scholarly journals Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

2014 ◽  
Vol 2014 ◽  
pp. 1-20 ◽  
Author(s):  
H. V. Lee ◽  
S. B. A. Hamid ◽  
S. K. Zain
Keyword(s):  
Molecular Structure ◽  
Mechanical Properties ◽  
Lignocellulosic Biomass ◽  
Chemical Process ◽  
Catalyst Design ◽  
Natural Resistance ◽  
Cellulose Crystallinity ◽  
Biomass Recalcitrance ◽  
Cellulose Accessibility ◽  
High Cellulose

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

scholarly journals Cribellate thread production as model for spider’s spinneret kinematics

2021 ◽  
Author(s):  
Margret Weissbach ◽  
Marius Neugebauer ◽  
Anna-Christin Joel
Keyword(s):  
Molecular Structure ◽  
Mechanical Properties ◽  
Fibre Type ◽  
Material Science ◽  
Spider Silk ◽  
Functional Unit ◽  
Material Strength ◽  
Spinning Process ◽  
Fibre Spinning ◽  
House Spider

AbstractSpider silk attracts researchers from the most diverse fields, such as material science or medicine. However, still little is known about silk aside from its molecular structure and material strength. Spiders produce many different silks and even join several silk types to one functional unit. In cribellate spiders, a complex multi-fibre system with up to six different silks affects the adherence to the prey. The assembly of these cribellate capture threads influences the mechanical properties as each fibre type absorbs forces specifically. For the interplay of fibres, spinnerets have to move spatially and come into contact with each other at specific points in time. However, spinneret kinematics are not well described though highly sophisticated movements are performed which are in no way inferior to the movements of other flexible appendages. We describe here the kinematics for the spinnerets involved in the cribellate spinning process of the grey house spider, Badumna longinqua, as an example of spinneret kinematics in general. With this information, we set a basis for understanding spinneret kinematics in other spinning processes of spiders and additionally provide inspiration for biomimetic multiple fibre spinning.

scholarly journals A comprehensive study of the promoting effect of manganese on white rot fungal treatment for enzymatic hydrolysis of woody and grass lignocellulose

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiao Fu ◽  
Jialong Zhang ◽  
Xiangyu Gu ◽  
Hongbo Yu ◽  
Shulin Chen
Keyword(s):  
Wheat Straw ◽  
Lignocellulosic Biomass ◽  
Quantum Coherence ◽  
Plant Cell Wall ◽  
White Rot ◽  
Yield Enhancement ◽  
Biomass Recalcitrance ◽  
Fungal Treatment ◽  
Ether Linkage ◽  
Glucose Yield

Abstract Background The efficiency of biological systems as an option for pretreating lignocellulosic biomass has to be improved to make the process practical. Fungal treatment with manganese (Mn) addition for improving lignocellulosic biomass fractionation and enzyme accessibility were investigated in this study. The broad-spectrum effect was tested on two different types of feedstocks with three fungal species. Since the physicochemical and structural properties of biomass were the main changes caused by fungal degradation, detailed characterization of biomass structural features was conducted to understand the mechanism of Mn-enhanced biomass saccharification. Results The glucose yields of fungal-treated poplar and wheat straw increased by 2.97- and 5.71-fold, respectively, after Mn addition. Particularly, over 90% of glucose yield was achieved in Mn-assisted Pleurotus ostreatus-treated wheat straw. A comparison study using pyrolysis gas chromatography mass spectrometry (Py-GC/MS) and two-dimensional 1H–13C heteronuclear single quantum coherence (2D HSQC) nuclear magnetic resonance (NMR) spectroscopy was conducted to elucidate the role of Mn addition on fungal disruption of the cross-linked structure of whole plant cell wall. The increased Cα-oxidized products was consistent with the enhanced cleavage of the major β-O-4 ether linkages in poplar and wheat straw lignin or in the wheat straw lignin–carbohydrate complexes (LCCs), which led to the reduced condensation degree in lignin and decreased lignin content in Mn-assisted fungal-treated biomass. The correlation analysis and principal component analysis (PCA) further demonstrated that Mn addition to fungal treatment enhanced bond cleavage in lignin, especially the β-O-4 ether linkage cleavage played the dominant role in removing the biomass recalcitrance and contributing to the glucose yield enhancement. Meanwhile, enhanced deconstruction of LCCs was important in reducing wheat straw recalcitrance. The findings provided not only mechanistic insights into the Mn-enhanced biomass digestibility by fungus, but also a strategy for improving biological pretreatment efficiency of lignocellulose. Conclusion The mechanism of enhanced saccharification of biomass by Mn-assisted fungal treatment mainly through Cα-oxidative cleavage of β-O-4 ether linkages further led to the decreased condensation degree in lignin, as a result, biomass recalcitrance was significantly reduced by Mn addition. Graphic abstract

Devulcanization of Automobile Scrap Tyres by a Mechanochemical Process

2005 ◽  
Vol 21 (4) ◽  
pp. 319-331 ◽  
Author(s):  
G.K. Jana ◽  
C.K. Das
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Chemical Process ◽  
Crosslink Density ◽  
Diallyl Disulfide ◽  
Density Data ◽  
Vulcanized Rubber ◽  
Rubber Waste ◽  
Mechanical Shearing ◽  
Vulcanization Process

The de-vulcanization of rubber waste poses a challenging economical, environmental and social problem. We propose a new de-vulcanization process to re-use the rubber waste. It is a mechano-chemical process (MCP), where the waste is de-vulcanized by a combination of mechanical shearing, heat (110 °C) and the use of a de-vulcanizing agent (diallyl disulfide). A new look at the de-vulcanization mechanism and the influence of the de-vulcanizing agent on the mechanical properties of the ultimate re-vulcanized rubber is also presented. One of the most interesting observations is that the retention of tensile strength of the re-vulcanized rubber with respect to the original tyre was 34.9% when de-vulcanized in the absence of diallyl disulfide and 72.4% in its presence. The formation of extra crosslinks in those re-vulcanized rubbers containing disulfide was confirmed from crosslink density data and from TGA results. DMA analysis revealed that the storage modulus also increased for re-vulcanized rubber containing the disulfide.

Influence of the Molecular Structure and Morphology of Self-Assembled 1,3,5-Benzenetrisamide Nanofibers on their Mechanical Properties

Small ◽  
2012 ◽  
Vol 8 (16) ◽  
pp. 2563-2570 ◽  
Author(s):  
Daniel Kluge ◽  
Julia C. Singer ◽  
Jens W. Neubauer ◽  
Frank Abraham ◽  
Hans-Werner Schmidt ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Mechanical Properties ◽  
Structure And Morphology ◽  
Self Assembled

Inhibition of Maize Caffeate 3-O-Methyltransferase by Nitecapone as a Possible Approach to Reduce Lignocellulosic Biomass Recalcitrance

2020 ◽  
Author(s):  
Angela Valderrama Parizotto ◽  
Ana Paula Ferro ◽  
Rogério Marchiosi ◽  
Aline Finger-Teixeira ◽  
Jennifer Munik Bevilaqua ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Biomass Recalcitrance
Sign in / Sign up

Export Citation Format

Share Document