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Dziemianowicz W, Kotarska K, Świerczyńska A. The Effect of Technological Conditions on ABE Fermentation and Butanol Production of Rye Straw and the Composition of Volatile Compounds. Molecules 2024; 29:3398. [PMID: 39064975 PMCID: PMC11280078 DOI: 10.3390/molecules29143398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/15/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
The objective of this study was to evaluate the effect of pretreatment and different technological conditions on the course of ABE fermentation of rye straw (RS) and the composition of volatile compounds in the distillates obtained. The highest concentration of ABE and butanol was obtained from the fermentation of pretreated rye straw by alkaline hydrolysis followed by detoxification and enzymatic hydrolysis. After 72 h of fermentation, the maximum butanol concentration, productivity, and yield from RS were 16.11 g/L, 0.224 g/L/h, and 0.402 g/g, respectively. Three different methods to produce butanol were tested: the two-step process (SHF), the simultaneous process (SSF), and simultaneous saccharification with ABE fermentation (consolidation SHF/SSF). The SHF/SSF process observed that ABE concentration (21.28 g/L) was higher than in the SSF (20.03 g/L) and lower compared with the SHF (22.21 g/L). The effect of the detoxification process and various ABE fermentation technologies on the composition of volatile compounds formed during fermentation and distillation were analyzed.
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Affiliation(s)
- Wojciech Dziemianowicz
- Department of Distillery Technology and Renewable Energy, Prof. Wacław Dąbrowski Institute of Agriculture and Food Biotechnology—State Research Institute, Powstańców Wielkopolskich 17, 85-090 Bydgoszcz, Poland; (K.K.); (A.Ś.)
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de Assis MA, da Silva JJB, de Carvalho LM, Parreiras LS, Cairo JPLF, Marone MP, Gonçalves TA, Silva DS, Dantzger M, de Figueiredo FL, Carazzolle MF, Pereira GAG, Damasio A. A Multiomics Perspective on Plant Cell Wall-Degrading Enzyme Production: Insights from the Unexploited Fungus Trichoderma erinaceum. J Fungi (Basel) 2024; 10:407. [PMID: 38921393 PMCID: PMC11205114 DOI: 10.3390/jof10060407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/27/2024] Open
Abstract
Trichoderma erinaceum is a filamentous fungus that was isolated from decaying sugarcane straw at a Brazilian ethanol biorefinery. This fungus shows potential as a source of plant cell wall-degrading enzymes (PCWDEs). In this study, we conducted a comprehensive multiomics investigation of T. erinaceum to gain insights into its enzymatic capabilities and genetic makeup. Firstly, we performed genome sequencing and assembly, which resulted in the identification of 10,942 genes in the T. erinaceum genome. We then conducted transcriptomics and secretome analyses to map the gene expression patterns and identify the enzymes produced by T. erinaceum in the presence of different substrates such as glucose, microcrystalline cellulose, pretreated sugarcane straw, and pretreated energy cane bagasse. Our analyses revealed that T. erinaceum highly expresses genes directly related to lignocellulose degradation when grown on pretreated energy cane and sugarcane substrates. Furthermore, our secretome analysis identified 35 carbohydrate-active enzymes, primarily PCWDEs. To further explore the enzymatic capabilities of T. erinaceum, we selected a β-glucosidase from the secretome data for recombinant production in a fungal strain. The recombinant enzyme demonstrated superior performance in degrading cellobiose and laminaribiose compared to a well-known enzyme derived from Trichoderma reesei. Overall, this comprehensive study provides valuable insights into both the genetic patterns of T. erinaceum and its potential for lignocellulose degradation and enzyme production. The obtained genomic data can serve as an important resource for future genetic engineering efforts aimed at optimizing enzyme production from this fungus.
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Affiliation(s)
- Michelle A. de Assis
- Laboratory of Enzymology and Molecular Biology (LEBIMO), Department of Biochemistry and Tissue Biology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (M.A.d.A.); (J.P.L.F.C.); (T.A.G.); (F.L.d.F.)
| | - Jovanderson J. B. da Silva
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - Lucas M. de Carvalho
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - Lucas S. Parreiras
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - João Paulo L. F. Cairo
- Laboratory of Enzymology and Molecular Biology (LEBIMO), Department of Biochemistry and Tissue Biology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (M.A.d.A.); (J.P.L.F.C.); (T.A.G.); (F.L.d.F.)
- York Structural Biology Laboratory (YSBL), Department of Chemistry, University of York, York YO10 5DD, UK
| | - Marina P. Marone
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - Thiago A. Gonçalves
- Laboratory of Enzymology and Molecular Biology (LEBIMO), Department of Biochemistry and Tissue Biology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (M.A.d.A.); (J.P.L.F.C.); (T.A.G.); (F.L.d.F.)
| | - Desireé S. Silva
- SENAI Institute for Biomass Innovation, Três Lagoas 79640-250, Brazil;
| | - Miriam Dantzger
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - Fernanda L. de Figueiredo
- Laboratory of Enzymology and Molecular Biology (LEBIMO), Department of Biochemistry and Tissue Biology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (M.A.d.A.); (J.P.L.F.C.); (T.A.G.); (F.L.d.F.)
| | - Marcelo F. Carazzolle
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - Gonçalo A. G. Pereira
- Genomics and BioEnergy Laboratory (LGE), Department of Genetics, Evolution, Microbiology and Immunology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (J.J.B.d.S.); (L.M.d.C.); (L.S.P.); (M.D.); (M.F.C.); (G.A.G.P.)
| | - André Damasio
- Laboratory of Enzymology and Molecular Biology (LEBIMO), Department of Biochemistry and Tissue Biology, Universidade Estadual de Campinas (UNICAMP), Campinas 13083-862, São Paulo, Brazil; (M.A.d.A.); (J.P.L.F.C.); (T.A.G.); (F.L.d.F.)
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Nong D, Haviland ZK, Zexer N, Pfaff SA, Cosgrove DJ, Tien M, Anderson CT, Hancock WO. Single-molecule tracking reveals dual front door/back door inhibition of Cel7A cellulase by its product cellobiose. Proc Natl Acad Sci U S A 2024; 121:e2322567121. [PMID: 38648472 PMCID: PMC11067010 DOI: 10.1073/pnas.2322567121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/18/2024] [Indexed: 04/25/2024] Open
Abstract
Degrading cellulose is a key step in the processing of lignocellulosic biomass into bioethanol. Cellobiose, the disaccharide product of cellulose degradation, has been shown to inhibit cellulase activity, but the mechanisms underlying product inhibition are not clear. We combined single-molecule imaging and biochemical investigations with the goal of revealing the mechanism by which cellobiose inhibits the activity of Trichoderma reesei Cel7A, a well-characterized exo-cellulase. We find that cellobiose slows the processive velocity of Cel7A and shortens the distance moved per encounter; effects that can be explained by cellobiose binding to the product release site of the enzyme. Cellobiose also strongly inhibits the binding of Cel7A to immobilized cellulose, with a Ki of 2.1 mM. The isolated catalytic domain (CD) of Cel7A was also inhibited to a similar degree by cellobiose, and binding of an isolated carbohydrate-binding module to cellulose was not inhibited by cellobiose, suggesting that cellobiose acts on the CD alone. Finally, cellopentaose inhibited Cel7A binding at micromolar concentrations without affecting the enzyme's velocity of movement along cellulose. Together, these results suggest that cellobiose inhibits Cel7A activity both by binding to the "back door" product release site to slow activity and to the "front door" substrate-binding tunnel to inhibit interaction with cellulose. These findings point to strategies for engineering cellulases to reduce product inhibition and enhance cellulose degradation, supporting the growth of a sustainable bioeconomy.
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Affiliation(s)
- Daguan Nong
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Zachary K. Haviland
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
| | - Nerya Zexer
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - Sarah A. Pfaff
- Department of Biology, Pennsylvania State University, University Park, PA16802
- Intercollege Graduate Degree Program in Plant Biology, Department of Biology, The Pennsylvania State University, University Park, PA16802
| | - Daniel J. Cosgrove
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - Ming Tien
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA16802
| | - Charles T. Anderson
- Department of Biology, Pennsylvania State University, University Park, PA16802
| | - William O. Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, PA16802
- Department of Chemistry, Pennsylvania State University, University Park, PA16802
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Dadwal A, Singh V, Sharma S, Sahoo AK, Satyanarayana T. Structural and thermostability insights into cellobiohydrolase of a thermophilic mould Myceliophthora thermophila: in-silico studies. J Biomol Struct Dyn 2023; 41:8373-8382. [PMID: 36238990 DOI: 10.1080/07391102.2022.2133012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 10/02/2022] [Indexed: 10/17/2022]
Abstract
Cellobiohydrolase (CBH) is one of the cellulases with a wide range of industrial applications; it plays a pivotal role in cellulose hydrolysis and thus in biofuel production. The structural and thermostability analysis of a CBHII of the thermophilic mold Myceliophthora thermophila (MtCel6A) had been carried out using various in-silico approaches. The validation of 3 D model by the Ramachandran plot indicated 88.5% amino acid residues in the favoured regions. Docking analysis suggested MtCel6A to display a high affinity towards cellotetraose as compared to other substrates. The enzyme exhibited a high tolerance to the end product, cellobiose. The thermostability evaluation by molecular dynamic simulations and principal component analysis confirmed its tolerance to elevated temperatures. The identified thermolabile regions could be targeted for site-directed mutagenesis in order to ameliorate thermostability further. Our experimental data published earlier confirmed the present findings of in-silico studies. The structural and functional characteristics of MtCel6A highlighted its critical features that make it a useful biocatalyst in several industrial processes.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Anica Dadwal
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology, Dwarka, New Delhi, India
- Department of Applied Sciences and Humanities (Faculty of Technology), University of Delhi, Delhi, India
| | - Vishal Singh
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Allahabad, Uttar Pradesh, India
| | - Shilpa Sharma
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology, Dwarka, New Delhi, India
- Department of Applied Sciences and Humanities (Faculty of Technology), University of Delhi, Delhi, India
| | - Amaresh Kumar Sahoo
- Department of Applied Sciences, Indian Institute of Information Technology Allahabad, Allahabad, Uttar Pradesh, India
| | - Tulasi Satyanarayana
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology, Dwarka, New Delhi, India
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5
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Khamassi A, Dumon C. Enzyme synergy for plant cell wall polysaccharide degradation. Essays Biochem 2023; 67:521-531. [PMID: 37067158 DOI: 10.1042/ebc20220166] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/17/2023] [Accepted: 03/07/2023] [Indexed: 04/18/2023]
Abstract
Valorizing plant cell wall, marine and algal polysaccharides is of utmost importance for the development of the circular bioeconomy. This is because polysaccharides are by far the most abundant organic molecules found in nature with complex chemical structures that require a large set of enzymes for their degradation. Microorganisms produce polysaccharide-specific enzymes that act in synergy when performing hydrolysis. Although discovered since decades enzyme synergy is still poorly understood at the molecular level and thus it is difficult to harness and optimize. In the last few years, more attention has been given to improve and characterize enzyme synergy for polysaccharide valorization. In this review, we summarize literature to provide an overview of the different type of synergy involving carbohydrate modifying enzymes and the recent advances in the field exemplified by plant cell-wall degradation.
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Affiliation(s)
- Ahmed Khamassi
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
- Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Claire Dumon
- TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France
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6
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The interplay between lytic polysaccharide monooxygenases and glycoside hydrolases. Essays Biochem 2023; 67:551-559. [PMID: 36876880 DOI: 10.1042/ebc20220156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/23/2022] [Accepted: 01/03/2023] [Indexed: 03/07/2023]
Abstract
In nature, enzymatic degradation of recalcitrant polysaccharides such as chitin and cellulose takes place by a synergistic interaction between glycoside hydrolases (GHs) and lytic polysaccharide monooxygenases (LPMOs). The two different families of carbohydrate-active enzymes use two different mechanisms when breaking glycosidic bonds between sugar moieties. GHs employ a hydrolytic activity and LPMOs are oxidative. Consequently, the topologies of the active sites differ dramatically. GHs have tunnels or clefts lined with a sheet of aromatic amino acid residues accommodating single polymer chains being threaded into the active site. LPMOs are adapted to bind to the flat crystalline surfaces of chitin and cellulose. It is believed that the LPMO oxidative mechanism provides new chain ends that the GHs can attach to and degrade, often in a processive manner. Indeed, there are many reports of synergies as well as rate enhancements when LPMOs are applied in concert with GHs. Still, these enhancements vary in magnitude with respect to the nature of the GH and the LPMO. Moreover, impediment of GH catalysis is also observed. In the present review, we discuss central works where the interplay between LPMOs and GHs has been studied and comment on future challenges to be addressed to fully use the potential of this interplay to improve enzymatic polysaccharide degradation.
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Noguchi T, Nishiyama R, Shimokawa T, Yamada K, Kagawa Y. Simultaneous production of cellobiose and xylobiose from alkali-treated bagasse using cellulase secreted by Fe-ion-irradiated Trichoderma reesei mutant. J Biosci Bioeng 2022; 134:491-495. [PMID: 36220721 DOI: 10.1016/j.jbiosc.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/05/2022]
Abstract
Cellobiose and xylobiose are disaccharides composed of two glucose or xylose units with β-1,4 linkages. This study aimed to isolate a Trichoderma reesei mutant that lacks β-glucosidase and β-xylosidase activities for the simultaneous production of these disaccharides. Mutagenesis using Fe-ion beam resulted in a mutant strain, T. reesei T1640; the cellulase production in this strain was as high as that in the parent strain. Genomic analysis revealed that T1640 lost both the β-glucosidase and β-xylosidase activities owing to the translocation of the responsible genes. Hydrolysis of alkali-treated bagasse using the enzymes from T1640 leads to high yields (365 mg/g-biomass) and ratios (72.7% of the total sugars) of cellobiose and xylobiose.
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Affiliation(s)
- Takuya Noguchi
- New Frontiers Research Laboratory, Toray Industries, Inc., 6-10-1 Tebiro, Kamakura, Kanagawa 248-8555, Japan
| | - Ryuji Nishiyama
- New Frontiers Research Laboratory, Toray Industries, Inc., 6-10-1 Tebiro, Kamakura, Kanagawa 248-8555, Japan
| | - Takashi Shimokawa
- National Institutes of Quantum Science and Technology (QST), 4-9-1 Anagawa, Inage, Chiba 263-8555, Japan
| | - Katsushige Yamada
- New Frontiers Research Laboratory, Toray Industries, Inc., 6-10-1 Tebiro, Kamakura, Kanagawa 248-8555, Japan
| | - Yusuke Kagawa
- New Frontiers Research Laboratory, Toray Industries, Inc., 6-10-1 Tebiro, Kamakura, Kanagawa 248-8555, Japan.
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Biochemical characterization of the β-glucosidase Glu1B from Coptotermes formosanus produced in Pichia pastoris. Enzyme Microb Technol 2022; 163:110155. [DOI: 10.1016/j.enzmictec.2022.110155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 10/22/2022] [Accepted: 11/08/2022] [Indexed: 11/13/2022]
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Pant S, Ritika, Nag P, Ghati A, Chakraborty D, Maximiano MR, Franco OL, Mandal AK, Kuila A. Employment of the CRISPR/Cas9 system to improve cellulase production in Trichoderma reesei. Biotechnol Adv 2022; 60:108022. [PMID: 35870723 DOI: 10.1016/j.biotechadv.2022.108022] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 07/05/2022] [Accepted: 07/17/2022] [Indexed: 12/27/2022]
Abstract
Trichoderma reesei has been explored intensively in the laboratory and on an industrial scale for its highly potent cellulase secretion machinery since its characterization over 70 years ago. Emergence of new genetic tools over the past decade has strengthened the understanding of mechanism involved in transcription of cellulase genes in fungi and provided a boost to edit them at molecular level. Since several transcriptional factors work synergistically for cellulase expression in fungi; engineering of cellulase secretome for enhanced cellulase titer require combined manipulation of these factors. In the same context, CRISPR/Cas9 has emerged as a powerful, versatile genetic engineering tool for multiplex gene editing in fungi. It is true that considerable efforts with CRISPR technologies have largely developed fungal genetic engineering, but its application in fungi is still challenging and limited. The present review illustrates the precision, strengths and challenges of using CRISPR/Cas9 technology for cellulase engineering in T. reesei, highlighting key strategies that could be employed for strain improvement.
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Affiliation(s)
- Shailja Pant
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India
| | - Ritika
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India
| | - Piyali Nag
- Department of Microbiology, Barrackpore Rastraguru Surendranath College, Barrackpore, Kolkata 700120, India
| | - Amit Ghati
- Department of Microbiology, Barrackpore Rastraguru Surendranath College, Barrackpore, Kolkata 700120, India.
| | - Dipjyoti Chakraborty
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India
| | - Mariana Rocha Maximiano
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia Universidade Católica de Brasília, Brasília, DF, Brazil; S-Inova Biotech, Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Octavio Luiz Franco
- Centro de Análises Proteômicas e Bioquímicas, Pós-Graduação em Ciências Genômicas e Biotecnologia Universidade Católica de Brasília, Brasília, DF, Brazil; S-Inova Biotech, Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande, MS, Brazil
| | - Amit Kumar Mandal
- Centre for Nanotechnology Sciences & Chemical Biology Laboratory, Department of Sericulture, Raiganj University, Raiganj, 733134, India
| | - Arindam Kuila
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Rajasthan 304022, India.
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Metagenomic mining and structure-function studies of a hyper-thermostable cellobiohydrolase from hot spring sediment. Commun Biol 2022; 5:247. [PMID: 35318423 PMCID: PMC8940973 DOI: 10.1038/s42003-022-03195-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/25/2022] [Indexed: 11/09/2022] Open
Abstract
Enzymatic breakdown is an attractive cellulose utilisation method with a low environmental load. Its high temperature operation could promote saccharification and lower contamination risk. Here we report a hyper-thermostable cellobiohydrolase (CBH), named HmCel6A and its variant HmCel6A-3SNP that were isolated metagenomically from hot spring sediments and expressed in Escherichia coli. They are classified into glycoside hydrolases family 6 (GH6). HmCel6A-3SNP had three amino acid replacements to HmCel6A (P88S/L230F/F414S) and the optimum temperature at 95 °C, while HmCel6A did it at 75 °C. Crystal structure showed conserved features among GH6, a (β/α)8-barrel core and catalytic residues, and resembles TfCel6B, a bacterial CBH II of Thermobifida fusca, that had optimum temperature at 60 °C. From structure-function studies, we discuss unique structural features that allow the enzyme to reach its high thermostability level, such as abundance of hydrophobic and charge-charge interactions, characteristic metal bindings and disulphide bonds. Moreover, structure and surface plasmon resonance analysis with oligosaccharides suggested that the contribution of an additional tryptophan located at the tunnel entrance could aid in substrate recognition and thermostability. These results may help to design efficient enzymes and saccharification methods for cellulose working at high temperatures. Bacteria from hot springs are known for highly thermostable enzymes, which may have industrial potential. Here, a unique thermostable cellobiohydrolase is reported that can breakdown cellulose at temperature up to 95 degrees Celsius.
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Iram A, Cekmecelioglu D, Demirci A. Salt and nitrogen amendment and optimization for cellulase and xylanase production using dilute acid hydrolysate of distillers' dried grains with solubles (DDGS) as the feedstock. Bioprocess Biosyst Eng 2022; 45:527-540. [PMID: 35013794 DOI: 10.1007/s00449-021-02676-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022]
Abstract
Distillers' dried grains with solubles (DDGS) is a by-product of dry-mill corn ethanol production comprising a high nutritional value due to residual fiber, protein, and lipid contents. The fiber content of DDGS is high enough to be considered a valuable source for the production of hydrolytic enzymes, such as cellulase and xylanases, which can be used for hydrolysis of lignocellulosic feedstock during ethanol production. The DDGS-based medium prepared after acid hydrolysis provides adequate sugars for enzyme production, while additional macronutrients, such as salts and nitrogen sources, can enhance the enzyme production. Therefore, this study was undertaken to evaluate the effect of salts (KH2PO4, CaCl2·2H2O, MgSO4·7H2O, FeSO4·7H2O, CoCl2·6H2O, and MnSO4·H2O), peptone, and yeast extract on enzyme secretion by four different Aspergillus niger strains and to optimize the nitrogen source for maximum enzyme production. Yeast extract improved the cellulase production (0.38 IU/ml) for A. niger (NRRL 1956) as compared to peptone (0.29 IU/ml). However, maximum cellulase productions of 0.42 IU/ml and 0.45 IU/ml were obtained by A. niger (NRRL 330) and A. niger (NRRL 567), respectively, in presence of ammonium sulfate. The optimized nitrogen amounts resulted in a significant increase in the cellulase production from 0.174 to 0.63 IU/ml on day 9 of the fermentation with A. niger (NRRL 330). The composite model improved both cellulase and xylanase production. In conclusion, the optimization of all three nitrogen sources improved both cellulase and xylanase production in the DDGS-based media.
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Affiliation(s)
- Attia Iram
- Department of Agricultural and Biological Engineering, Pennsylvania State University, 221 Agricultural Engineering Building, University Park, PA, 16802, USA
| | - Deniz Cekmecelioglu
- Department of Food Engineering, Middle East Technical University, 06800, Ankara, Turkey
| | - Ali Demirci
- Department of Agricultural and Biological Engineering, Pennsylvania State University, 221 Agricultural Engineering Building, University Park, PA, 16802, USA.
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Abstract
Abstract
The serious issue of textile waste accumulation has raised attention on biodegradability as a possible route to support sustainable consumption of textile fibers. However, synthetic textile fibers that dominate the market, especially poly(ethylene terephthalate) (PET), resist biological degradation, creating environmental and waste management challenges. Because pure natural fibers, like cotton, both perform well for consumer textiles and generally meet certain standardized biodegradability criteria, inspiration from the mechanisms involved in natural biodegradability are leading to new discoveries and developments in biologically accelerated textile waste remediation for both natural and synthetic fibers. The objective of this review is to present a multidisciplinary perspective on the essential bio-chemo-physical requirements for textile materials to undergo biodegradation, taking into consideration the impact of environmental or waste management process conditions on biodegradability outcomes. Strategies and recent progress in enhancing synthetic textile fiber biodegradability are reviewed, with emphasis on performance and biodegradability behavior of poly(lactic acid) (PLA) as an alternative biobased, biodegradable apparel textile fiber, and on biological strategies for addressing PET waste, including industrial enzymatic hydrolysis to generate recyclable monomers. Notably, while pure PET fibers do not biodegrade within the timeline of any standardized conditions, recent developments with process intensification and engineered enzymes show that higher enzymatic recycling efficiency for PET polymer has been achieved compared to cellulosic materials. Furthermore, combined with alternative waste management practices, such as composting, anaerobic digestion and biocatalyzed industrial reprocessing, the development of synthetic/natural fiber blends and other strategies are creating opportunities for new biodegradable and recyclable textile fibers.
Article Highlights
Poly(lactic acid) (PLA) leads other synthetic textile fibers in meeting both performance and biodegradation criteria.
Recent research with poly(ethylene terephthalate) (PET) polymer shows potential for efficient enzyme catalyzed industrial recycling.
Synthetic/natural fiber blends and other strategies could open opportunities for new biodegradable and recyclable textile fibers.
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13
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Tareen A, Punsuvon V, Sultan IN, Khan MW, Parakulsuksatid P. Cellulase Addition and Pre-hydrolysis Effect of High Solid Fed-Batch Simultaneous Saccharification and Ethanol Fermentation from a Combined Pretreated Oil Palm Trunk. ACS OMEGA 2021; 6:26119-26129. [PMID: 34660972 PMCID: PMC8515579 DOI: 10.1021/acsomega.1c03111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 09/16/2021] [Indexed: 06/13/2023]
Abstract
In the current study, alkaline hydrogen peroxide pretreated oil palm trunk fibers were subjected to ethanol production via simultaneous saccharification and fermentation (SSF). The effect of high substrate loading, enzyme and substrate feeding strategy, and influence of a pre-hydrolysis step in SSF was studied to scale up ethanol production. In the enzyme feeding strategy, the addition of an enzyme at the start of fed-batch SSF significantly (p < 0.05) increased ethanol concentration to 51.05 g/L, ethanol productivity (QP ) to 0.61 g/L·h, and ethanol yield (Y P/S) to 0.31 g/g, with a theoretical ethanol yield of 60.65%. Furthermore, the initial velocity of the enzyme (V 0) in the first 8 h was 2.27 (g/h) with a glucose concentration of 18.17 g/L. On the other hand, the substrate feeding strategy and pre-hydrolysis simultaneous saccharification and fermentation (PSSF) process were studied in a 1 L fermenter. PSSF in fed batch with 10 and 20% (w/v) significantly improved enzyme hydrolysis, circumvent the problems of high viscosity, reduced overall fermentation time, and gave the highest ethanol concentration of 51.66 g/L, ethanol productivity (QP ) of 0.72 g/L·h, ethanol yield (Y P/S) of 0.31 g/g, and theoretical ethanol yield of 60.66%. In addition, PSSF with 10 and 20% significantly increased the initial velocity of the enzyme (V 0) to 4.64 and 4.40 (g/h) and glucose concentration to 37.14 and 35.27 g/L, respectively. This result indicated that ethanol production by PSSF along with substrate feeding could enhance ethanol production efficiently.
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Affiliation(s)
- Afrasiab
Khan Tareen
- Department
of Biotechnology, Faculty of Agro-Industry, Kasetsart University, 50 Ngam Wong Wan Rd, Ladyao, Chatuchak, Bangkok 10900, Thailand
| | - Vittaya Punsuvon
- Department
of Chemistry, Faculty of Science, Kasetsart
University, 50 Ngam Wong Wan Rd, Ladyao, Chatuchak, Bangkok 10900, Thailand
| | - Imrana Niaz Sultan
- Department
of Biotechnology, Faculty of Life Sciences and Informatics, BUITEMS, Quetta 87300, Pakistan
| | - Muhammad Waseem Khan
- Department
of Biotechnology, Faculty of Life Sciences and Informatics, BUITEMS, Quetta 87300, Pakistan
| | - Pramuk Parakulsuksatid
- Department
of Biotechnology, Faculty of Agro-Industry, Kasetsart University, 50 Ngam Wong Wan Rd, Ladyao, Chatuchak, Bangkok 10900, Thailand
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14
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Zou G, Bao D, Wang Y, Zhou S, Xiao M, Yang Z, Wang Y, Zhou Z. Alleviating product inhibition of Trichoderma reesei cellulase complex with a product-activated mushroom endoglucanase. BIORESOURCE TECHNOLOGY 2021; 319:124119. [PMID: 32957048 DOI: 10.1016/j.biortech.2020.124119] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 06/11/2023]
Abstract
Product inhibition of cellulase is a challenging issue in industrial processes. Here, we introduced a product-activated mushroom cellulase, PaCel3A from Polyporus arcularius, into Trichoderma reesei. The filter paper activity, carboxymethyl cellulase activity, and saccharification efficiency (substrate: pretreated rice straw, PRS) of transformants increased significantly with this enzyme (by 18.4-26.8%, 13.8-22.8%, and 17.0%, respectively). A mutant of PaCel3A, PaCel3AM, obtained based on B-factor analysis, saturated mutagenesis, and residual activity assay, showed improved thermostability. The PRS saccharification efficiency using the cellulase complex from T. reesei transformants overexpressing pacel3am increased by 56.4%-63.0%. In addition, the T. reesei cellulase complex obtained by adding the purified recombinant PaCel3AM from T. reesei (rCel3aM-tr) to hydrolyze PRS resulted in increased reducing sugar yields at all sampling points, outperforming the cellulase complexes without rCel3aM-tr. These results suggest that introducing product-activated cellulase genes is a simple and feasible method to alleviate the product inhibition of cellulase.
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Affiliation(s)
- Gen Zou
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China; CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Dapeng Bao
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China.
| | - Ying Wang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Sichi Zhou
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Meili Xiao
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Zhanshan Yang
- Shanghai Key Laboratory of Agricultural Genetics and Breeding; Institute of Edible Fungi, Shanghai Academy of Agriculture Science, 1000 Jinqi Rd, Fengxian 201403, Shanghai, China
| | - Yinmei Wang
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
| | - Zhihua Zhou
- CAS-Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Science, Fenglin Rd 300, Shanghai 200032, China.
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Bernardi AV, Gerolamo LE, de Gouvêa PF, Yonamine DK, Pereira LMS, de Oliveira AHC, Uyemura SA, Dinamarco TM. LPMO AfAA9_B and Cellobiohydrolase AfCel6A from A. fumigatus Boost Enzymatic Saccharification Activity of Cellulase Cocktail. Int J Mol Sci 2020; 22:E276. [PMID: 33383972 PMCID: PMC7795096 DOI: 10.3390/ijms22010276] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/21/2020] [Accepted: 12/24/2020] [Indexed: 01/02/2023] Open
Abstract
Cellulose is the most abundant polysaccharide in lignocellulosic biomass, where it is interlinked with lignin and hemicellulose. Bioethanol can be produced from biomass. Since breaking down biomass is difficult, cellulose-active enzymes secreted by filamentous fungi play an important role in degrading recalcitrant lignocellulosic biomass. We characterized a cellobiohydrolase (AfCel6A) and lytic polysaccharide monooxygenase LPMO (AfAA9_B) from Aspergillus fumigatus after they were expressed in Pichia pastoris and purified. The biochemical parameters suggested that the enzymes were stable; the optimal temperature was ~60 °C. Further characterization revealed high turnover numbers (kcat of 147.9 s-1 and 0.64 s-1, respectively). Surprisingly, when combined, AfCel6A and AfAA9_B did not act synergistically. AfCel6A and AfAA9_B association inhibited AfCel6A activity, an outcome that needs to be further investigated. However, AfCel6A or AfAA9_B addition boosted the enzymatic saccharification activity of a cellulase cocktail and the activity of cellulase Af-EGL7. Enzymatic cocktail supplementation with AfCel6A or AfAA9_B boosted the yield of fermentable sugars from complex substrates, especially sugarcane exploded bagasse, by up to 95%. The synergism between the cellulase cocktail and AfAA9_B was enzyme- and substrate-specific, which suggests a specific enzymatic cocktail for each biomass by up to 95%. The synergism between the cellulase cocktail and AfAA9_B was enzyme- and substrate-specific, which suggests a specific enzymatic cocktail for each biomass.
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Affiliation(s)
- Aline Vianna Bernardi
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
| | - Luis Eduardo Gerolamo
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
| | - Paula Fagundes de Gouvêa
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
| | - Deborah Kimie Yonamine
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
| | - Lucas Matheus Soares Pereira
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
| | - Arthur Henrique Cavalcante de Oliveira
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
| | - Sérgio Akira Uyemura
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-903, Brazil;
| | - Taisa Magnani Dinamarco
- Faculdade de Filosofia Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto 14040-901, Brazil; (A.V.B.); (L.E.G.); (P.F.d.G.); (D.K.Y.); (L.M.S.P.); (A.H.C.d.O.)
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16
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Claes A, Deparis Q, Foulquié-Moreno MR, Thevelein JM. Simultaneous secretion of seven lignocellulolytic enzymes by an industrial second-generation yeast strain enables efficient ethanol production from multiple polymeric substrates. Metab Eng 2020; 59:131-141. [DOI: 10.1016/j.ymben.2020.02.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/01/2020] [Accepted: 02/18/2020] [Indexed: 01/22/2023]
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17
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Røjel N, Kari J, Sørensen TH, Borch K, Westh P. pH profiles of cellulases depend on the substrate and architecture of the binding region. Biotechnol Bioeng 2019; 117:382-391. [PMID: 31631319 DOI: 10.1002/bit.27206] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 09/09/2019] [Accepted: 10/13/2019] [Indexed: 01/06/2023]
Abstract
Understanding the pH effect of cellulolytic enzymes is of great technological importance. In this study, we have examined the influence of pH on activity and stability for central cellulases (Cel7A, Cel7B, Cel6A from Trichoderma reesei, and Cel7A from Rasamsonia emersonii). We systematically changed pH from 2 to 7, temperature from 20°C to 70°C, and used both soluble (4-nitrophenyl β- d-lactopyranoside [pNPL]) and insoluble (Avicel) substrates at different concentrations. Collective interpretation of these data provided new insights. An unusual tolerance to acidic conditions was observed for both investigated Cel7As, but only on real insoluble cellulose. In contrast, pH profiles on pNPL were bell-shaped with a strong loss of activity both above and below the optimal pH for all four enzymes. On a practical level, these observations call for the caution of the common practice of using soluble substrates for the general characterization of pH effects on cellulase activity. Kinetic modeling of the experimental data suggested that the nucleophile of Cel7A experiences a strong downward shift in pKa upon complexation with an insoluble substrate. This shift was less pronounced for Cel7B, Cel6A, and for Cel7A acting on the soluble substrate, and we hypothesize that these differences are related to the accessibility of water to the binding region of the Michaelis complex.
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Affiliation(s)
- Nanna Røjel
- Department of Science and Environment (INM), Roskilde University, Roskilde, Denmark.,Present address: Department of Biotechnology and Biomedicine, Technical University of Denmark, Building 224, DK-2800, Kgs. Lyngby, Denmark
| | - Jeppe Kari
- Department of Science and Environment (INM), Roskilde University, Roskilde, Denmark.,Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | | | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
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18
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Kari J, Christensen SJ, Andersen M, Baiget SS, Borch K, Westh P. A practical approach to steady-state kinetic analysis of cellulases acting on their natural insoluble substrate. Anal Biochem 2019; 586:113411. [PMID: 31520594 DOI: 10.1016/j.ab.2019.113411] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/26/2019] [Accepted: 08/28/2019] [Indexed: 10/26/2022]
Abstract
Measurement of steady-state rates (vSS) is straightforward in standard enzymology with soluble substrate, and it has been instrumental for comparative biochemical analyses within this area. For insoluble substrate, however, experimental values of vss remain controversial, and this has strongly limited the amount and quality of comparative analyses for cellulases and other enzymes that act on the surface of an insoluble substrate. In the current work, we have measured progress curves over a wide range of conditions for two cellulases, TrCel6A and TrCel7A from Trichoderma reesei, acting on their natural, insoluble substrate, cellulose. Based on this, we consider practical compromises for the determination of experimental vSS values, and propose a basic protocol that provides representative reaction rates and is experimentally simple so that larger groups of enzymes and conditions can be readily assayed with standard laboratory equipment. We surmise that the suggested experimental approach can be useful in comparative biochemical studies of cellulases; an area that remains poorly developed.
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Affiliation(s)
- Jeppe Kari
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark
| | - Stefan Jarl Christensen
- Department of Science and Environment, Roskilde University, Universitetsvej, Build. 28.C, DK-4000, Roskilde, Denmark
| | - Morten Andersen
- Department of Science and Environment, Roskilde University, Universitetsvej, Build. 28.C, DK-4000, Roskilde, Denmark
| | | | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 224, DK-2800, Kgs. Lyngby, Denmark.
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19
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Wang Y, Leng L, Islam MK, Liu F, Lin CSK, Leu SY. Substrate-Related Factors Affecting Cellulosome-Induced Hydrolysis for Lignocellulose Valorization. Int J Mol Sci 2019; 20:ijms20133354. [PMID: 31288425 PMCID: PMC6651384 DOI: 10.3390/ijms20133354] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 06/30/2019] [Accepted: 07/03/2019] [Indexed: 11/22/2022] Open
Abstract
Cellulosomes are an extracellular supramolecular multienzyme complex that can efficiently degrade cellulose and hemicelluloses in plant cell walls. The structural and unique subunit arrangement of cellulosomes can promote its adhesion to the insoluble substrates, thus providing individual microbial cells with a direct competence in the utilization of cellulosic biomass. Significant progress has been achieved in revealing the structures and functions of cellulosomes, but a knowledge gap still exists in understanding the interaction between cellulosome and lignocellulosic substrate for those derived from biorefinery pretreatment of agricultural crops. The cellulosomic saccharification of lignocellulose is affected by various substrate-related physical and chemical factors, including native (untreated) wood lignin content, the extent of lignin and xylan removal by pretreatment, lignin structure, substrate size, and of course substrate pore surface area or substrate accessibility to cellulose. Herein, we summarize the cellulosome structure, substrate-related factors, and regulatory mechanisms in the host cells. We discuss the latest advances in specific strategies of cellulosome-induced hydrolysis, which can function in the reaction kinetics and the overall progress of biorefineries based on lignocellulosic feedstocks.
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Affiliation(s)
- Ying Wang
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Ling Leng
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Md Khairul Islam
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Fanghua Liu
- Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Guangdong Institute of Eco-Environmental Science & Technology, Guangzhou 510650, China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China
| | - Shao-Yuan Leu
- Department of Civil and Environmental Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
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20
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Wang Z, Dien BS, Rausch KD, Tumbleson ME, Singh V. Improving ethanol yields with deacetylated and two-stage pretreated corn stover and sugarcane bagasse by blending commercial xylose-fermenting and wild type Saccharomyces yeast. BIORESOURCE TECHNOLOGY 2019; 282:103-109. [PMID: 30852329 DOI: 10.1016/j.biortech.2019.02.123] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/27/2019] [Accepted: 02/28/2019] [Indexed: 06/09/2023]
Abstract
Corn stover and sugarcane bagasse are the most widely available agriculture processing biomass and could serve as feedstocks for production of biofuel. In this study, three different technologies are combined to develop a more efficient conversion process for each of these feedstocks. The three technologies are diluted alkaline deacetylation process, combined thermochemical and mechanical shear pretreatment, and fermentation using a combined inoculum of two commercial Saccharomyces yeast strains. The two yeast strains used were a non-GMO and GMO strain engineered for xylose fermentation. The final ethanol concentrations obtained were 35.7 g/L from deacetylated corn stover and 32.9 g/L from sugarcane bagasse. Blending the two yeast reduced residual xylose content from 1.24 g/L to 0.48 g/L and increased ethanol production by 6.5% compared to solely using the C5/C6 yeast. The optimized yeast blend also lowered the amount of C5/C6 yeast required for inoculation by 80%.
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Affiliation(s)
- Zhaoqin Wang
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Bruce S Dien
- National Center for Agricultural Utilization Research, USDA, Peoria, IL, USA
| | - Kent D Rausch
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - M E Tumbleson
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Vijay Singh
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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21
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Siqueira GA, Dias IKR, Arantes V. Exploring the action of endoglucanases on bleached eucalyptus kraft pulp as potential catalyst for isolation of cellulose nanocrystals. Int J Biol Macromol 2019; 133:1249-1259. [PMID: 31047930 DOI: 10.1016/j.ijbiomac.2019.04.162] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 04/22/2019] [Accepted: 04/22/2019] [Indexed: 10/26/2022]
Abstract
Cellulose nanocrystals (CNCs) is a high-value and emerging bionanomaterial with an increasing number of applications. The action of endoglucanases (EGs) from fungal and bacterial sources belonging to three glycosyl hydrolase (GH) families were investigated on bleached eucalyptus kraft pulp as potential catalysts to prepare CNC. Fungal GH7EG was the most efficient in hydrolysis and fiber fragmentation without altering crystallinity and crystallite size. Fiber fragmentation promoted by fungal GH45EG was similar to that observed for GH7EG, although it released a smaller amount of sugar. Bacterial GH5EG resulted in very low hydrolysis yield and practically did not fragment the fibers, resulting in a hydrolysis residue with characteristics very similar to the initial material. GH45EG was the only EG that affected the crystallinity and crystallite size and also the only enzyme capable of isolating nanoparticles. The isolated nanoparticles had very narrow width distribution range of 6-10 nm and length distribution range of 400-600 nm. Supplementation of β-glucosidase and conventional mechanical refining as a pretreatment did not improve the release of nanoparticles. Despite catalyzing the same biochemical reaction, different EGs displayed very distinct action during hydrolysis. The reported strong binding of GH45EG's CBM to the cellulose and the lack of increased accessibility of the enzyme to new substrate likely allowed continuous hydrolysis of the few fibers available, resulting in the isolation of cellulose nanoparticles.
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Affiliation(s)
- Germano A Siqueira
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
| | - Isabella K R Dias
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
| | - Valdeir Arantes
- Biocatalysis and Bioproducts Laboratory, Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil.
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22
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Heterologous co-expression of two β-glucanases and a cellobiose phosphorylase resulted in a significant increase in the cellulolytic activity of the Caldicellulosiruptor bescii exoproteome. J Ind Microbiol Biotechnol 2019; 46:687-695. [PMID: 30783893 DOI: 10.1007/s10295-019-02150-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 02/12/2019] [Indexed: 12/20/2022]
Abstract
The ability to deconstruct plant biomass without conventional pretreatment has made members of the genus Caldicellulosiruptor the target of investigation for the consolidated processing of plant lignocellulosic biomass to biofuels and bioproducts. To investigate the synergy of enzymes involved and to further improve the ability of C. bescii to degrade cellulose, we introduced CAZymes that act synergistically with the C. bescii exoproteome in vivo and in vitro. We recently demonstrated that the Acidothermus cellulolyticus E1 endo-1,4-β-D-glucanase (GH5) with a family 2 carbohydrate-binding module (CBM) increased the activity of C. bescii exoproteome on biomass, presumably acting in concert with CelA. The β-glucanase, GuxA, from A. cellulolyticus is a multi-domain enzyme with strong processive exoglucanase activity, and the cellobiose phosphorylase from Thermotoga maritima catalyzes cellulose degradation acting synergistically with cellobiohydrolases and endoglucanases. We identified new chromosomal insertion sites to co-express these enzymes and the resulting strain showed a significant increase in the enzymatic activity of the exoproteome.
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23
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Müller MJ, Stachurski S, Stoffels P, Schipper K, Feldbrügge M, Büchs J. Online evaluation of the metabolic activity of Ustilago maydis on (poly)galacturonic acid. J Biol Eng 2018; 12:34. [PMID: 30574186 PMCID: PMC6299674 DOI: 10.1186/s13036-018-0128-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/03/2018] [Indexed: 11/10/2022] Open
Abstract
Background Pectin is a rather complex and highly branched polysaccharide strengthening the plant cell wall. Thus, many different pectinases are required for an efficient microbial conversion of biomass waste streams with a high pectin content like citrus peel, apple pomace or sugar beet pulp. The screening and optimization of strains growing on pectic substrates requires both, quantification of the residual substrate and an accurate determination of the enzymatic activity. Galacturonic acid, the main sugar unit of pectin, is an uncommon substrate for microbial fermentations. Thus, growth and enzyme production of the applied strain has to be characterized in detail to understand the microbial system. An essential step to reach this goal is the development of online monitoring tools. Results In this study, a method for the online determination of residual substrate was developed for the growth of the plant pathogenic fungus Ustilago maydis on pectic substrates such as galacturonic acid. To this end, an U. maydis strain was used that expressed a heterologous exo-polygalacturonase for growth on polygalacturonic acid. The growth behavior on galacturonic acid was analyzed by online measurement of the respiration activity. A method for the online prediction of the residual galacturonic acid concentration during the cultivation, based on the overall oxygen consumption, was developed and verified by offline sampling. This sensitive method was extended towards polygalacturonic acid, which is challenging to quantify via offline measurements. Finally, the enzymatic activity in the culture supernatant was calculated and the enzyme stability during the course of the cultivation was confirmed. Conclusion The introduced method can reliably predict the residual (poly)galacturonic acid concentration based on the overall oxygen consumption. Based on this method, the enzymatic activity of the culture broth of an U. maydis strain expressing a heterologous exo-polygalacturonase could be calculated. It was demonstrated that the method is especially advantageous for determination of low enzymatic activities. In future, it will be applied to U. maydis strains in which the number of produced hydrolytic enzymes is increased for more efficient degradation. Electronic supplementary material The online version of this article (10.1186/s13036-018-0128-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Markus Jan Müller
- 1AVT - Biochemical Engineering, RWTH Aachen University, Jochen Büchs, Forckenbeckstr. 51, 52074 Aachen, Germany.,Bioeconomy Science Center (BioSC), 52426 Jülich, Germany
| | - Sarah Stachurski
- 1AVT - Biochemical Engineering, RWTH Aachen University, Jochen Büchs, Forckenbeckstr. 51, 52074 Aachen, Germany
| | - Peter Stoffels
- 2Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.,Bioeconomy Science Center (BioSC), 52426 Jülich, Germany
| | - Kerstin Schipper
- 2Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.,Bioeconomy Science Center (BioSC), 52426 Jülich, Germany
| | - Michael Feldbrügge
- 2Institute for Microbiology, Cluster of Excellence on Plant Sciences, Heinrich-Heine University Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.,Bioeconomy Science Center (BioSC), 52426 Jülich, Germany
| | - Jochen Büchs
- 1AVT - Biochemical Engineering, RWTH Aachen University, Jochen Büchs, Forckenbeckstr. 51, 52074 Aachen, Germany.,Bioeconomy Science Center (BioSC), 52426 Jülich, Germany
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24
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Schiano-di-Cola C, Røjel N, Jensen K, Kari J, Sørensen TH, Borch K, Westh P. Systematic deletions in the cellobiohydrolase (CBH) Cel7A from the fungus Trichoderma reesei reveal flexible loops critical for CBH activity. J Biol Chem 2018; 294:1807-1815. [PMID: 30538133 DOI: 10.1074/jbc.ra118.006699] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/08/2018] [Indexed: 11/06/2022] Open
Abstract
Glycoside hydrolase family 7 (GH7) cellulases are some of the most efficient degraders of cellulose, making them particularly relevant for industries seeking to produce renewable fuels from lignocellulosic biomass. The secretome of the cellulolytic model fungus Trichoderma reesei contains two GH7s, termed TrCel7A and TrCel7B. Despite having high structural and sequence similarities, the two enzymes are functionally quite different. TrCel7A is an exolytic, processive cellobiohydrolase (CBH), with high activity on crystalline cellulose, whereas TrCel7B is an endoglucanase (EG) with a preference for more amorphous cellulose. At the structural level, these functional differences are usually ascribed to the flexible loops that cover the substrate-binding areas. TrCel7A has an extensive tunnel created by eight peripheral loops, and the absence of four of these loops in TrCel7B makes its catalytic domain a more open cleft. To investigate the structure-function relationships of these loops, here we produced and kinetically characterized several variants in which four loops unique to TrCel7A were individually deleted to resemble the arrangement in the TrCel7B structure. Analysis of a range of kinetic parameters consistently indicated that the B2 loop, covering the substrate-binding subsites -3 and -4 in TrCel7A, was a key determinant for the difference in CBH- or EG-like behavior between TrCel7A and TrCel7B. Conversely, the B3 and B4 loops, located closer to the catalytic site in TrCel7A, were less important for these activities. We surmise that these results could be useful both in further mechanistic investigations and for guiding engineering efforts of this industrially important enzyme family.
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Affiliation(s)
- Corinna Schiano-di-Cola
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Nanna Røjel
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark, and
| | - Jeppe Kari
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Trine Holst Sørensen
- From the Department of Science and Environment, Roskilde University, Universitetsvej 1, Building 28, DK-4000 Roskilde, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark, and
| | - Peter Westh
- the Department of Biotechnology and Biomedicine, Technical University of Denmark, Building 224, DK-2800 Kgs. Lyngby, Denmark
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25
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Cellobiose fermentation by Saccharomyces cerevisiae: Comparative analysis of intra versus extracellular sugar hydrolysis. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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26
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He B, Zhu X, Zhao C, Ma Y, Yang W. Sequential co-immobilization of β-glucosidase and yeast cells on single polymer support for bioethanol production. Sci China Chem 2018. [DOI: 10.1007/s11426-018-9319-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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27
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Wang Z, Dien BS, Rausch KD, Tumbleson ME, Singh V. Fermentation of undetoxified sugarcane bagasse hydrolyzates using a two stage hydrothermal and mechanical refining pretreatment. BIORESOURCE TECHNOLOGY 2018; 261:313-321. [PMID: 29677659 DOI: 10.1016/j.biortech.2018.04.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/02/2018] [Accepted: 04/04/2018] [Indexed: 06/08/2023]
Abstract
In this study, liquid hot water pretreatment was combined with disk milling for pretreatment of sugarcane bagasse. Sugarcane bagasse was pretreated using liquid hot water (LHW) at 140-180 °C for 10 min (20% w/w solids content) and then disk milled. Disk milling improved glucose release 41-177% and ethanol production from glucose/xylose cofermentation by 80% compared to only using LHW pretreatment. The highest ethanol conversion efficiency achieved was 94%, which was observed when bagasse was treated at 180 °C with LHW and disk milled. However, a small amount of residual xylose (3 g/L) was indicative that further improvement could be achieved to increase ethanol production.
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Affiliation(s)
- Zhaoqin Wang
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Bruce S Dien
- National Center for Agricultural Utilization Research, US Department of Agriculture, Peoria, IL, USA
| | - Kent D Rausch
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - M E Tumbleson
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Vijay Singh
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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28
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Refactoring the upper sugar metabolism of Pseudomonas putida for co-utilization of cellobiose, xylose, and glucose. Metab Eng 2018; 48:94-108. [DOI: 10.1016/j.ymben.2018.05.019] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/15/2018] [Accepted: 05/31/2018] [Indexed: 01/02/2023]
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29
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Rabinovich ML, Melnik MS, Herner ML, Voznyi YV, Vasilchenko LG. Predominant Nonproductive Substrate Binding by Fungal Cellobiohydrolase I and Implications for Activity Improvement. Biotechnol J 2018; 14:e1700712. [PMID: 29781240 DOI: 10.1002/biot.201700712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 05/08/2018] [Indexed: 12/20/2022]
Abstract
Enzymatic conversion of the most abundant renewable source of organic compounds, cellulose to fermentable sugars is attractive for production of green fuels and chemicals. The major component of industrial enzyme systems, cellobiohydrolase I from Hypocrea jecorina (Trichoderma reesei) (HjCel7A) processively splits disaccharide units from the reducing ends of tightly packed cellulose chains. HjCel7A consists of a catalytic domain (CD) and a carbohydrate-binding module (CBM) separated by a linker peptide. A tunnel-shaped substrate-binding site in the CD includes nine subsites for β-d-glucose units, seven of which (-7 to -1) precede the catalytic center. Low catalytic activity of Cel7A is the bottleneck and the primary target for improvement. Here it is shown for the first time that, in spite of much lower apparent kcat of HjCel7A at the hydrolysis of β-1,4-glucosidic linkages in the fluorogenic cellotetra- and -pentaose compared to the structurally related endoglucanase I (HjCel7B), the specificity constants (catalytic efficiency) kcat /Km for both enzymes are almost equal in these reactions. The observed activity difference appears from strong nonproductive substrate binding by HjCel7A, particularly significant for MU-β-cellotetraose (MUG4 ). Interaction of substrates with the subsites -6 and -5 proximal to the nonconserved Gln101 residue in HjCel7A decreases Km,ap by >1500 times. HjCel7A can be nonproductively bound onto cellulose surface with Kd ≈2-9 nM via CBM and CD that captures six terminal glucose units of cellulose chain. Decomposition of this nonproductive complex can determine the rate of cellulose conversion. MUG4 is a promising substrate to select active cellobiohydrolase I variants with reduced nonproductive substrate binding.
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Affiliation(s)
- Mikhail L Rabinovich
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Maria S Melnik
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Mikhail L Herner
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
| | - Yakov V Voznyi
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia
| | - Lilia G Vasilchenko
- Bach Institute of Biochemistry, Research Center of Biotechnology of the Russian Academy of Sciences, 33, bld. 2 Leninsky Ave., Moscow 119071, Russia
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30
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Karnaouri A, Topakas E, Matsakas L, Rova U, Christakopoulos P. Fine-Tuned Enzymatic Hydrolysis of Organosolv Pretreated Forest Materials for the Efficient Production of Cellobiose. Front Chem 2018; 6:128. [PMID: 29725590 PMCID: PMC5917092 DOI: 10.3389/fchem.2018.00128] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/04/2018] [Indexed: 11/23/2022] Open
Abstract
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.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Evangelos Topakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.,Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Leonidas Matsakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
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31
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Li T, Zhang C, Yang KL, He J. Unique genetic cassettes in a Thermoanaerobacterium contribute to simultaneous conversion of cellulose and monosugars into butanol. SCIENCE ADVANCES 2018; 4:e1701475. [PMID: 29740597 PMCID: PMC5938282 DOI: 10.1126/sciadv.1701475] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 02/07/2018] [Indexed: 05/25/2023]
Abstract
The demand for cellulosic biofuels is on the rise because of the anticipation for sustainable energy and less greenhouse gas emissions in the future. However, production of cellulosic biofuels, especially cellulosic butanol, has been hampered by the lack of potent microbes that are capable of converting cellulosic biomass into biofuels. We report a wild-type Thermoanaerobacterium thermosaccharolyticum strain TG57, which is capable of using microcrystalline cellulose directly to produce butanol (1.93 g/liter) as the only final product (without any acetone or ethanol produced), comparable to that of engineered microbes thus far. Strain TG57 exhibits significant advances including unique genes responsible for a new butyrate synthesis pathway, no carbon catabolite repression, and the absence of genes responsible for acetone synthesis (which is observed as the main by-product in most Clostridium strains known today). Furthermore, the use of glucose analog 2-deoxyglucose posed a selection pressure to facilitate isolation of strain TG57 with deletion/silencing of carbon catabolite repressor genes-the ccr and xylR genes-and thus is able to simultaneously ferment glucose, xylose, and arabinose to produce butanol (7.33 g/liter) as the sole solvent. Combined analysis of genomic and transcriptomic data revealed unusual aspects of genome organization, numerous determinants for unique bioconversions, regulation of central metabolic pathways, and distinct transcriptomic profiles. This study provides a genome-level understanding of how cellulose is metabolized by T. thermosaccharolyticum and sheds light on the potential of competitive and sustainable biofuel production.
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Affiliation(s)
- Tinggang Li
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Chen Zhang
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
| | - Kun-Lin Yang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576
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32
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Godoy AS, Pereira CS, Ramia MP, Silveira RL, Camilo CM, Kadowaki MA, Lange L, Busk PK, Nascimento AS, Skaf MS, Polikarpov I. Structure, computational and biochemical analysis of PcCel45A endoglucanase from Phanerochaete chrysosporium and catalytic mechanisms of GH45 subfamily C members. Sci Rep 2018; 8:3678. [PMID: 29487297 PMCID: PMC5829257 DOI: 10.1038/s41598-018-21798-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 01/23/2018] [Indexed: 11/09/2022] Open
Abstract
The glycoside hydrolase family 45 (GH45) of carbohydrate modifying enzymes is mostly comprised of β-1,4-endoglucanases. Significant diversity between the GH45 members has prompted the division of this family into three subfamilies: A, B and C, which may differ in terms of the mechanism, general architecture, substrate binding and cleavage. Here, we use a combination of X-ray crystallography, bioinformatics, enzymatic assays, molecular dynamics simulations and site-directed mutagenesis experiments to characterize the structure, substrate binding and enzymatic specificity of the GH45 subfamily C endoglucanase from Phanerochaete chrysosporium (PcCel45A). We investigated the role played by different residues in the binding of the enzyme to cellulose oligomers of different lengths and examined the structural characteristics and dynamics of PcCel45A that make subfamily C so dissimilar to other members of the GH45 family. Due to the structural similarity shared between PcCel45A and domain I of expansins, comparative analysis of their substrate binding was also carried out. Our bioinformatics sequence analyses revealed that the hydrolysis mechanisms in GH45 subfamily C is not restricted to use of the imidic asparagine as a general base in the "Newton's cradle" catalytic mechanism recently proposed for this subfamily.
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Affiliation(s)
- Andre S Godoy
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, São Paulo, Brazil
| | - Caroline S Pereira
- Institute of Chemistry, University of Campinas, Campinas, 13084-862, São Paulo, Brazil
| | - Marina Paglione Ramia
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, São Paulo, Brazil
| | - Rodrigo L Silveira
- Institute of Chemistry, University of Campinas, Campinas, 13084-862, São Paulo, Brazil
| | - Cesar M Camilo
- Centro de Tecnologia Canavieira, Fazenda Santo Antonio, PO Box 162, 13400-970, Piracicaba, São Paulo, Brazil
| | - Marco A Kadowaki
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, São Paulo, Brazil
| | - Lene Lange
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kgs, Lyngby, Denmark
| | - Peter K Busk
- Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts Plads, Building 229, 2800 Kgs, Lyngby, Denmark
| | - Alessandro S Nascimento
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, São Paulo, Brazil
| | - Munir S Skaf
- Institute of Chemistry, University of Campinas, Campinas, 13084-862, São Paulo, Brazil
| | - Igor Polikarpov
- São Carlos Institute of Physics, University of São Paulo, São Carlos 13566-590, São Paulo, Brazil.
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33
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Shahab RL, Luterbacher JS, Brethauer S, Studer MH. Consolidated bioprocessing of lignocellulosic biomass to lactic acid by a synthetic fungal-bacterial consortium. Biotechnol Bioeng 2018; 115:1207-1215. [DOI: 10.1002/bit.26541] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 12/11/2017] [Accepted: 01/05/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Robert L. Shahab
- Laboratory of Sustainable and Catalytic Processing; Institute of Chemical Sciences and Engineering; École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
- Laboratory of Biofuels and Biochemicals; School of Agricultural, Forest and Food Sciences; Bern University of Applied Sciences (BFH); Zollikofen Switzerland
| | - Jeremy S. Luterbacher
- Laboratory of Sustainable and Catalytic Processing; Institute of Chemical Sciences and Engineering; École Polytechnique Fédérale de Lausanne (EPFL); Lausanne Switzerland
| | - Simone Brethauer
- Laboratory of Biofuels and Biochemicals; School of Agricultural, Forest and Food Sciences; Bern University of Applied Sciences (BFH); Zollikofen Switzerland
| | - Michael H. Studer
- Laboratory of Biofuels and Biochemicals; School of Agricultural, Forest and Food Sciences; Bern University of Applied Sciences (BFH); Zollikofen Switzerland
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34
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Expression of a Cellobiose Phosphorylase from Thermotoga maritima in Caldicellulosiruptor bescii Improves the Phosphorolytic Pathway and Results in a Dramatic Increase in Cellulolytic Activity. Appl Environ Microbiol 2018; 84:AEM.02348-17. [PMID: 29101202 DOI: 10.1128/aem.02348-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 11/01/2017] [Indexed: 01/16/2023] Open
Abstract
Members of the genus Caldicellulosiruptor have the ability to deconstruct and grow on lignocellulosic biomass without conventional pretreatment. A genetically tractable species, Caldicellulosiruptor bescii, was recently engineered to produce ethanol directly from switchgrass. C. bescii contains more than 50 glycosyl hydrolases and a suite of extracellular enzymes for biomass deconstruction, most prominently CelA, a multidomain cellulase that uses a novel mechanism to deconstruct plant biomass. Accumulation of cellobiose, a product of CelA during growth on biomass, inhibits cellulase activity. Here, we show that heterologous expression of a cellobiose phosphorylase from Thermotoga maritima improves the phosphorolytic pathway in C. bescii and results in synergistic activity with endogenous enzymes, including CelA, to increase cellulolytic activity and growth on crystalline cellulose.IMPORTANCE CelA is the only known cellulase to function well on highly crystalline cellulose and it uses a mechanism distinct from those of other cellulases, including fungal cellulases. Also unlike fungal cellulases, it functions at high temperature and, in fact, outperforms commercial cellulase cocktails. Factors that inhibit CelA during biomass deconstruction are significantly different than those that impact the performance of fungal cellulases and commercial mixtures. This work contributes to understanding of cellulase inhibition and enzyme function and will suggest a rational approach to engineering optimal activity.
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35
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Westh P, Borch K, Sørensen T, Tokin R, Kari J, Badino S, Cavaleiro MA, Røjel N, Christensen S, Vesterager CS, Schiano-di-Cola C. Thermoactivation of a cellobiohydrolase. Biotechnol Bioeng 2018; 115:831-838. [PMID: 29240229 DOI: 10.1002/bit.26513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/21/2017] [Accepted: 12/04/2017] [Indexed: 01/11/2023]
Abstract
We have measured activity and substrate affinity of the thermostable cellobiohydrolase, Cel7A, from Rasamsonia emersonii over a broad range of temperatures. For the wild type enzyme, which does not have a Carbohydrate Binding Module (CBM), higher temperature only led to moderately increased activity against cellulose, and we ascribed this to a pronounced, temperature induced desorption of enzyme from the substrate surface. We also tested a "high affinity" variant of R. emersonii Cel7A with a linker and CBM from a related enzyme. At room temperature, the activity of the variant was similar to the wild type, but the variant was more accelerated by temperature and about two-fold faster around 70 °C. This better thermoactivation of the high-affinity variant could not be linked to differences in stability or the catalytic process, but coincided with less desorption as temperature increased. Based on these observations and earlier reports on moderate thermoactivation of cellulases, we suggest that better cellulolytic activity at industrially relevant temperatures may be attained by engineering improved substrate affinity into enzymes that already possess good thermostability.
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Affiliation(s)
- Peter Westh
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | | | - Trine Sørensen
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | - Radina Tokin
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | - Jeppe Kari
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | - Silke Badino
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | | | - Nanna Røjel
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | - Stefan Christensen
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
| | - Cynthia S Vesterager
- Department of Science and Environment, INM, Universitetsvej 1, Roskilde, Denmark
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36
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Kumar D, Murthy GS. Development and validation of a stochastic molecular model of cellulose hydrolysis by action of multiple cellulase enzymes. BIORESOUR BIOPROCESS 2017. [DOI: 10.1186/s40643-017-0184-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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37
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Acosta-Sampson L, Döring K, Lin Y, Yu VY, Bukau B, Kramer G, Cate JHD. Role for ribosome-associated complex and stress-seventy subfamily B (RAC-Ssb) in integral membrane protein translation. J Biol Chem 2017; 292:19610-19627. [PMID: 28972146 DOI: 10.1074/jbc.m117.813857] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Indexed: 01/04/2023] Open
Abstract
Targeting of most integral membrane proteins to the endoplasmic reticulum is controlled by the signal recognition particle, which recognizes a hydrophobic signal sequence near the protein N terminus. Proper folding of these proteins is monitored by the unfolded protein response and involves protein degradation pathways to ensure quality control. Here, we identify a new pathway for quality control of major facilitator superfamily transporters that occurs before the first transmembrane helix, the signal sequence recognized by the signal recognition particle, is made by the ribosome. Increased rates of translation elongation of the N-terminal sequence of these integral membrane proteins can divert the nascent protein chains to the ribosome-associated complex and stress-seventy subfamily B chaperones. We also show that quality control of integral membrane proteins by ribosome-associated complex-stress-seventy subfamily B couples translation rate to the unfolded protein response, which has implications for understanding mechanisms underlying human disease and protein production in biotechnology.
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Affiliation(s)
| | - Kristina Döring
- the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany.,the German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany, and
| | - Yuping Lin
- From the Departments of Molecular and Cell Biology and
| | - Vivian Y Yu
- From the Departments of Molecular and Cell Biology and
| | - Bernd Bukau
- the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany.,the German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany, and
| | - Günter Kramer
- the Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg D-69120, Germany.,the German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg D-69120, Germany, and
| | - Jamie H D Cate
- From the Departments of Molecular and Cell Biology and .,Chemistry, University of California, Berkeley, California 94720.,the Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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Kim SK, Chung D, Himmel ME, Bomble YJ, Westpheling J. Heterologous expression of a β-D-glucosidase in Caldicellulosiruptor bescii has a surprisingly modest effect on the activity of the exoproteome and growth on crystalline cellulose. J Ind Microbiol Biotechnol 2017; 44:1643-1651. [PMID: 28942503 DOI: 10.1007/s10295-017-1982-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/14/2017] [Indexed: 11/28/2022]
Abstract
Members of the genus Caldicellulosiruptor are the most thermophilic cellulolytic bacteria so far described and are capable of efficiently utilizing complex lignocellulosic biomass without conventional pretreatment. Previous studies have shown that accumulation of high concentrations of cellobiose and, to a lesser extent, cellotriose, inhibits cellulase activity both in vivo and in vitro and high concentrations of cellobiose are present in C. bescii fermentations after 90 h of incubation. For some cellulolytic microorganisms, β-D-glucosidase is essential for the efficient utilization of cellobiose as a carbon source and is an essential enzyme in commercial preparations for efficient deconstruction of plant biomass. In spite of its ability to grow efficiently on crystalline cellulose, no extracellular β-D-glucosidase or its GH1 catalytic domain could be identified in the C. bescii genome. To investigate whether the addition of a secreted β-D-glucosidase would improve growth and cellulose utilization by C. bescii, we cloned and expressed a thermostable β-D-glucosidase from Acidothermus cellulolyticus (Acel_0133) in C. bescii using the CelA signal sequence for protein export. The effect of this addition was modest, suggesting that β-D-glucosidase is not rate limiting for cellulose deconstruction and utilization by C. bescii.
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Affiliation(s)
- Sun-Ki Kim
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA.,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Daehwan Chung
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA.,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA.,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Yannick J Bomble
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, USA.,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Janet Westpheling
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA. .,The BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
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Scott F, Aroca G, Caballero JA, Conejeros R. A generalized disjunctive programming framework for the optimal synthesis and analysis of processes for ethanol production from corn stover. BIORESOURCE TECHNOLOGY 2017; 236:212-224. [PMID: 28411493 DOI: 10.1016/j.biortech.2017.03.180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/28/2017] [Accepted: 03/29/2017] [Indexed: 06/07/2023]
Abstract
The aim of this study is to analyze the techno-economic performance of process configurations for ethanol production involving solid-liquid separators and reactors in the saccharification and fermentation stage, a family of process configurations where few alternatives have been proposed. Since including these process alternatives creates a large number of possible process configurations, a framework for process synthesis and optimization is proposed. This approach is supported on kinetic models fed with experimental data and a plant-wide techno-economic model. Among 150 process configurations, 40 show an improved MESP compared to a well-documented base case (BC), almost all include solid separators and some show energy retrieved in products 32% higher compared to the BC. Moreover, 16 of them also show a lower capital investment per unit of ethanol produced per year. Several of the process configurations found in this work have not been reported in the literature.
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Affiliation(s)
- Felipe Scott
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2085, Valparaíso, Chile; Bioenercel S.A. Barrio Universitario s/n, Ideaincuba Building, Concepción, Chile.
| | - Germán Aroca
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2085, Valparaíso, Chile; Bioenercel S.A. Barrio Universitario s/n, Ideaincuba Building, Concepción, Chile
| | - José Antonio Caballero
- Department of Chemical Engineering, University of Alicante, Ap Correos 99, 03080 Alicante, Spain
| | - Raúl Conejeros
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2085, Valparaíso, Chile; Bioenercel S.A. Barrio Universitario s/n, Ideaincuba Building, Concepción, Chile
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40
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Synergies in coupled hydrolysis and fermentation of cellulose using a Trichoderma reesei enzyme preparation and a recombinant Saccharomyces cerevisiae strain. World J Microbiol Biotechnol 2017; 33:140. [DOI: 10.1007/s11274-017-2308-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 06/01/2017] [Indexed: 11/27/2022]
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41
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Badino SF, Christensen SJ, Kari J, Windahl MS, Hvidt S, Borch K, Westh P. Exo-exo synergy between Cel6A and Cel7A fromHypocrea jecorina: Role of carbohydrate binding module and the endo-lytic character of the enzymes. Biotechnol Bioeng 2017; 114:1639-1647. [DOI: 10.1002/bit.26276] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Silke F. Badino
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Stefan J. Christensen
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Jeppe Kari
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Michael S. Windahl
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
- Novozymes A/S; Bagsvaerd Denmark
| | - Søren Hvidt
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | | | - Peter Westh
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
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Kuusk S, Väljamäe P. When substrate inhibits and inhibitor activates: implications of β-glucosidases. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:7. [PMID: 28053666 PMCID: PMC5209912 DOI: 10.1186/s13068-016-0690-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/16/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND β-glucosidases (BGs) catalyze the hydrolysis of β-glycosidic bonds in glucose derivatives. They constitute an important group of enzymes with biotechnological interest like supporting cellulases in degradation of lignocellulose to fermentable sugars. In the latter context, the glucose tolerant BGs are of particular interest. These BGs often show peculiar kinetics, including inhibitory effects of substrates and activating effects of inhibitors, such as glucose or xylose. The mechanisms behind the activating/inhibiting effects are poorly understood. The nonproductive binding of substrate is expected in cases where enzymes with multiple consecutive binding subsites are studied on substrates with a low degree of polymerization. The effects of inhibitors to BGs exerting nonproductive binding of substrate have not been discussed in the literature before. RESULTS Here, we performed analyses of different reaction schemes using the catalysis by retaining BGs as a model. We found that simple competition of inhibitor with nonproductive binding of substrate can account for the activation of enzyme by inhibitor without involving any allosteric effects. The transglycosylation to inhibitor was also able to explain the activating effect of inhibitor. For both mechanisms, the activation was caused by the increase of kcat with increasing inhibitor concentration, while kcat/Km always decreased. Therefore, the activation by inhibitor was more pronounced at high substrate concentrations. The possible contribution of the two mechanisms in the activation by inhibitor was dependent on the rate-limiting step of glycosidic bond hydrolysis as well as on whether and which glucose-unit-binding subsites are interacting. CONCLUSION Knowledge on the mechanisms of the activating/inhibiting effects of inhibitors helps the rational engineering and selection of BGs for biotechnological applications. Provided that the catalysis is consistent with the reaction schemes addressed here and underlying assumptions, the mechanism of activation by inhibitor reported here is applicable for all enzymes exerting nonproductive binding of substrate.
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Affiliation(s)
- Silja Kuusk
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, 51010 Tartu, Estonia
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, 51010 Tartu, Estonia
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Karnaouri A, Muraleedharan MN, Dimarogona M, Topakas E, Rova U, Sandgren M, Christakopoulos P. Recombinant expression of thermostable processive MtEG5 endoglucanase and its synergism with MtLPMO from Myceliophthora thermophila during the hydrolysis of lignocellulosic substrates. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:126. [PMID: 28515785 PMCID: PMC5432998 DOI: 10.1186/s13068-017-0813-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/08/2017] [Indexed: 05/02/2023]
Abstract
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.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Madhu Nair Muraleedharan
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Maria Dimarogona
- Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Evangelos Topakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
- Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
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Kari J, Kont R, Borch K, Buskov S, Olsen JP, Cruyz-Bagger N, Väljamäe P, Westh P. Anomeric Selectivity and Product Profile of a Processive Cellulase. Biochemistry 2016; 56:167-178. [PMID: 28026938 DOI: 10.1021/acs.biochem.6b00636] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cellobiohydrolases (CBHs) make up an important group of enzymes for both natural carbon cycling and industrial deconstruction of lignocellulosic biomass. The consecutive hydrolysis of one cellulose strand relies on an intricate pattern of enzyme-substrate interactions in the long, tunnel-shaped binding site of the CBH. In this work, we have investigated the initial complexation mode with cellulose of the most thoroughly studied CBH, Cel7A from Hypocrea jecorina (HjCel7A). We found that HjCel7A predominantly produces glucose when it initiates a processive run on insoluble microcrystalline cellulose, confirming the validity of an even and odd product ratio as an estimate of processivity. Moreover, the glucose released from cellulose was predominantly α-glucose. A link between the initial binding mode of the enzyme and the reducing end configuration was investigated by inhibition studies with the two anomers of cellobiose. A clear preference for β-cellobiose in product binding site +2 was observed for HjCel7A, but not the homologous endoglucanase, HjCe7B. Possible relationships between this anomeric preference in the product site and the prevalence of odd-numbered initial-cut products are discussed, and a correlation between processivity and anomer selectivity is proposed.
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Affiliation(s)
- Jeppe Kari
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
| | - Riin Kont
- Institute of Molecular and Cell Biology, University of Tartu , Tartu, Estonia
| | - Kim Borch
- Novozymes A/S , Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Steen Buskov
- Novozymes A/S , Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Johan Pelck Olsen
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
| | | | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu , Tartu, Estonia
| | - Peter Westh
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
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Baramee S, Teeravivattanakit T, Phitsuwan P, Waeonukul R, Pason P, Tachaapaikoon C, Kosugi A, Sakka K, Ratanakhanokchai K. A novel GH6 cellobiohydrolase from Paenibacillus curdlanolyticus B-6 and its synergistic action on cellulose degradation. Appl Microbiol Biotechnol 2016; 101:1175-1188. [PMID: 27743043 DOI: 10.1007/s00253-016-7895-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 09/12/2016] [Accepted: 09/25/2016] [Indexed: 11/30/2022]
Abstract
We recently discovered a novel glycoside hydrolase family 6 (GH6) cellobiohydrolase from Paenibacillus curdlanolyticus B-6 (PcCel6A), which is rarely found in bacteria. This enzyme is a true exo-type cellobiohydrolase which exhibits high substrate specificity on amorphous cellulose and low substrate specificity on crystalline cellulose, while this showed no activity on substitution substrates, carboxymethyl cellulose and xylan, distinct from all other known GH6 cellobiohydrolases. Product profiles, HPLC analysis of the hydrolysis products and a schematic drawing of the substrate-binding subsites catalysing cellooligosaccharides can explain the new mode of action of this enzyme which prefers to hydrolyse cellopentaose. PcCel6A was not inhibited by glucose or cellobiose at concentrations up to 300 and 100 mM, respectively. A good synergistic effect for glucose production was found when PcCel6A acted together with processive endoglucanase Cel9R from Clostridium thermocellum and β-glucosidase CglT from Thermoanaerobacter brockii. These properties of PcCel6A make it a suitable candidate for industrial application in the cellulose degradation process.
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Affiliation(s)
- Sirilak Baramee
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Thitiporn Teeravivattanakit
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Paripok Phitsuwan
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Rattiya Waeonukul
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Patthra Pason
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Chakrit Tachaapaikoon
- Pilot Plant Development and Training Institute, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand
| | - Akihiko Kosugi
- Biological Resources and Post-Harvest Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki, 305-8686, Japan
| | - Kazuo Sakka
- Graduated School of Bioresources, Mie University, Tsu, Mie, 514-8507, Japan
| | - Khanok Ratanakhanokchai
- School of Bioresources and Technology, King Mongkut's University of Technology Thonburi, Bangkok, 10150, Thailand.
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Sant’Ana da Silva A, Fernandes de Souza M, Ballesteros I, Manzanares P, Ballesteros M, P. S. Bon E. High-solids content enzymatic hydrolysis of hydrothermally pretreated sugarcane bagasse using a laboratory-made enzyme blend and commercial preparations. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.07.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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47
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Cruys-Bagger N, Alasepp K, Andersen M, Ottesen J, Borch K, Westh P. Rate of Threading a Cellulose Chain into the Binding Tunnel of a Cellulase. J Phys Chem B 2016; 120:5591-600. [DOI: 10.1021/acs.jpcb.6b01877] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicolaj Cruys-Bagger
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Kadri Alasepp
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Morten Andersen
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Johnny Ottesen
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
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48
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Hildebrand A, Bennett Addison J, Kasuga T, Fan Z. Cellobionic acid inhibition of cellobiohydrolase I and cellobiose dehydrogenase. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2016.01.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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49
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Olsen JP, Alasepp K, Kari J, Cruys-Bagger N, Borch K, Westh P. Mechanism of product inhibition for cellobiohydrolase Cel7A during hydrolysis of insoluble cellulose. Biotechnol Bioeng 2016; 113:1178-86. [DOI: 10.1002/bit.25900] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 11/23/2015] [Accepted: 11/29/2015] [Indexed: 01/10/2023]
Affiliation(s)
- Johan P. Olsen
- Research Unit for Functional Biomaterials; Roskilde University; NSM, 1 Universitetsvej, Build. 28 DK-4000 Roskilde Denmark
| | - Kadri Alasepp
- Research Unit for Functional Biomaterials; Roskilde University; NSM, 1 Universitetsvej, Build. 28 DK-4000 Roskilde Denmark
| | - Jeppe Kari
- Research Unit for Functional Biomaterials; Roskilde University; NSM, 1 Universitetsvej, Build. 28 DK-4000 Roskilde Denmark
| | - Nicolaj Cruys-Bagger
- Research Unit for Functional Biomaterials; Roskilde University; NSM, 1 Universitetsvej, Build. 28 DK-4000 Roskilde Denmark
- Novozymes A/S; Bagsvaerd Denmark
| | | | - Peter Westh
- Research Unit for Functional Biomaterials; Roskilde University; NSM, 1 Universitetsvej, Build. 28 DK-4000 Roskilde Denmark
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50
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