scholarly journals Stochastic model of lignocellulosic material saccharification

2021 ◽  
Vol 17 (9) ◽  
pp. e1009262
Author(s):  
Eric Behle ◽  
Adélaïde Raguin
Keyword(s):  
Lignin Content ◽  
Three Dimensional ◽  
Enzymatic Saccharification ◽  
Biofuel Production ◽  
Dimensional Structure ◽  
Gillespie Algorithm ◽  
Promising Alternative ◽  
Fitting Procedure ◽  
Time Courses ◽  
Pre Treatment

The processing of agricultural wastes towards extraction of renewable resources is recently being considered as a promising alternative to conventional biofuel production. The degradation of agricultural residues is a complex chemical process that is currently time intensive and costly. Various pre-treatment methods are being investigated to determine the subsequent modification of the material and the main obstacles in increasing the enzymatic saccharification. In this study, we present a computational model that complements the experimental approaches. We decipher how the three-dimensional structure of the substrate impacts the saccharification dynamics. We model a cell wall microfibril composed of cellulose and surrounded by hemicellulose and lignin, with various relative abundances and arrangements. This substrate is subjected to digestion by different cocktails of well characterized enzymes. The saccharification dynamics is simulated in silico using a stochastic procedure based on a Gillespie algorithm. As we additionally implement a fitting procedure that optimizes the parameters of the simulation runs, we are able to reproduce experimental saccharification time courses for corn stover. Our model highlights the synergistic action of enzymes, and confirms the linear decrease of sugar conversion when either lignin content or crystallinity of the substrate increases. Importantly, we show that considering the crystallinity of cellulose in addition to the substrate composition is essential to interpret experimental saccharification data. Finally, our findings support the hypothesis of xylan being partially crystalline.

Liquid chromatography mass spectrometry based characterization of epitope configurations

2020 ◽  
Vol 12 (45) ◽  
pp. 5476-5484
Author(s):  
Maren Christin Stillesby Levernæs ◽  
Arelí Urtubia Moe ◽  
Sigurd Leinæs Bøe ◽  
Elisabeth Paus ◽  
Léon Reubsaet ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Liquid Chromatography Mass Spectrometry ◽  
Three Dimensional Structure ◽  
Chromatography Mass Spectrometry ◽  
Pre Treatment

Here we evaluate a quick and easy tool for determination of epitope configuration using immunocapture and liquid chromatography mass spectrometry (LC-MS) subsequent to pre-treatment of the target protein to disrupt its three-dimensional structure.

Catalysed-microwave based Pretreatment of Lignocellulosic Biomass of Camelina Sativa L. for Bio-Fuel Production

2017 ◽  
Vol 3 (1) ◽  
pp. 59 ◽  
Author(s):  
Sanjay Mohan Gupta ◽  
Kamal Kumar ◽  
Rakshit Pathak ◽  
Sanjai Kumar Dwivedi
Keyword(s):  
Lignocellulosic Biomass ◽  
Lignin Content ◽  
Soluble Sugars ◽  
Good Alternative ◽  
Camelina Sativa ◽  
Cellulosic Biomass ◽  
Fuel Production ◽  
Glucose Content ◽  
Promising Alternative ◽  
Pre Treatment

<p>Lignocellulosic biomasses are promising alternative resource for bio-fuel production. But due to the recalcitrant nature of lignin and hemicellulose, necessitates an efficient pre-treatment process to improve the yield of reducing sugars and maximising the enzymatic hydrolysis efficiency. Catalysed-microwave pre-treatment may be a good alternative as compared to other methods since it can reduce the time and improve the enzymatic activity during hydrolysis. The aim of this study was to evaluate the efficiency of the catalysed-microwave based pre-treatment of lignocellulosic biomass of Camelina sativa straw (CSS) to overcome the recalcitrant nature of cellulosic biomass. The microwave-alkaline (2 % NaOH) pre-treatment of CSS at 250 W for 10 min yields maximum (~422 mg/g) total soluble sugars (TSS) production during hydrolysis. Likewise, the maximum glucose content (~294 mg/g) was measured in 2 % alkaline-microwave pre-treatment for 10 min at RT. However, slight increase in lignin degradation was observed with the increase in alkaline hydroxide concentration and microwave irradiation exposure time. The maximum degradation in lignin content (~83 %) was measured in 3 % alkaline-microwave pre-treatment for 20 min at RT. Our results suggest that the microwave-alkaline pre-treatment approach may be employed for comprehensive utilisation of CSS biomass of Camelina sativa L. cv. Calena (EC643910) for bio-fuel production.</p>

scholarly journals The three-dimensional structure of the cellobiohydrolase Cel7A fromAspergillus fumigatusat 1.5 Å resolution

2015 ◽  
Vol 71 (1) ◽  
pp. 114-120 ◽  
Author(s):  
Olga V. Moroz ◽  
Michelle Maranta ◽  
Tarana Shaghasi ◽  
Paul V. Harris ◽  
Keith S. Wilson ◽  
...  
Keyword(s):  
Enzymatic Degradation ◽  
Plant Cell Wall ◽  
Three Dimensional ◽  
Biofuel Production ◽  
Industrial Processes ◽  
Dimensional Structure ◽  
Carbohydrate Active Enzymes ◽  
Cazy Database ◽  
Generation Biofuel ◽  
Insight Into

The enzymatic degradation of plant cell-wall cellulose is central to many industrial processes, including second-generation biofuel production. Key players in this deconstruction are the fungal cellobiohydrolases (CBHs), notably those from family GH7 of the carbohydrate-active enzymes (CAZY) database, which are generally known as CBHI enzymes. Here, three-dimensional structures are reported of theAspergillus fumigatusCBHI Cel7A solved in uncomplexed and disaccharide-bound forms at resolutions of 1.8 and 1.5 Å, respectively. The product complex with a disaccharide in the +1 and +2 subsites adds to the growing three-dimensional insight into this family of industrially relevant biocatalysts.

scholarly journals Structure, kinematics, and ages of the young stellar populations in the Orion region

2019 ◽  
Vol 628 ◽  
pp. A123 ◽  
Author(s):  
E. Zari ◽  
A. G. A. Brown ◽  
P. T. de Zeeuw
Keyword(s):  
Star Formation ◽  
Clustering Algorithm ◽  
Age Distribution ◽  
Three Dimensional ◽  
Star Formation History ◽  
Dimensional Structure ◽  
Mean Velocity ◽  
Fitting Procedure ◽  
Sequence Of Events ◽  
Kinematic Modelling

We present a study of the three dimensional structure, kinematics, and age distribution of the Orion OB association, based on the second data release of the Gaia satellite (Gaia DR2). Our goal is to obtain a complete picture of the star formation history of the Orion complex and to relate our findings to theories of sequential and triggered star formation. We selected the Orion population with simple photometric criteria, and we constructed a three dimensional map in galactic Cartesian co-ordinates to study the physical arrangement of the stellar clusters in the Orion region. The map shows structures that extend for roughly 150 pc along the line of sight, divided in multiple sub-clusters. We separated different groups by using the density-based clustering algorithm DBSCAN. We studied the kinematic properties of all the groups found by DBSCAN first by inspecting their proper motion distribution, and then by applying a kinematic modelling code based on an iterative maximum likelihood approach, which we used to derive their mean velocity, velocity dispersion, and isotropic expansion. We derived ages and extinction values for all the groups by using an isochrone fitting procedure. We confirm the presence of an old population (∼15 Myr) towards the 25 Ori region, and we find that groups with ages of 12 − 15 Myr are present also towards the Belt region. We notice the presence of a population of ∼10 Myr also in front of the Orion A molecular cloud. Our findings suggest that star formation in Orion does not follow a simple sequential scenario, but instead consists of multiple events, which caused kinematic and physical sub-structure. To fully explain the detailed sequence of events, specific simulations and further radial velocity data are needed.

scholarly journals Effect of Dilute Acid and Alkaline Pretreatments on Enzymatic Saccharfication of Palm Tree Trunk Waste for Bioethanol Production

2019 ◽  
Vol 14 (3) ◽  
pp. 705 ◽  
Author(s):  
Kusmiyati Kusmiyati ◽  
Sakina Tunissa Anarki ◽  
Sabda Wahyu Nugroho ◽  
Reistu Widiastutik ◽  
Hadiyanto Hadiyanto
Keyword(s):  
Substrate Concentration ◽  
Lignin Content ◽  
Enzymatic Saccharification ◽  
Reducing Sugar ◽  
Total Sugar ◽  
Steam Pretreatment ◽  
Palm Tree ◽  
Bioethanol Production ◽  
Tree Trunk ◽  
Pre Treatment

The sugar palm tree (Arenga pinnata) was abundant in Indonesia and has high cellulose contents for bioethanol production. However, the lignin content was the major drawback which could inhibit saccharification enzymes and therefore removing the lignin from the biomass is important. This paper evaluated the effects of pretreatments  using nitric acid (HNO3) and ammonium hydroxide (NH4OH) at 2 to 10% (v/v) on reducing sugar and ethanol contents and compared with the effects of steam pre-treatment. The pretreated samples were hydrolyzed using cellulase enzymes at pH 5.0 with a substrate concentration of 10% (w/v) for 24 to 72 h at 50 °C. Subsequent assessments of enzymatic saccharification following pre-treatment with 10% (v/v) HNO3 showed maximum reducing   and total sugar contents in palm tree trunk waste of 5.320% and 5.834%, respectively, after 72 h of saccharification. Following pretreatment with 10% (v/v) of NH4OH, the maximum reducing and total sugar contents of palm tree trunk waste were 2.892% and 3.556%, respectively, after 72 h of saccharification. In comparison, steam pretreatments gave maximum reducing sugar and total sugar contents of 1.140% and 1.315% under the same conditions. Simultaneous saccharification and fermentation (SSF) was conducted at 37 °C (pH 4.8) and 100 rpm for 120 h using 10% (v/v) Saccharomyces cerevisiae and cellulase enzyme with a substrate concentration of 10% (w/v). The result showed the highest ethanol content of 2.648% was achieved by using 10% (v/v) HNO3. The use of 10% (v/v) NH4OH gained a yield of 0.869% ethanol while the steam pretreatment could obtained 0.102% ethanol.  Copyright © 2019 BCREC Group. All rights reserved 

scholarly journals Potentials of Acremonium butyri fungus in pre-treatment and hydrolysis using Rice husk substrate for biofuel production: A short communication

2020 ◽  
pp. 131-137
Author(s):  
Sanusi A. ◽  
Keyword(s):  
Rice Husk ◽  
Room Temperature ◽  
Lignin Content ◽  
Fungal Growth ◽  
Reducing Sugar ◽  
Biofuel Production ◽  
Moist Environment ◽  
The Difference ◽  
Pre Treatment ◽  
Over Exploitation

There is increasing interest in the area of biofuel production due to fear of fossil fuel extinction as a result of over exploitation and crises. During biofuel production, substrate needs to undergo pre-treatment and hydrolysis where acids and alkali are mostly used. In this study, Acremonium butyri was used for both pre-treatment and hydrolysis. Structural compositions of the rice husk were determined. Extractives, hemicellulose and Lignin content was determined via extraction using Soxhlet extractor while cellulose was determined as the difference from the extractives, hemicelluloses and lignin. Acremonium butyri was isolated from dried roots of Piliostigma reticulatum (Kalgo) by keeping the roots in a clean plastic for a period of 7 days on moist environment after which fungal growth appeared. The growth was aseptically transferred on to prepared S.D.A plate and kept at room temperature. The fungal growth was identified as based on the physical and microscopic characteristics. About 50g of rice husk was mixed with 500 ml of distilled water in the ration of 1:10 to obtain homogenous slurry and then inoculated with 2ml of prepared Acremonium butyri solution and incubated at room temperature for up to 3 weeks with frequent shaking at certain intervals. Reducing sugar test was carried out to determine the reducing sugar released with UV-VIS spectrophotometer. The results obtained indicate that rice husk contained 32%, 30%, 29% and 8.4% of cellulose, hemicelluloses, extractives and lignin respectively. And a total of 0.936g/l of reducing sugar was released after 3 weeks of pre-treatment. The results implies that Acremonium butyri separated the component of rice husk (pre-treatment) as well as break down cellulose and hemicelluloses into its monomers (hydrolysis) thereby releasing sugar. Hence, Acremonium butyri is a good microorganism for biological pre-tretment and hydrolysis. Keywords: Acremonium butyri, Rice Husk, Pre-treatment, Hydrolysis, Biofuel

scholarly journals Assessment of Durum Wheat (Triticum durum Desf.) Genotypes Diversity for the Integrated Production of Bioethanol and Grains

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7735
Author(s):  
Donatella Danzi ◽  
Ivana Marino ◽  
Isabella De Bari ◽  
Silvio Mastrolitti ◽  
Giacomo L. Petretto ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Wheat Straw ◽  
Structural Integrity ◽  
Lignin Content ◽  
Complex Structure ◽  
Three Dimensional ◽  
Germplasm Collection ◽  
Biofuel Production ◽  
Fermentable Sugars ◽  
Uronic Acids

Wheat straw is an abundant source of lignocellulosic biomass that is generally not utilized for biofuel production, nor for other uses. Recent EU renewable energy directive fosters bioethanol production through lignocellulosic sugars fermentation, but the cost of this process is an issue that often depends on biomass characteristics. Lignin is a class of three-dimensional polymers providing structural integrity of plant tissues. Its complex structure, together with hemicelluloses and uronic acids content, could affect the ability of hydrolyzing biomass to fermentable sugars. To get insights into this variation, a set of 10 durum wheat genotypes was analyzed to determine variation of straw digestibility to fermentable sugars. The results showed that the lignin content was the major factor determining the recalcitrance to enzymatic process. The analysis of Spearman’s correlation indicated that the sugar released after enzymatic hydrolysis had a negative connection with the lignin content, while it was positively correlated with the culm length. The possible role of other cell wall components, such as arabinose and uronic acids, was also discussed. This work aimed at analyzing the diversity of lignocellulosic digestibility to fermentable sugars of wheat straw in a small germplasm collection. Some of the selected genotypes were characterized by high sugars digestibility and high grain yield, characteristics that could make biorefining of wheat straw profitable.

scholarly journals Fiber fines for fabricating lignocellulose films and the effect of lignin

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 4417-4433
Author(s):  
Mohammad Pourjafar ◽  
Amir Khosravani ◽  
Rabi Behrooz
Keyword(s):  
Lignin Content ◽  
Three Dimensional ◽  
Strength Properties ◽  
Degree Of Polymerization ◽  
Dimensional Structure ◽  
Film Properties ◽  
Imidazolium Chloride ◽  
Low Degree ◽  
Rapid Dissolution ◽  
Fiber Processing

Excess lignocellulose fines in some fiber processing mills cause issues and hurt product quality. To use this type of biomaterial as a resource, surplus fines can be separated and dissolved with solvents for further transformation. Therefore, 1-butyl 3-methyl imidazolium chloride ionic liquid (IL) was used as a powerful green solvent for a rapid dissolution process. However, a low degree of polymerization (DP) of the cellulose in fines and the effects of lignin content and its structure on the process and film properties are controversial subjects. This study demonstrated that the three dimensional structure of lignin did not permit the raw bagasse fines (prior to pulping) to dissolve in the IL even after several hours. However, following decomposition of the lignin structure by pulping, the fiber fines were readily dissolved. Further, all the fabricated films from the fiber fines exhibited satisfactory strength properties, despite the fact that the cellulose had a low DP. The films from bleached fiber fines showed higher tensile strength than those containing lignin, although the cellulose chain was longer and had a higher DP for the latter. Lignin resulted in reduced transparency, and higher absorption of ultraviolet radiations, but it did not affect the surface roughness of the films.

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.

Sign in / Sign up

Export Citation Format

Share Document