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Rehman F, Sajjad M, Akhtar MW. Orientation of Cel5A and Xyn10B in a fusion construct is important in facilitating synergistic degradation of plant biomass polysaccharides. J Biosci Bioeng 2023; 135:274-281. [PMID: 36828688 DOI: 10.1016/j.jbiosc.2022.11.002] [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: 09/02/2022] [Revised: 10/26/2022] [Accepted: 11/03/2022] [Indexed: 02/25/2023]
Abstract
One approach to achieve efficient and economical saccharification of plant biomass would be using thermostable and multifunctional enzymes from hyperthermophiles such as Thermotoga maritima. Thus, the bifunctional constructs, Cel5A-Xyn10B and Xyn10B-Cel5A, were produced by fusing cellulase Cel5A at the N- and C-terminals of xylanase Xyn10B, respectively. The Cel5A-Xyn10B fusion construct showed cellulase activity of 1483 U μmol-1 against carboxymethyl cellulose, which was nearly the same as that of Cel5A in the free form. However, xylanase activity of this construct increased by 2-fold against beechwood xylan as compared to that of Xyn10B in free form. The synergistic effect between Cel5A and Xyn10B in the form of Cel5A-Xyn10B fusion resulted an overall increase in the release of reducing sugars. However, Xyn10B-Cel5A showed about 60% decrease in activities of both the component enzymes as compared to their activities in the free form. Both the fusion constructs were active in a wide range of pH from 4.0 to 9.0 and temperatures from 50 to 90 °C. Nearly 80% of cellulase and xylanase activities were retained in Cel5A-Xyn10B fusion after incubation at 60 °C for 1 h. Secondary structures of the component enzymes were retained in the Cel5A-Xyn10B fusion as observed by circular dichroism spectroscopy. Docking and simulation studies suggested that the enhanced xylanase activity in Cel5A-Xyn10B was due to the high binding energy, favorable orientation of the active sites, as well as relative positioning of the active site residues of Cel5A and Xyn10B in closer vicinity, which facilitated the substrate channeling.
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Affiliation(s)
- Fatima Rehman
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan
| | - Muhammad Sajjad
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan
| | - Muhammad Waheed Akhtar
- School of Biological Sciences, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan.
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2
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Benatti ALT, Polizeli MDLTDM. Lignocellulolytic Biocatalysts: The Main Players Involved in Multiple Biotechnological Processes for Biomass Valorization. Microorganisms 2023; 11:microorganisms11010162. [PMID: 36677454 PMCID: PMC9864444 DOI: 10.3390/microorganisms11010162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/11/2022] [Accepted: 12/26/2022] [Indexed: 01/10/2023] Open
Abstract
Human population growth, industrialization, and globalization have caused several pressures on the planet's natural resources, culminating in the severe climate and environmental crisis which we are facing. Aiming to remedy and mitigate the impact of human activities on the environment, the use of lignocellulolytic enzymes for biofuel production, food, bioremediation, and other various industries, is presented as a more sustainable alternative. These enzymes are characterized as a group of enzymes capable of breaking down lignocellulosic biomass into its different monomer units, making it accessible for bioconversion into various products and applications in the most diverse industries. Among all the organisms that produce lignocellulolytic enzymes, microorganisms are seen as the primary sources for obtaining them. Therefore, this review proposes to discuss the fundamental aspects of the enzymes forming lignocellulolytic systems and the main microorganisms used to obtain them. In addition, different possible industrial applications for these enzymes will be discussed, as well as information about their production modes and considerations about recent advances and future perspectives in research in pursuit of expanding lignocellulolytic enzyme uses at an industrial scale.
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3
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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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Srivastava A, Nagar P, Rathore S, Adlakha N. The Linker Region Promotes Activity and Binding Efficiency of Modular LPMO towards Polymeric Substrate. Microbiol Spectr 2022; 10:e0269721. [PMID: 35080440 PMCID: PMC8791183 DOI: 10.1128/spectrum.02697-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 12/31/2021] [Indexed: 12/03/2022] Open
Abstract
Lytic polysaccharide monooxygenases (LPMOs) mediate oxidative degradation of plant polysaccharides. The genes encoding LPMOs are most commonly arranged with one catalytic domain, while a few are found tethered to additional noncatalytic units, i.e., cellulase linker and carbohydrate-binding module (CBM). The presence of CBM is known to facilitate catalysis by directing the enzymes toward cellulosic polymer, while the role of linkers is poorly understood. Based on limited experimental evidence, linkers are believed to serve merely as flexible spacers between the structured domains. Thus, this study aims to unravel the role of the linker regions present in LPMO sequences. For this, we analyzed the genome of Botrytis cinerea and found 9 genes encoding cellulose lytic monooxygenases (AA9 family), of which BcAA9C was overexpressed in cellulose-inducible conditions. We designed variants of flLPMO (full-length enzyme) with truncation of either linker or CBM to examine the role of linker in activity, binding, and thermal stability of the associated monooxygenase. Biochemical assays predicted that the deletion of linker does not impact the potential of flLPMO for catalyzing the oxidation of Amplex Red, but that it does have a major influence on the capability of flLPMO to degrade recalcitrant polysaccharide substrate. Langmuir isotherm and SEM analysis demonstrated that linker domain aids in polysaccharide binding during flLPMO-mediated deconstruction of plant cell wall. Interestingly, linker domain was also found to contribute toward the thermostability of flLPMO. Overall, our study reveals that linker is not merely a spacer, but plays a key role in LPMO-mediated biomass fibrillation; these findings are broadly applicable to other polysaccharide-degrading enzymes. IMPORTANCE The polysaccharide-disintegrating carbohydrate-active enzymes (CAZymes) are often found with multimodular architecture, where the catalytic domain is connected to an accessory CBM domain with the help of a flexible linker region. So far, the linker has been understood merely as a flexible spacer between the two domains. Therefore, the current study is designed to determine the role of linker in polysaccharide fibrillation. To conceive this study, we have selected LPMO as a model enzyme, as it is not only an industrially relevant enzyme but it also harbors a catalytic domain, linker region, and CBM domain. The present study highlighted the crucial and indispensable role of the linker region in mediating polysaccharide disintegration. Considering its role in binding, thermostability, and activity toward polysaccharide substrate, we propose linker as a potential candidate for future CAZyme engineering.
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Affiliation(s)
- Aishwarya Srivastava
- Synthetic Biology and Bioprocessing Laboratory, Regional Centre for Biotechnology, NCR-Biotech Cluster, Faridabad, Haryana, India
| | - Pragya Nagar
- Synthetic Biology and Bioprocessing Laboratory, Regional Centre for Biotechnology, NCR-Biotech Cluster, Faridabad, Haryana, India
| | - Sumit Rathore
- Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India
| | - Nidhi Adlakha
- Synthetic Biology and Bioprocessing Laboratory, Regional Centre for Biotechnology, NCR-Biotech Cluster, Faridabad, Haryana, India
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5
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Biorefinery Gets Hot: Thermophilic Enzymes and Microorganisms for Second-Generation Bioethanol Production. Processes (Basel) 2021. [DOI: 10.3390/pr9091583] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
To mitigate the current global energy and the environmental crisis, biofuels such as bioethanol have progressively gained attention from both scientific and industrial perspectives. However, at present, commercialized bioethanol is mainly derived from edible crops, thus raising serious concerns given its competition with feed production. For this reason, lignocellulosic biomasses (LCBs) have been recognized as important alternatives for bioethanol production. Because LCBs supply is sustainable, abundant, widespread, and cheap, LCBs-derived bioethanol currently represents one of the most viable solutions to meet the global demand for liquid fuel. However, the cost-effective conversion of LCBs into ethanol remains a challenge and its implementation has been hampered by several bottlenecks that must still be tackled. Among other factors related to the challenging and variable nature of LCBs, we highlight: (i) energy-demanding pretreatments, (ii) expensive hydrolytic enzyme blends, and (iii) the need for microorganisms that can ferment mixed sugars. In this regard, thermophiles represent valuable tools to overcome some of these limitations. Thus, the aim of this review is to provide an overview of the state-of-the-art technologies involved, such as the use of thermophilic enzymes and microorganisms in industrial-relevant conditions, and to propose possible means to implement thermophiles into second-generation ethanol biorefineries that are already in operation.
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6
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Hu S, Wang Z, Wang D, Wang J, Hong J. The development of a heterologous gene expression system in thermophilic fungus Thermoascus aurantiacus. 3 Biotech 2021; 11:414. [PMID: 34485007 PMCID: PMC8374019 DOI: 10.1007/s13205-021-02963-w] [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: 11/29/2020] [Accepted: 08/05/2021] [Indexed: 10/20/2022] Open
Abstract
Thermoascus aurantiacus is a thermophilic fungus that belongs to the ascomycetous class and has attracted increasing interest for its ability to produce thermostable cellulolytic enzymes and growth at elevated temperatures. However, studies on this organism have been limited because of the lack of a genetic manipulation system. Here, we developed a polyethylene glycol (PEG)-mediated transformation system for T. aurantiacus based on an orotidine-5'-monophosphate decarboxylase (pyrG)-deficient mutant, with this method achieving a transformation efficiency of 33 ± 3 transformants per microgram of DNA. Intracellular or secretory expression of heterologous proteins, including green fluorescent protein, β-galactosidase and α-amylase, in T. aurantiacus was successful under the inducible endogenous cellobiohydrolase and endoglucanase gene promoter or the constitutive heterologous pyruvate decarboxylase and enolase gene promoter from Trichoderma reesei. To the best of our knowledge, this is the first report on PEG-mediated transformation of T. aurantiacus, which sets the foundation for strain improvement for biotechnological applications and functional genomic studies. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s13205-021-02963-w.
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Affiliation(s)
- Shenglin Hu
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 People’s Republic of China
- Hefei National Laboratory for Physical Science At the Microscale, Hefei, Anhui 230026 People’s Republic of China
| | - Zhefan Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 People’s Republic of China
| | - Dongmei Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 People’s Republic of China
| | - Jichao Wang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 People’s Republic of China
| | - Jiong Hong
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 People’s Republic of China
- Hefei National Laboratory for Physical Science At the Microscale, Hefei, Anhui 230026 People’s Republic of China
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7
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Østby H, Hansen LD, Horn SJ, Eijsink VGH, Várnai A. Enzymatic processing of lignocellulosic biomass: principles, recent advances and perspectives. J Ind Microbiol Biotechnol 2020; 47:623-657. [PMID: 32840713 PMCID: PMC7658087 DOI: 10.1007/s10295-020-02301-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023]
Abstract
Efficient saccharification of lignocellulosic biomass requires concerted development of a pretreatment method, an enzyme cocktail and an enzymatic process, all of which are adapted to the feedstock. Recent years have shown great progress in most aspects of the overall process. In particular, increased insights into the contributions of a wide variety of cellulolytic and hemicellulolytic enzymes have improved the enzymatic processing step and brought down costs. Here, we review major pretreatment technologies and different enzyme process setups and present an in-depth discussion of the various enzyme types that are currently in use. We pay ample attention to the role of the recently discovered lytic polysaccharide monooxygenases (LPMOs), which have led to renewed interest in the role of redox enzyme systems in lignocellulose processing. Better understanding of the interplay between the various enzyme types, as they may occur in a commercial enzyme cocktail, is likely key to further process improvements.
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Affiliation(s)
- Heidi Østby
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Line Degn Hansen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Svein J Horn
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway
| | - Anikó Várnai
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432, Aas, Norway.
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8
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Enzymatic Hydrolysis of Softwood Derived Paper Sludge by an In Vitro Recombinant Cellulase Cocktail for the Production of Fermentable Sugars. Catalysts 2020. [DOI: 10.3390/catal10070775] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Paper sludge is an attractive biomass feedstock for bioconversion to ethanol due to its low cost and the lack of pretreatment required for its bioprocessing. This study assessed the use of a recombinant cellulase cocktail (mono-components: S. cerevisiae-derived PcBGL1B (BGL), TeCel7A (CBHI), ClCel6A (CBHII) and TrCel5A (EGII) mono-component cellulase enzymes) for the efficient saccharification of softwood-derived paper sludge to produce fermentable sugars. The paper sludge mainly contained 74.3% moisture and 89.7% (per dry mass (DM)) glucan with a crystallinity index of 91.5%. The optimal protein ratio for paper sludge hydrolysis was observed at 9.4: 30.2: 30.2: 30.2% for BGL: CBHI: CBHII: EGII. At a protein loading of 7.5 mg/g DW paper sludge, the yield from hydrolysis was approximately 80%, based on glucan, with scanning electron microscopy micrographs indicating a significant alteration in the microfibril size (length reduced from ≥ 2 mm to 93 µm) of the paper sludge. The paper sludge hydrolysis potential of the Opt CelMix (formulated cellulase cocktail) was similar to the commercial Cellic CTec2® and Celluclast® 1.5 L cellulase preparations and better than Viscozyme® L. Low enzyme loadings (15 mg/g paper sludge) of the Opt CelMix and solid loadings ranging between 1 to 10% (w/v) rendered over 80% glucan conversion. The high glucose yields attained on the paper sludge by the low enzyme loading of the Opt CelMix demonstrated the value of enzyme cocktail optimisation on specific substrates for efficient cellulose conversion to fermentable sugars.
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9
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de Vries RP, Mäkelä MR. Genomic and Postgenomic Diversity of Fungal Plant Biomass Degradation Approaches. Trends Microbiol 2020; 28:487-499. [PMID: 32396827 DOI: 10.1016/j.tim.2020.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/15/2019] [Accepted: 01/16/2020] [Indexed: 10/25/2022]
Abstract
Plant biomass degradation by fungi is a widely studied and applied field of science, due to its relevance for the global carbon cycle and many biotechnological applications. Before the genome era, many of the in-depth studies focused on a relatively small number of species, whereas now, many species can be addressed in detail, revealing the large variety in the approach used by fungi to degrade plant biomass. This variation is found at many levels and includes genomic adaptation to the preferred biomass component, but also different approaches to degrade this component by diverse sets of activities encoded in the genome. Even larger differences have been observed using transcriptome and proteome studies, even between closely related species, suggesting a high level of adaptation in individual species. A better understanding of the drivers of this diversity could be highly valuable in developing more efficient biotechnology approaches for the enzymatic conversion of plant biomass.
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Affiliation(s)
- Ronald P de Vries
- Fungal Physiology, Westerdijk Fungal Biodiversity Institute & Fungal Molecular Physiology, Utrecht University, Utrecht, The Netherlands.
| | - Miia R Mäkelä
- Department of Microbiology, University of Helsinki, Helsinki, Finland
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10
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Singhvi MS, Gokhale DV. Lignocellulosic biomass: Hurdles and challenges in its valorization. Appl Microbiol Biotechnol 2019; 103:9305-9320. [DOI: 10.1007/s00253-019-10212-7] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 10/17/2019] [Accepted: 10/20/2019] [Indexed: 12/13/2022]
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11
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Wei H, Wang W, Alper HS, Xu Q, Knoshaug EP, Van Wychen S, Lin CY, Luo Y, Decker SR, Himmel ME, Zhang M. Ameliorating the Metabolic Burden of the Co-expression of Secreted Fungal Cellulases in a High Lipid-Accumulating Yarrowia lipolytica Strain by Medium C/N Ratio and a Chemical Chaperone. Front Microbiol 2019; 9:3276. [PMID: 30687267 PMCID: PMC6333634 DOI: 10.3389/fmicb.2018.03276] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 12/17/2018] [Indexed: 12/19/2022] Open
Abstract
Yarrowia lipolytica, known to accumulate lipids intracellularly, lacks the cellulolytic enzymes needed to break down solid biomass directly. This study aimed to evaluate the potential metabolic burden of expressing core cellulolytic enzymes in an engineered high lipid-accumulating strain of Y. lipolytica. Three fungal cellulases, Talaromyces emersonii-Trichoderma reesei chimeric cellobiohydrolase I (chimeric-CBH I), T. reesei cellobiohydrolase II (CBH II), and T. reesei endoglucanase II (EG II) were expressed using three constitutive strong promoters as a single integrative expression block in a recently engineered lipid hyper-accumulating strain of Y. lipolytica (HA1). In yeast extract-peptone-dextrose (YPD) medium, the resulting cellulase co-expressing transformant YL165-1 had the chimeric-CBH I, CBH II, and EG II secretion titers being 26, 17, and 132 mg L-1, respectively. Cellulase co-expression in YL165-1 in culture media with a moderate C/N ratio of ∼4.5 unexpectedly resulted in a nearly two-fold reduction in cellular lipid accumulation compared to the parental control strain, a sign of cellular metabolic drain. Such metabolic drain was ameliorated when grown in media with a high C/N ratio of 59 having a higher glucose utilization rate that led to approximately twofold more cell mass and threefold more lipid production per liter culture compared to parental control strain, suggesting cross-talk between cellulase and lipid production, both of which involve the endoplasmic reticulum (ER). Most importantly, we found that the chemical chaperone, trimethylamine N-oxide dihydride increased glucose utilization, cell mass and total lipid titer in the transformants, suggesting further amelioration of the metabolic drain. This is the first study examining lipid production in cellulase-expressing Y. lipolytica strains under various C/N ratio media and with a chemical chaperone highlighting the metabolic complexity for developing robust, cellulolytic and lipogenic yeast strains.
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Affiliation(s)
- Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Wei Wang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Hal S Alper
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, United States
| | - Qi Xu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Eric P Knoshaug
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Stefanie Van Wychen
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Chien-Yuan Lin
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Yonghua Luo
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Stephen R Decker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States
| | - Min Zhang
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, United States.,National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, United States
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12
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Expression and characterisation of a thermophilic endo-1,4-β-glucanase from Sulfolobus shibatae of potential industrial application. Mol Biol Rep 2018; 45:2201-2211. [DOI: 10.1007/s11033-018-4381-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/12/2018] [Indexed: 12/17/2022]
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13
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Marjamaa K, Kruus K. Enzyme biotechnology in degradation and modification of plant cell wall polymers. PHYSIOLOGIA PLANTARUM 2018; 164:106-118. [PMID: 29987848 DOI: 10.1111/ppl.12800] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 07/02/2018] [Accepted: 07/05/2018] [Indexed: 05/28/2023]
Abstract
Lignocelluloses are abundant raw materials for production of fuels, chemicals and materials. The purpose of this paper is to review the enzyme-types and enzyme-technologies studied and applied in the processing of the lignocelluloses into different products. The enzymes here are mostly glycoside hydrolases, esterases and different redox enzymes. Enzymatic hydrolysis of lignocellulosic polysaccharides to platform sugars has been widely studied leading to development of advanced commercial products for this purpose. Restricted hydrolysis or oxidation of cellulosic fibers have been applied in processing of pulps to paper products, nanocelluloses and textile fibers. Oxidation, transglycosylation and derivatization have been utilized in functionalization of fibers, cellulosic surfaces and polysaccharides. Enzymatic polymerization, depolymerization and grafting methods are being developed for lignin valorization.
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Affiliation(s)
- Kaisa Marjamaa
- VTT Technical Research Centre of Finland Ltd, PO Box 1000, Espoo, 02044, Finland
| | - Kristiina Kruus
- VTT Technical Research Centre of Finland Ltd, PO Box 1000, Espoo, 02044, Finland
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14
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Lopes A, Ferreira Filho E, Moreira L. An update on enzymatic cocktails for lignocellulose breakdown. J Appl Microbiol 2018; 125:632-645. [DOI: 10.1111/jam.13923] [Citation(s) in RCA: 93] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Revised: 03/20/2018] [Accepted: 05/14/2018] [Indexed: 12/01/2022]
Affiliation(s)
- A.M. Lopes
- Laboratory of Enzymology; Department of Cellular Biology; University of Brasília; Brasilia DF Brazil
| | - E.X. Ferreira Filho
- Laboratory of Enzymology; Department of Cellular Biology; University of Brasília; Brasilia DF Brazil
| | - L.R.S. Moreira
- Laboratory of Enzymology; Department of Cellular Biology; University of Brasília; Brasilia DF Brazil
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15
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Development of tailor-made synergistic cellulolytic enzyme system for saccharification of steam exploded sugarcane bagasse. J Biosci Bioeng 2018; 125:390-396. [DOI: 10.1016/j.jbiosc.2017.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 10/26/2017] [Accepted: 11/01/2017] [Indexed: 02/06/2023]
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16
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Recombinant thermo-alkali-stable endoglucanase of Myceliopthora thermophila BJA (rMt-egl): Biochemical characteristics and applicability in enzymatic saccharification of agro-residues. Int J Biol Macromol 2017; 104:107-116. [DOI: 10.1016/j.ijbiomac.2017.05.167] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 05/13/2017] [Accepted: 05/30/2017] [Indexed: 11/17/2022]
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17
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Chylenski P, Forsberg Z, Ståhlberg J, Várnai A, Lersch M, Bengtsson O, Sæbø S, Horn SJ, Eijsink VGH. Development of minimal enzyme cocktails for hydrolysis of sulfite-pulped lignocellulosic biomass. J Biotechnol 2017; 246:16-23. [PMID: 28219736 DOI: 10.1016/j.jbiotec.2017.02.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 01/26/2017] [Accepted: 02/13/2017] [Indexed: 01/02/2023]
Abstract
Despite recent progress, saccharification of lignocellulosic biomass is still a major cost driver in biorefining. In this study, we present the development of minimal enzyme cocktails for hydrolysis of Norway spruce and sugarcane bagasse, which were pretreated using the so-called BALI™ process, which is based on sulfite pulping technology. Minimal enzyme cocktails were composed using several glycoside hydrolases purified from the industrially relevant filamentous fungus Trichoderma reesei and a purified commercial β-glucosidase from Aspergillus niger. The contribution of in-house expressed lytic polysaccharide monooxygenases (LPMOs) was also tested, since oxidative cleavage of cellulose by such LPMOs is known to be beneficial for conversion efficiency. We show that the optimized cocktails permit efficient saccharification at reasonable enzyme loadings and that the effect of the LPMOs is substrate-dependent. Using a cocktail comprising only four enzymes, glucan conversion for Norway spruce reached >80% at enzyme loadings of 8mg/g glucan, whereas almost 100% conversion was achieved at 16mg/g.
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Affiliation(s)
- Piotr Chylenski
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Zarah Forsberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Jerry Ståhlberg
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anikó Várnai
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | | | | | - Solve Sæbø
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Svein Jarle Horn
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Vincent G H Eijsink
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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Zuorro A, Miglietta S, Familiari G, Lavecchia R. Enhanced lipid recovery from Nannochloropsis microalgae by treatment with optimized cell wall degrading enzyme mixtures. BIORESOURCE TECHNOLOGY 2016; 212:35-41. [PMID: 27078205 DOI: 10.1016/j.biortech.2016.04.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Revised: 04/05/2016] [Accepted: 04/06/2016] [Indexed: 06/05/2023]
Abstract
A statistical mixture design approach was used to investigate the effects of cell wall degrading enzymes on the recovery of lipids from Nannochloropsis sp. A preliminary screening of potentially suitable enzyme preparations, including lysozyme, cellulase and different types of hemicellulases, was carried out. The most effective preparations were then taken as basic components for the formulation of enzyme mixtures. Optimized ternary mixtures consisting of cellulase and two hemicellulases were obtained which allowed the recovery of up to 37.2g of lipids per 100g of dry biomass. SEM and TEM images of the enzymatically treated microalga revealed extensive cell damage, with degradation of the cell wall and release of intracellular material. Overall, the results obtained demonstrate that the mixture design method can be used to prepare cell wall degrading enzyme cocktails that can significantly improve the recovery of lipids or other valuable components from microalgae.
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Affiliation(s)
- Antonio Zuorro
- Department of Chemical Engineering, Materials and Environment, Sapienza University, Roma, Italy
| | - Selenia Miglietta
- Department of Anatomical, Histological, Forensic and Locomotor Apparatus Sciences, Sapienza University, Roma, Italy
| | - Giuseppe Familiari
- Department of Anatomical, Histological, Forensic and Locomotor Apparatus Sciences, Sapienza University, Roma, Italy
| | - Roberto Lavecchia
- Department of Chemical Engineering, Materials and Environment, Sapienza University, Roma, Italy.
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Kemppainen K, Rommi K, Holopainen U, Kruus K. Steam explosion of Brewer’s spent grain improves enzymatic digestibility of carbohydrates and affects solubility and stability of proteins. Appl Biochem Biotechnol 2016; 180:94-108. [DOI: 10.1007/s12010-016-2085-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/11/2016] [Indexed: 11/28/2022]
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Ethanol Production from Enzymatically Treated Dried Food Waste Using Enzymes Produced On-Site. SUSTAINABILITY 2015. [DOI: 10.3390/su7021446] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Wei H, Wang W, Alahuhta M, Vander Wall T, Baker JO, Taylor LE, Decker SR, Himmel ME, Zhang M. Engineering towards a complete heterologous cellulase secretome in Yarrowia lipolytica reveals its potential for consolidated bioprocessing. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:148. [PMID: 25337149 PMCID: PMC4203959 DOI: 10.1186/s13068-014-0148-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 09/24/2014] [Indexed: 05/03/2023]
Abstract
BACKGROUND Yarrowia lipolytica is an oleaginous yeast capable of metabolizing glucose to lipids, which then accumulate intracellularly. However, it lacks the suite of cellulolytic enzymes required to break down biomass cellulose and cannot therefore utilize biomass directly as a carbon source. Toward the development of a direct microbial conversion platform for the production of hydrocarbon fuels from cellulosic biomass, the potential for Y. lipolytica to function as a consolidated bioprocessing strain was investigated by first conducting a genomic search and functional testing of its endogenous glycoside hydrolases. Once the range of endogenous enzymes was determined, the critical cellulases from Trichoderma reesei were cloned into Yarrowia. RESULTS Initially, work to express T. reesei endoglucanase II (EGII) and cellobiohydrolase (CBH) II in Y. lipolytica resulted in the successful secretion of active enzymes. However, a critical cellulase, T. reesei CBHI, while successfully expressed in and secreted from Yarrowia, showed less than expected enzymatic activity, suggesting an incompatibility (probably at the post-translational level) for its expression in Yarrowia. This result prompted us to evaluate alternative or modified CBHI enzymes. Our subsequent expression of a T. reesei-Talaromyces emersonii (Tr-Te) chimeric CBHI, Chaetomium thermophilum CBHI, and Humicola grisea CBHI demonstrated remarkably improved enzymatic activities. Specifically, the purified chimeric Tr-Te CBHI showed a specific activity on Avicel that is comparable to that of the native T. reesei CBHI. Furthermore, the chimeric Tr-Te CBHI also showed significant synergism with EGII and CBHII in degrading cellulosic substrates, using either mixed supernatants or co-cultures of the corresponding Y. lipolytica transformants. The consortia system approach also allows rational volume mixing of the transformant cultures in accordance with the optimal ratio of cellulases required for efficient degradation of cellulosic substrates. CONCLUSIONS Taken together, this work demonstrates the first case of successful expression of a chimeric CBHI with essentially full native activity in Y. lipolytica, and supports the notion that Y. lipolytica strains can be genetically engineered, ultimately by heterologous expression of fungal cellulases and other enzymes, to directly convert lignocellulosic substrates to biofuels.
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Affiliation(s)
- Hui Wei
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Wei Wang
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Markus Alahuhta
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Todd Vander Wall
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - John O Baker
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Larry E Taylor
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Stephen R Decker
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Michael E Himmel
- />Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - Min Zhang
- />National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
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