China
Africa
Explore chapters and articles related to this topic
Nanoparticles Derived from Lignocellulosic Biomass
Published in Megh R. Goyal, Santosh K. Mishra, Lohith Kumar Dasarahalli-Huligowda, Nanotechnology Applications in Agricultural and Bioprocess Engineering, 2021
Lignin mainly comprises of the p-propylphenol polymer that is polymerization of the monolignol forms of lignin [4]. It is a cementing material to provide rigidity to the plant cell-wall and to prevent it from the microbial attack [3, 12]. It is synthesized by the phenylpropanoid biosynthetic pathway. In this process, multi-enzymes are required for the formation of biochemical network of phenyl alanine and tyrosine (grasses), which converts it into the three lignin building blocks, such as: p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. Figure 12.1 shows the extraction of Nanocellulose from lignocellulosic biomass.
Biochemistry
Published in Epstein Eliot, The Science of Composting, 2017
Lignin consists of phenylpropane units represented by coniferyl alcohol (I), p-hydroxycinnanyl alcohol (II) and sinapyl alcohol (III) (Stevenson, 1994). According to Lynch (1993), lignocelluloses, which consist of hemicellulose, cellulose, and lignin, are the principal providers ofthe carbon and energy for microorganisms in the production of compost. Although this may be true for the long-term decomposition of organic materials, during the initial phases of composting the readily available carbon is the important source of carbon.
Mesoporous Adsorbents from Biomass: Opportunities and Challenges in Hydrothermal Treatment
Published in Tushar Kanti Sen, Air, Gas, and Water Pollution Control Using Industrial and Agricultural Solid Wastes Adsorbents, 2017
Akshay Jain, Kubilay Tekin, Madapusi P. Srinivasan
Carbonized biomass (e.g., hydrochars, activated carbons, carbon nanotubes, graphene) are generating great interest in a wide range of applications in filtration and separation technology, energy storage, batteries, catalysis, sensor, environmental remediation, and bioapplications (Dawood, Sen, and Phan 2014; Jain, Balasubramanian, and Srinivasan 2015b; Luo et al. 2014; Sen, Afroze, and Ang 2011; Wei et al. 2016; Xie et al. 2015; Xu et al. 2015; Yang et al. 2016). These diverse applications arise from the remarkable and unique properties of carbon in biomass, such as bonding ability, chemical stability, thermal and electrical conductivity, high porosity, and tunable surface chemistry (Thompson et al. 2015). Biomass content varies according to the type of the biomass, and plays a crucial role in the utilization process. The category of lignocellulosic biomass primarily comprises cellulose, hemicellulose, and lignin. A complex carbohydrate, cellulose is represented by the general formula (C6H10O5)n with molecular masses ranging up to 500,000 u (Figure 11.1). It is a crystalline natural polymer formed by the β-1,4 glycosidic linkage of D-glucopyranose monomers. It is an important raw material due to its abundance, high energy content, and exclusive properties, such as strength, insolubility, and biodegradable structure (Klemm et al. 2005; Kobayashi and Makino 2009). Hemicellulose is an amorphous carbohydrate composed mainly of D-glucopyranose, D-xylopyranose, D-galactopyranose, D-mannopyranose, and L-arabinofuranose units with a lower degree of polymerization than cellulose. Unlike cellulose, hemicellulose has a branched structure and due to its relatively low degree of polymerization and amorphous structure, hemicellulose can be easily degraded to its constituent components. It is soluble both in acidic (2% HCl) and alkaline (5% Na2CO3) solutions, and forms a viscous state or becomes a gelling agent in water depending on the concentration (Chen 2014). Lignin, the third component of lignocellulosic biomass, comprises methoxylated phenylpropane units and has amorphous, highly branched structure with very low solubility in water. p-Coumaryl alcohol (4-[(E)-3-hydroxyprop-1-enyl]phenol), coniferyl alcohol (4-(3-hydroxy-1-propenyl)-2-methoxyphenol), and sinapyl alcohol (4-(3-hydroxyprop-1-enyl)-2,6-dimethoxyphenol) are the three basic monomers of lignin (Liu, Jiang, and Yu 2015). It is produced in large quantities as a waste of the paper-making process (isolation of cellulose) and in the bioethanol production from lignocellulosic biomass (Deepa and Dhepe 2014). It can be combusted to produce heat and power in industries as a low-grade fuel, but, if depolymerized effectively, it is a valuable source of commercially important chemicals, fuel, or fuel additives. Thermochemical conversion of lignin also allows producing of functional carbon materials with various applications in the removal of pollutants, energy storage, and catalysis (Liu, Jiang, and Yu 2015).
Biobased polymers from lignocellulosic sources
Published in Green Chemistry Letters and Reviews, 2023
Rachele N. Carafa, Daniel A. Foucher, Guerino G. Sacripante
Lignin is a complex aromatic macromolecule that accounts for roughly 15-20 wt% of the lignocellulose and contains a non-crystalline and irregular 3-D structure held together by ether and carbon–carbon linkages, although the former is the dominant linkage for regular lignin (25). Lignin is derived from three phenylpropanoid monomer units or monolignols, which are p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol (Figure 6). These can be further broken down to form the base aromatic ring structures containing p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) subunits in the polymer, which consist of one phenol group, one phenol and one methoxy group, and one phenol and two methoxy groups, respectively (28). Lignin composition differs depending on the biomass source, where softwood lignin typically contains more G units and hardwood lignin has more S units. These differences in the overall composition have an affect on its reactivity, though it contributes to the structural strength and stiffness of the cell wall (1,25).
Comprehensive depolymerization of lignin from lignocellulosic biomass: A review
Published in Critical Reviews in Environmental Science and Technology, 2023
Qinghua Ji, Xiaojie Yu, Li Chen, Abdullateef Taiye Mustapha, Clinton Emeka Okonkwo, Cunshan Zhou, Xianming Liu
Lignin is a natural phenolic polymer that is highly abundant in the world. Lignin polymers usually form ether and ester bonds with hemicellulose, and hemicellulose binds to cellulose, which makes the lignocellulosic structure more complex (Figure S2). Lignin is composed of complex lignin monomers or phenylpropane, namely sinapyl alcohol, coniferyl alcohol, and p-coumarin, which are referred to as syringyl, guaiacyl, and p-hydroxyphenyl, respectively. The monomers in lignin are connected to each other by primary chemical bonds, such as aryl ether or alkyl ether, C–C, and ester (Figure 1). Therefore, efficient conversion of renewable lignin into value-added chemicals and biofuel is of great importance for the sustainable development of biorefineries (Cao et al., 2021).