scholarly journals Biochemical, structural insights of newly isolated AA16 family of Lytic Polysaccharide Monooxygenase (LPMO) from Aspergillus fumigatus and investigation of its synergistic effect using biomass.

2020 ◽  
Author(s):  
Musaddique Hossain ◽  
Subba Reddy Dodda ◽  
Bishwajit Singh Kapoor ◽  
Kaustav Aikat ◽  
sudit mukhopadhyay
Keyword(s):  
Aspergillus Fumigatus ◽  
Lignocellulosic Biomass ◽  
Three Dimensional ◽  
Cellulose Hydrolysis ◽  
Inducible Promoter ◽  
Dimensional Structure ◽  
Biomass Hydrolysis ◽  
Lytic Polysaccharide Monooxygenase ◽  
Intronless Gene ◽  
Polysaccharide Monooxygenase

The efficient conversion of lignocellulosic biomass into fermentable sugar is a bottleneck for the cheap production of bio-ethanol. The recently identified enzyme Lytic Polysaccharide Monooxygenase (LPMO) family has brought new hope because of its boosting capabilities of cellulose hydrolysis. In this report, we have identified and characterized a new class of auxiliary (AA16) oxidative enzyme LPMO from the genome of a locally isolated thermophilic fungus Aspergillus fumigatus (NITDGPKA3) and evaluated its boosting capacity of biomass hydrolysis. The AfLPMO16 is an intronless gene and encodes the 29kDa protein. While Sequence-wise, it is close to the C1 type of AaAA16 and cellulose-active AA10 family of LPMOs, but the predicted three-dimensional structure shows the resemblance with the AA11 family of LPMO (PDB Id: 4MAH). The gene was expressed under an inducible promoter (AOX1) with C-terminal His tag in the Pichia pastoris. The protein was purified using Ni-NTA affinity chromatography, and we studied the enzyme kinetics with 2,6-dimethoxyphenol. We observed polysaccharides depolymerization activity with Carboxymethyl cellulose (CMC) and Phosphoric acid swollen cellulose (PASC). Moreover, the simultaneous use of cellulase cocktail (commercial) and AfLPMO16 enhances lignocellulosic biomass hydrolysis by 2-fold, which is highest so far reported in the LPMO family.

scholarly journals LPMO AfAA9_B and Cellobiohydrolase AfCel6A from A. fumigatus Boost Enzymatic Saccharification Activity of Cellulase Cocktail

2020 ◽  
Vol 22 (1) ◽  
pp. 276
Author(s):  
Aline Vianna Bernardi ◽  
Luis Eduardo Gerolamo ◽  
Paula Fagundes de Gouvêa ◽  
Deborah Kimie Yonamine ◽  
Lucas Matheus Soares Pereira ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Aspergillus Fumigatus ◽  
Lignocellulosic Biomass ◽  
Biochemical Parameters ◽  
Enzymatic Saccharification ◽  
Fermentable Sugars ◽  
Optimal Temperature ◽  
High Turnover ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

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.

scholarly journals Characterization of a lytic polysaccharide monooxygenase from Aspergillus fumigatus shows functional variation among family AA11 fungal LPMOs

2021 ◽  
pp. 101421
Author(s):  
Fredrik Gjerstad Støpamo ◽  
Åsmund Kjendseth Røhr ◽  
Sophanit Mekasha ◽  
Dejan M. Petrović ◽  
Anikó Várnai ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Functional Variation ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

scholarly journals LPMO AfAA9_B and Cellobiohydrolase AfCel6A from A. fumigatus Bost Enzymatic Saccharification Activity of Cellulase Cocktail

2020 ◽  
Author(s):  
Taisa Magnani Dinamarco ◽  
Aline Vianna Bernardi ◽  
Luis Eduardo Gerolamo ◽  
Paula Fagundes de Gouvêa ◽  
Deborah Kimie Yonamine ◽  
...  
Keyword(s):  
Pichia Pastoris ◽  
Lignocellulosic Biomass ◽  
Filamentous Fungi ◽  
Biochemical Parameters ◽  
Enzymatic Saccharification ◽  
Fermentable Sugars ◽  
Optimal Temperature ◽  
High Turnover ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

Cellulose is the most abundant polysaccharide in lignocellulosic biomass, where it is interlinked with lignin and hemicellulose. Bioethanol can be produced from biomass. Because 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 A. 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. Association of AfCel6A and AfAA9_B inhibits the activity of AfCel6A, an outcome that needs to be further investigated. However, addition of AfCel6A or AfAA9_B boosts the enzymatic saccharification activity of a cellulase cocktail and the activity of cellulase Af-EGL7. The supplementation of an enzymatic cocktail 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 is enzyme- and substrate-specific, which suggests a specific enzymatic cocktail for each biomass.

scholarly journals A Thermostable Aspergillus fumigatus GH7 Endoglucanase Over-Expressed in Pichia pastoris Stimulates Lignocellulosic Biomass Hydrolysis

2019 ◽  
Vol 20 (9) ◽  
pp. 2261 ◽  
Author(s):  
Aline Vianna Bernardi ◽  
Deborah Kimie Yonamine ◽  
Sergio Akira Uyemura ◽  
Taisa Magnani Dinamarco
Keyword(s):  
Pichia Pastoris ◽  
Aspergillus Fumigatus ◽  
Lignocellulosic Biomass ◽  
Renewable Energy Sources ◽  
Industrial Applications ◽  
The Novel ◽  
Biomass Hydrolysis ◽  
Ph Range ◽  
Hydrolysis Of

In the context of avoiding the use of non-renewable energy sources, employing lignocellulosic biomass for ethanol production remains a challenge. Cellulases play an important role in this scenario: they are some of the most important industrial enzymes that can hydrolyze lignocellulose. This study aims to improve on the characterization of a thermostable Aspergillus fumigatus endo-1,4-β-glucanase GH7 (Af-EGL7). To this end, Af-EGL7 was successfully expressed in Pichia pastoris X-33. The kinetic parameters Km and Vmax were estimated and suggested a robust enzyme. The recombinant protein was highly stable within an extreme pH range (3.0–8.0) and was highly thermostable at 55 °C for 72 h. Low Cu2+ concentrations (0.1–1.0 mM) stimulated Af-EGL7 activity up to 117%. Af-EGL7 was tolerant to inhibition by products, such as glucose and cellobiose. Glucose at 50 mM did not inhibit Af-EGL7 activity, whereas 50 mM cellobiose inhibited Af-EGL7 activity by just 35%. Additionally, the Celluclast® 1.5L cocktail supplemented with Af-EGL7 provided improved hydrolysis of sugarcane bagasse “in natura”, sugarcane exploded bagasse (SEB), corncob, rice straw, and bean straw. In conclusion, the novel characterization of Af-EGL7 conducted in this study highlights the extraordinary properties that make Af-EGL7 a promising candidate for industrial applications.

Structure of a lytic polysaccharide monooxygenase from Aspergillus fumigatus and an engineered thermostable variant

2018 ◽  
Vol 469 ◽  
pp. 55-59 ◽  
Author(s):  
Leila Lo Leggio ◽  
Cecilia D. Weihe ◽  
Jens-Christian N. Poulsen ◽  
Matt Sweeney ◽  
Frank Rasmussen ◽  
...  
Keyword(s):  
Aspergillus Fumigatus ◽  
Lytic Polysaccharide Monooxygenase ◽  
Polysaccharide Monooxygenase

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

1977 ◽  
Vol 35 ◽  
pp. 562-563
Author(s):  
Robert Glaeser ◽  
Thomas Bauer ◽  
David Grano
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
Serial Sections ◽  
Thin Sections ◽  
3 Dimensional ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Dimensional Reconstruction ◽  
Stereo Imagery ◽  
Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

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