases of glycoside hydrolase family 7. To elucidate the mechanism behind this inhibition at a molecular level, we used X-ray crystallography to determine structures of H. jecorina Cel7A in complex with XOS. Structures with xylotriose, xylotetraose and xylopentaose revealed a predominant binding mode at the entrance of the substrate-binding tunnel of the enzyme, in which each xylose residue is shifted ~ 2.4 Å towards the catalytic center compared with binding of cello-oligosaccharides. Furthermore, partial occupancy of two consecutive xylose residues at subsites -2 and -1 suggests an alternative binding mode for XOS in the vicinity of the catalytic center. Interestingly, the -1 xylosyl unit exhibits an open aldehyde conformation in one of the structures and a ring-closed pyranoside in another complex. Complementary inhibition studies with p-nitrophenyl lactoside as substrate indicate mixed inhibition rather than pure competitive inhibition. DATABASE The atomic coordinates and structure factors are available in the Protein Data Bank under accession number 4D5I (H. jecorina Cel7A E212Q variant, complex with xylotriose), 4D5J (H. jecorina Cel7A E217Q variant, complex with xylotriose), 4D5O (H. jecorina Cel7A E212Q variant, complex with xylopentaose), 4D5P (H. jecorina Cel7A E217Q variant, complex with xylopentaose), 4D5Q (wild-type H. jecorina Cel7A, complex with xylopentaose) and 4D5V (H. jecorina Cel7A E217Q variant, complex with xylotetraose).
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Affiliation(s)
- Majid Haddad Momeni
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Wimal Ubhayasekera
- Institute of Medicinal Chemistry, University of Copenhagen, Denmark.,MAX-Lab, Lund University, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Henrik Hansson
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Tiukova IA, de Barros Pita W, Sundell D, Haddad Momeni M, Horn SJ, Ståhlberg J, de Morais MA, Passoth V. Adaptation of Dekkera bruxellensis to lignocellulose-based substrate. Biotechnol Appl Biochem 2014; 61:51-7. [PMID: 23941546 DOI: 10.1002/bab.1145] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Accepted: 07/18/2013] [Indexed: 11/10/2022]
Abstract
Adaptation of Dekkera bruxellensis to lignocellulose hydrolysate was investigated. Cells of D. bruxellensis were grown for 72 and 192 H in batch and continuous culture, respectively (adapted cells). Cultivations in semisynthetic medium were run as controls (nonadapted cells). To test the adaptation, cells from these cultures were reinoculated in the lignocellulose medium, and growth and ethanol production characteristics were monitored. Cells adapted to lignocellulose hydrolysate had a shorter lag phase, grew faster, and produced a higher ethanol concentration as compared with nonadapted cells. A stability test showed that after cultivation in rich medium, cells partially lost the adapted phenotype but still showed faster growth and higher ethanol production as compared with nonadapted cells. Because alcohol dehydrogenase genes have been described to be involved in the adaptation to furfural in Saccharomyces cerevisiae, an analogous mechanism of adaptation to lignocelluloses hydrolysate of D. bruxellensis was hypothesized. However, gene expression analysis showed that genes homologous to S. cerevisiae ADH1 were not involved in the adaptation to lignocelluloses hydrolysate in D. bruxellensis.
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Affiliation(s)
- Ievgeniia A Tiukova
- Uppsala Biocenter, Department of Microbiology, Swedish University of Agricultural Sciences, Box 7025750 07, Uppsala, Sweden
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Momeni MH, Goedegebuur F, Hansson H, Karkehabadi S, Askarieh G, Mitchinson C, Larenas EA, Ståhlberg J, Sandgren M. Expression, crystal structure and cellulase activity of the thermostable cellobiohydrolase Cel7A from the fungus Humicola grisea var. thermoidea. Acta Crystallogr D Biol Crystallogr 2014; 70:2356-66. [PMID: 25195749 PMCID: PMC4157447 DOI: 10.1107/s1399004714013844] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/13/2014] [Indexed: 11/11/2022]
Abstract
Glycoside hydrolase family 7 (GH7) cellobiohydrolases (CBHs) play a key role in biomass recycling in nature. They are typically the most abundant enzymes expressed by potent cellulolytic fungi, and are also responsible for the majority of hydrolytic potential in enzyme cocktails for industrial processing of plant biomass. The thermostability of the enzyme is an important parameter for industrial utilization. In this study, Cel7 enzymes from different fungi were expressed in a fungal host and assayed for thermostability, including Hypocrea jecorina Cel7A as a reference. The most stable of the homologues, Humicola grisea var. thermoidea Cel7A, exhibits a 10°C higher melting temperature (T(m) of 72.5°C) and showed a 4-5 times higher initial hydrolysis rate than H. jecorina Cel7A on phosphoric acid-swollen cellulose and showed the best performance of the tested enzymes on pretreated corn stover at elevated temperature (65°C, 24 h). The enzyme shares 57% sequence identity with H. jecorina Cel7A and consists of a GH7 catalytic module connected by a linker to a C-terminal CBM1 carbohydrate-binding module. The crystal structure of the H. grisea var. thermoidea Cel7A catalytic module (1.8 Å resolution; R(work) and R(free) of 0.16 and 0.21, respectively) is similar to those of other GH7 CBHs. The deviations of several loops along the cellulose-binding path between the two molecules in the asymmetric unit indicate higher flexibility than in the less thermostable H. jecorina Cel7A.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Frits Goedegebuur
- DuPont, Industrial Biosciences, Archimedesweg 30, 2333 CN Leiden, The Netherlands
| | - Henrik Hansson
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Saeid Karkehabadi
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Glareh Askarieh
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Colin Mitchinson
- DuPont, Industrial Biosciences, Page Mill Road, Palo Alto, CA 94304, USA
| | - Edmundo A. Larenas
- DuPont, Industrial Biosciences, Page Mill Road, Palo Alto, CA 94304, USA
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, PO Box 7015, SE-750 07 Uppsala, Sweden
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Knott BC, Haddad Momeni M, Crowley MF, Mackenzie LF, Götz AW, Sandgren M, Withers SG, Ståhlberg J, Beckham GT. The Mechanism of Cellulose Hydrolysis by a Two-Step, Retaining Cellobiohydrolase Elucidated by Structural and Transition Path Sampling Studies. J Am Chem Soc 2013; 136:321-9. [DOI: 10.1021/ja410291u] [Citation(s) in RCA: 141] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
| | - Majid Haddad Momeni
- Department
of Molecular Biology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | | | - Lloyd F. Mackenzie
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Andreas W. Götz
- San
Diego Supercomputer Center, University of California San Diego, La Jolla, California 92093, United States
| | - Mats Sandgren
- Department
of Molecular Biology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
| | - Stephen G. Withers
- Department
of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z1
| | - Jerry Ståhlberg
- Department
of Molecular Biology, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden
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Momeni MH, Payne CM, Hansson H, Mikkelsen NE, Svedberg J, Engström Å, Sandgren M, Beckham GT, Ståhlberg J. Structural, biochemical, and computational characterization of the glycoside hydrolase family 7 cellobiohydrolase of the tree-killing fungus Heterobasidion irregulare. J Biol Chem 2013; 288:5861-72. [PMID: 23303184 DOI: 10.1074/jbc.m112.440891] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Root rot fungi of the Heterobasidion annosum complex are the most damaging pathogens in temperate forests, and the recently sequenced Heterobasidion irregulare genome revealed over 280 carbohydrate-active enzymes. Here, H. irregulare was grown on biomass, and the most abundant protein in the culture filtrate was identified as the only family 7 glycoside hydrolase in the genome, which consists of a single catalytic domain, lacking a linker and carbohydrate-binding module. The enzyme, HirCel7A, was characterized biochemically to determine the optimal conditions for activity. HirCel7A was crystallized and the structure, refined at 1.7 Å resolution, confirms that HirCel7A is a cellobiohydrolase rather than an endoglucanase, with a cellulose-binding tunnel that is more closed than Phanerochaete chrysosporium Cel7D and more open than Hypocrea jecorina Cel7A, suggesting intermediate enzyme properties. Molecular simulations were conducted to ascertain differences in enzyme-ligand interactions, ligand solvation, and loop flexibility between the family 7 glycoside hydrolase cellobiohydrolases from H. irregulare, H. jecorina, and P. chrysosporium. The structural comparisons and simulations suggest significant differences in enzyme-ligand interactions at the tunnel entrance in the -7 to -4 binding sites and suggest that a tyrosine residue at the tunnel entrance of HirCel7A may serve as an additional ligand-binding site. Additionally, the loops over the active site in H. jecorina Cel7A are more closed than loops in the other two enzymes, which has implications for the degree of processivity, endo-initiation, and substrate dissociation. Overall, this study highlights molecular level features important to understanding this biologically and industrially important family of glycoside hydrolases.
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Affiliation(s)
- Majid Haddad Momeni
- Department of Molecular Biology, Swedish University of Agricultural Sciences, SE-751 24 Uppsala, Sweden
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Blomqvist J, South E, Tiukova I, Tiukova L, Momeni MH, Hansson H, Ståhlberg J, Horn SJ, Schnürer J, Passoth V. Fermentation of lignocellulosic hydrolysate by the alternative industrial ethanol yeast Dekkera bruxellensis. Lett Appl Microbiol 2011; 53:73-8. [PMID: 21535044 DOI: 10.1111/j.1472-765x.2011.03067.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM Testing the ability of the alternative ethanol production yeast Dekkera bruxellensis to produce ethanol from lignocellulose hydrolysate and comparing it to Saccharomyces cerevisiae. METHODS AND RESULTS Industrial isolates of D. bruxellensis and S. cerevisiae were cultivated in small-scale batch fermentations of enzymatically hydrolysed steam exploded aspen sawdust. Different dilutions of hydrolysate were tested. None of the yeasts grew in undiluted or 1:2 diluted hydrolysate [final glucose concentration always adjusted to 40 g l⁻¹ (0.22 mol l⁻¹)]. This was most likely due to the presence of inhibitors such as acetate or furfural. In 1:5 hydrolysate, S. cerevisiae grew, but not D. bruxellensis, and in 1:10 hydrolysate, both yeasts grew. An external vitamin source (e.g. yeast extract) was essential for growth of D. bruxellensis in this lignocellulosic hydrolysate and strongly stimulated S. cerevisiae growth and ethanol production. Ethanol yields of 0.42 ± 0.01 g ethanol (g glucose)⁻¹ were observed for both yeasts in 1:10 hydrolysate. In small-scale continuous cultures with cell recirculation, with a gradual increase in the hydrolysate concentration, D. bruxellensis was able to grow in 1:5 hydrolysate. In bioreactor experiments with cell recirculation, hydrolysate contents were increased up to 1:2 hydrolysate, without significant losses in ethanol yields for both yeasts and only slight differences in viable cell counts, indicating an ability of both yeasts to adapt to toxic compounds in the hydrolysate. CONCLUSIONS Dekkera bruxellensis and S. cerevisiae have a similar potential to ferment lignocellulose hydrolysate to ethanol and to adapt to fermentation inhibitors in the hydrolysate. SIGNIFICANCE AND IMPACT OF THE STUDY This is the first study investigating the potential of D. bruxellensis to ferment lignocellulosic hydrolysate. Its high competitiveness in industrial fermentations makes D. bruxellensis an interesting alternative for ethanol production from those substrates.
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Affiliation(s)
- J Blomqvist
- Department of Microbiology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Uppsala, Sweden.
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Dererie DY, Trobro S, Momeni MH, Hansson H, Blomqvist J, Passoth V, Schnürer A, Sandgren M, Ståhlberg J. Improved bio-energy yields via sequential ethanol fermentation and biogas digestion of steam exploded oat straw. Bioresour Technol 2011; 102:4449-55. [PMID: 21256738 DOI: 10.1016/j.biortech.2010.12.096] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 12/22/2010] [Accepted: 12/23/2010] [Indexed: 05/11/2023]
Abstract
Using standard laboratory equipment, thermochemically pretreated oat straw was enzymatically saccharified and fermented to ethanol, and after removal of ethanol the remaining material was subjected to biogas digestion. A detailed mass balance calculation shows that, for steam explosion pretreatment, this combined ethanol fermentation and biogas digestion converts 85-87% of the higher heating value (HHV) of holocellulose (cellulose and hemicellulose) in the oat straw into biofuel energy. The energy (HHV) yield of the produced ethanol and methane was 9.5-9.8 MJ/(kg dry oat straw), which is 28-34% higher than direct biogas digestion that yielded 7.3-7.4 MJ/(kg dry oat straw). The rate of biogas formation from the fermentation residues was also higher than from the corresponding pretreated but unfermented oat straw, indicating that the biogas digestion could be terminated after only 24 days. This suggests that the ethanol process acts as an additional pretreatment for the biogas process.
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Affiliation(s)
- Debebe Yilma Dererie
- Department of Molecular Biology, Swedish University of Agricultural Sciences, P.O. Box 590, SE-751 24 Uppsala, Sweden
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Andersen AC, Hendrickx AG, Momeni MH. Factionated X-radiation damage to developing ovaries in the bonnet monkey (Macaca radiata). Radiat Res 1977; 71:398-405. [PMID: 408865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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14
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Momeni MH, Jow N, Bradley E, Dunford P. Measurement of bone density by gas displacement. Biomed Eng 1976; 11:211-3. [PMID: 949514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Small bone volumes, porous and irregular structured objects with volumes 0.05-2 cm3, were measured by differential pressure of displaced air. The differential air pressure was measured by a piezoelectric resistor pressure gauge. The gas-displacement system was used to measure the volumes of 234 bone specimens for calculation of bone density. The operation of the system, calibration, sensitivity, and errors of measurement are described.
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Momeni MH, Cahill TA, Horn PL. Proton irradiation of beagle eyes. I. Si(Li) and thermoluminescent dosimetry of 20, 35, and 45 MeV protons. Radiat Res 1973; 53:15-23. [PMID: 4685478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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