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Lignin is considered by many as the ultimate barrier that impedes biomass conversion to fuels and chemicals. Several delignification strategies have been developed so far, but alkaline extraction remains the most widely used. However, this technology has a high chemical demand, consumes large amounts of water, and generates effluents that are hard to handle. Organosolv pulping is a good option for such application, but the impact of solvent losses and harmful emissions may be unsustainable. To this end, the use of greener alternatives such as water, biobased solvents, ionic liquids, and deep eutectic solvents, under sub- or supercritical conditions, may pave the road for the development of sustainable biorefineries.

This work physically, mechanically, and chemically characterized the composites produced from Portland CP II-E32 cement and fresh Indian cedar wood particles previously treated by immersion in hot and cold water. Density values for wood particulate composites were around 50% lower compared with the wood-free control treatment, from 0.88 to 1.78 g/cm³. A larger swelling was observed for the composite material. The results of compressive strength and stiffness indicated that there is no need for particle treatment for composite production. Hot and cold water immersion treatments reduced the total Indian cedar wood extractives by 33% and 42%, respectively. Optical microscopy analysis was used to identify adhesion failures between the cement/wood interface of the composite produced with fresh particles, which presented a higher percentage of extractives. This result indicated that the greater concentration of total extractives partially inhibits the matrix-matrix interaction reinforcement. Despite the reduction in total extractives caused by the treatments, this process is not necessary for the composite production because there is no statistical difference between the treatments. The values obtained for the composite indicate the possibility of application in sealing blocks in light construction systems. [ABSTRACT FROM AUTHOR]

As an important sustainable source of biomass, lignocellulosic materials are highly recalcitrant to biotransformation, which limits their use and prevents economically viable conversion into value-added products. Ionic liquids (ILs) have emerged as attractive solvents for lignocellulosic biomass pretreatment in the production of biochemical feedstocks. In this work, a mixture of wood powder and waste paper was dissolved in the ionic liquid 1-allyl-3-methylimidazolium chloride ([AMIM]Cl). Composite films were made from the regenerated lignocellulosic materials in [AMIM]Cl by adjusting the ratio of the raw materials. The physical and mechanical properties of biomass composite films were determined by optical microscopy (OM), Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), and tensile strength tests. The results indicated that lignocellulosic materials were dissolved in [AMIM]Cl by destroying interand intramolecular hydrogen bonds between lignocelluloses. With increasing waste paper cellulose content, the dissolution of the fir powder in [AMIM]Cl was accelerated, and the tensile strength and elongation at break of the composite films increased. The rate of dissolution initially rose rapidly with increasing content of waste paper cellulose content, but the rate leveled off when the content was above 40%. This research highlights new opportunities for biodegradable composite films made from waste biomass. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass resources are renewable materials that can be converted to fermentable sugars and subsequently into ethanol. Water hyacinth (Eichhornia crassipes) is a cellulosic aquatic plant that has high carbohydrates, low lignin content, and notable reducing sugars content in its structure. Based on the literature review in the case of water hyacinth, the most frequently used pretreatment methods were acid and alkali, while ionic liquid and microwave-assisted methods were used rarely. The dominant sugars were glucose, xylose, galactose, arabinose, and mannose. Based on the findings, cellulase and S. cerevisiae were mostly used for enzymatic hydrolysis and fermentation of water hyacinth to ethanol, respectively. This review presents the recent studies in pretreatment, hydrolysis, and fermentation of water hyacinth biomass into ethanol.

As the worldwide demand for fuels and materials increases, fossil resources are decreasing and global warming is a concern, and thus the need for alternative solutions is high. In the industries of furniture and housing, particleboards are interesting materials, as they reutilize wastes from other industries (wood, agriculture) although they also rely on chemical binders that are petroleum-based and toxic. A very promising alternative is then clearly identified in finding ways to produce binderless boards and associated materials. This review considers the state of the art in the field of binderless board production, and other processes making it possible to turn raw plant fibers into structural materials without using any external chemistry. The mechanical properties and water resistance are collected and compared. Identified chemistry changes occurring during the thermo-compressive process are discussed with an aim towards understanding of the mechanisms of cohesion.

A characterization study on oil palm decanter cakes (OPDC) was performed to gain an in-depth understanding of the material’s characteristics to aid in potential residual oil recovery. The OPDC was characterized by a high moisture content, high biodegradability, high organic content, and a nutrient-rich composition. Microscopic observation showed that the oil attachments in OPDC, and a vast majority of the droplets, were less than 50 μm in size. Furthermore, contact angle measurement revealed the hydrophilic and oleophilic characteristics of OPDC. Specifically, the contact angles of water and crude palm oil (CPO) with OPDC were both less than 45° with absorption rates of 0.0265  0.003 µL/s and 0.1042  0.05 µL/s, respectively. The OPDC is a fibrous material, and the surface area and pore size measured were 7.103 m2/g and 481.7 Å, respectively. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis results showed the functional groups and degradation properties of OPDC, respectively.

Agro-industrial wastes are the most abundant renewable resource on earth and are available in large quantities. However, the disposal of these wastes presents an increasing environmental problem. Recently, there has been a great interest in the exploitation of these wastes as low-cost raw materials for the production of value-added compounds as microbial enzymes by submerged or solid-state fermentation systems. This review focuses on alternatives for xylanase production using agro-residues as substrates. In recent years, the interest in xylanase, which plays an important role in the breakdown of xylan, has markedly increased due to its wide variety of biotechnological applications. Among several agro-industrial residues that have been intensively investigated, many, such as wheat bran, wheat straw, and sugarcane bagasse, are suitable and result in high yields of xylanase, leading to low production costs. In addition, many relatively unexplored residues, such as oil palm wastes, sorghum straw, and coffee by-products, are some of the most promising substrates for xylanase production, requiring further assessment.

High-pressure steam treatment (HPST) is a potential alternative method for the modification of lignocellulosic materials. The effect of HPST on oil palm mesocarp fibers (OPMF) was successfully investigated with treatment conditions of 170 ºC/ 0.82 MPa, 190 ºC/ 1.32 MPa, 210 ºC/ 2.03 MPa, and 230 ºC/ 3.00 MPa for 2 min. treatment time. Significant changes in the colour, smell, and mechanical properties of the samples were observed after the treatment. Scanning electron microscope (SEM) images revealed changes in the surface morphology of the OPMF after the pretreatment. The degradation of hemicelluloses and changes in the functional groups of the lignocellulosic components were identified using Fourier Transform Infrared (FTIR) and Thermogravimetric (TG) analysis. These results suggest that HPST is a promising method for the pretreatment of OPMF.

Considering the mild degradation strength and the fact that it may be an organic matter reserve for the soil, in the past years lignocellulosic materials have been used as fibrous raw materials in the manufacture of biodegradable nutritive pots for the seedling in vegetable containerized production. This paper analyses the behavior of the nutritive pots made from biodegradable composites for the vegetable seedling production process, focusing on their mechanical strength properties and biodegradability. It was found that the biodegradability of composite materials obtained from a mixture of secondary cellulosic fibers, peat, and additives, is strongly influenced by the presence or absence of the rhizosphere effect and the synergistic relations set in the culture substrate between the plant roots and microorganisms, which develop permanently the recycling and solubilization of mineral nutrients. The results showed that the presence in the substrate of some complex populations made by heterotrophic bacteria favors full degradation of the pulp and lignin contained in the substrate and pots composition. Therefore, unlike the reference sample (plant-free), cultivated versions exhibited an intense biodegradation on the account of rhizosphere effect.

In order to prepare nanoparticles, corn cobs were treated with sodium hydroxide in the range 0-6 mole/litre (0-24% of sodium hydroxide on oven dry basis) at 165 oC for 1.5 h at a liquor to solid ratio of 4.5:1. The sample obtained at the optimised condition (4.5 mole/litre) was washed with deionised water, disintegrated, and filtered through 80 mesh screens. Powder thus obtained was delignified by acidified sodium chlorite and dried in a vacuum oven to constant weight. Dried powder was further separated by 270 mesh screens. An average particle size approximately equal to 22 nm was observed by Transmission Electron Microscopy (TEM). Its crystallinity was determined by XRD analysis. The aggregated particle size was observed in the micron range by Scanning Electron Microscopy (SEM).

Lignocellulosic materials such as agricultural residues have been recog-nized as potential sustainable sources of mixed sugars for fermentation to bioethanol. To obtain a high overall ethanol yield and achieve an economically feasible production process, the removal of lignin and hemicelluloses improves the accessibility of cellulosic material to hydro-lytic enzymes and avoids the degradation products that are inhibitory to the yeast used in the subsequent fermentation. Technological advances, e.g., environmentally friendly removal of lignin and hemicelluloses from lignocellulosic biomass prior to fermentation of the librated glucose from cellulose into bioethanol, has the potential to provide for sustainable and cost effective production of biofuel.

This article reviews developments in the technology for ethanol produc-tion from lignocellulosic materials by “enzymatic” processes. Several methods of pretreatment of lignocelluloses are discussed, where the crystalline structure of lignocelluloses is opened up, making them more accessible to the cellulase enzymes. The characteristics of these enzymes and important factors in enzymatic hydrolysis of the cellulose and hemicellulose to cellobiose, glucose, and other sugars are discussed. Different strategies are then described for enzymatic hydrolysis and fermentation, including separate enzymatic hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF), non-isothermal simultaneous saccharification and fermentation (NSSF), simultaneous saccharification and co-fermentation (SSCF), and consolidated bioprocessing (CBP). Furthermore, the by-products in ethanol from lignocellulosic materials, wastewater treatment, commercial status, and energy production and integration are reviewed.

Bioethanol is nowadays one of the main actors in the fuel market. It is currently produced from sugars and starchy materials, but lignocelluloses can be expected to be major feedstocks for ethanol production in the future. Two processes are being developed in parallel for conversion of lignocelluloses to ethanol, “acid-based” and “enzyme-based” processes. The current article is dedicated to review of progress in the “acid-based-hydrolysis” process. This process was used industrially in the 1940s, during wartime, but was not economically competitive afterward. However, intensive research and development on its technology during the last three decades, in addition to the expanding ethanol market, may revive the process in large scale once again. In this paper the ethanol market, the composition of lignocellulosic materials, concentrated- and dilute-acid pretreatment and hydrolysis, plug-flow, percolation, counter-current and shrinking-bed hydrolysis reactors, fermentation of hexoses and pentoses, effects of fermentation inhibitors, downstream processing, wastewater treatment, analytical methods used, and the current commercial status of the acid-based ethanol processes are reviewed.

Lignocellulosic biomass resources are renewable materials that can be converted to fermentable sugars and subsequently into ethanol. Water hyacinth (Eichhornia crassipes) is a cellulosic aquatic plant that has high carbohydrates, low lignin content, and notable reducing sugars content in its structure. Based on the literature review in the case of water hyacinth, the most frequently used pretreatment methods were acid and alkali, while ionic liquid and microwave-assisted methods were used rarely. The dominant sugars were glucose, xylose, galactose, arabinose, and mannose. Based on the findings, cellulase and S. cerevisiae were mostly used for enzymatic hydrolysis and fermentation of water hyacinth to ethanol, respectively. This review presents the recent studies in pretreatment, hydrolysis, and fermentation of water hyacinth biomass into ethanol. [ABSTRACT FROM AUTHOR]

As the worldwide demand for fuels and materials increases, fossil resources are decreasing and global warming is a concern, and thus the need for alternative solutions is high. In the industries of furniture and housing, particleboards are interesting materials, as they reutilize wastes from other industries (wood, agriculture) although they also rely on chemical binders that are petroleum-based and toxic. A very promising alternative is then clearly identified in finding ways to produce binderless boards and associated materials. This review considers the state of the art in the field of binderless board production, and other processes making it possible to turn raw plant fibers into structural materials without using any external chemistry. The mechanical properties and water resistance are collected and compared. Identified chemistry changes occurring during the thermo-compressive process are discussed with an aim towards understanding of the mechanisms of cohesion. [ABSTRACT FROM AUTHOR]

A characterization study on oil palm decanter cakes (OPDC) was performed to gain an in-depth understanding of the material's characteristics to aid in potential residual oil recovery. The OPDC was characterized by a high moisture content, high biodegradability, high organic content, and a nutrient-rich composition. Microscopic observation showed that the oil attachments in OPDC, and a vast majority of the droplets, were less than 50 µm in size. Furthermore, contact angle measurement revealed the hydrophilic and oleophilic characteristics of OPDC. Specifically, the contact angles of water and crude palm oil (CPO) with OPDC were both less than 45° with absorption rates of 0.0265 × 0.003 µL/s and 0.1042 × 0.05 µL/s, respectively. The OPDC is a fibrous material, and the surface area and pore size measured were 7.103 m2/g and 481.7 Å, respectively. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis results showed the functional groups and degradation properties of OPDC, respectively. [ABSTRACT FROM AUTHOR]

Agro-industrial wastes are the most abundant renewable resource on earth and are available in large quantities. However, the disposal of these wastes presents an increasing environmental problem. Recently, there has been a great interest in the exploitation of these wastes as lowcost raw materials for the production of value-added compounds as microbial enzymes by submerged or solid-state fermentation systems. This review focuses on alternatives for xylanase production using agroresidues as substrates. In recent years, the interest in xylanase, which plays an important role in the breakdown of xylan, has markedly increased due to its wide variety of biotechnological applications. Among several agro-industrial residues that have been intensively investigated, many, such as wheat bran, wheat straw, and sugarcane bagasse, are suitable and result in high yields of xylanase, leading to low production costs. In addition, many relatively unexplored residues, such as oil palm wastes, sorghum straw, and coffee by-products, are some of the most promising substrates for xylanase production, requiring further assessment. [ABSTRACT FROM AUTHOR]

High-pressure steam treatment (HPST) is a potential alternative method for the modification of lignocellulosic materials. The effect of HPST on oil palm mesocarp fibers (OPMF) was successfully investigated with treatment conditions of 170 ºC/ 0.82 MPa, 190 ºC/ 1.32 MPa, 210 ºC/ 2.03 MPa, and 230 ºC/ 3.00 MPa for 2 min. treatment time. Significant changes in the colour, smell, and mechanical properties of the samples were observed after the treatment. Scanning electron microscope (SEM) images revealed changes in the surface morphology of the OPMF after the pretreatment. The degradation of hemicelluloses and changes in the functional groups of the lignocellulosic components were identified using Fourier Transform Infrared (FTIR) and Thermogravimetric (TG) analysis. These results suggest that HPST is a promising method for the pretreatment of OPMF. [ABSTRACT FROM AUTHOR]

In order to prepare nanoparticles, corn cobs were treated with sodium hydroxide in the range 0-6 mole/litre (0-24% of sodium hydroxide on oven dry basis) at 165 °C for 1.5 h at a liquor to solid ratio of 4.5:1. The sample obtained at the optimised condition (4.5 mole/litre) was washed with deionised water, disintegrated, and filtered through 80 mesh screens. Powder thus obtained was delignified by acidified sodium chlorite and dried in a vacuum oven to constant weight. Dried powder was further separated by 270 mesh screens. An average particle size approximately equal to 22 nm was observed by Transmission Electron Microscopy (TEM). Its crystallinity was determined by XRD analysis. The aggregated particle size was observed in the micron range by Scanning Electron Microscopy (SEM). [ABSTRACT FROM AUTHOR]

Considering the mild degradation strength and the fact that it may be an organic matter reserve for the soil, in the past years lignocellulosic materials have been used as fibrous raw materials in the manufacture of biodegradable nutritive pots for the seedling in vegetable containerized production. This paper analyses the behavior of the nutritive pots made from biodegradable composites for the vegetable seedling production process, focusing on their mechanical strength properties and biodegradability. It was found that the biodegradability of composite materials obtained from a mixture of secondary cellulosic fibers, peat, and additives, is strongly influenced by the presence or absence of the rhizosphere effect and the synergistic relations set in the culture substrate between the plant roots and microorganisms, which develop permanently the recycling and solubilization of mineral nutrients. The results showed that the presence in the substrate of some complex populations made by heterotrophic bacteria favors full degradation of the pulp and lignin contained in the substrate and pots composition. Therefore, unlike the reference sample (plant-free), cultivated versions exhibited an intense biodegradation on the account of rhizosphere effect. [ABSTRACT FROM AUTHOR]

Traditional chemical industry depends on non-renewable fossil resources and is now facing great challenges. Lignocellulosic materials are the most abundant renewable resources in the world, and their efficient utilization provides a practical route to maintain sustainable development of chemical industry. Modern chemical technology as well as industrial biotechnology will play an important role in comprehensive utilization of lignocellulosic materials in an environmentally friendly way. Bio-refinery is a useful concept in use when considering lignocellulosic materials for a sustainable chemical industry.