Showing papers in "Bioresources in 2011"
TL;DR: In this paper, a review of limiting factors in utilization of technical lignins is presented, and four major classes of problems are identified, and approaches to overcoming these problems are suggested.
Abstract: The primary aim of modern biorefineries is the efficient conversion of lignocellulosic materials into valuable products. Sugars and oils can be converted into valuable chemicals, but processing of lignin is still a challenge. A vast amount of lignin is incinerated to produce process steam and energy, and only a very small part is used for the production of value-added products. Technical lignins are isolated as by-streams in lignocellulosic refineries, e.g., as kraft, soda, organosolv, and hydrolysis lignins, as well as lignosulphonates. They have a modified structure and contain impurities that are dependent on the processing method. The structure and the composition of technical lignins restrict their subsequent applications. This paper reviews limiting factors in utilization of technical lignins. Four major classes of problems are identified, and approaches to overcoming these problems are suggested.
544 citations
TL;DR: Application of white-rot fungi capabilities can offer environmentally friendly processes for utilising lignocelluloses over physical or chemical pretreatment, and the effect of biological pretreatment on biomass characteristics, and factors affecting biological pret treatment are reviewed.
Abstract: Lignocellulosic carbohydrates, i.e. cellulose and hemicellulose, have abundant potential as feedstock for production of biofuels and chemicals. However, these carbohydrates are generally infiltrated by lignin. Breakdown of the lignin barrier will alter lignocelluloses structures and make the carbohydrates accessible for more efficient bioconversion. White-rot fungi produce ligninolytic enzymes (lignin peroxidase, manganese peroxidase, and laccase) and efficiently mineralise lignin into CO2 and H2O. Biological pretreatment of lignocelluloses using white-rot fungi has been used for decades for ruminant feed, enzymatic hydrolysis, and biopulping. Application of white-rot fungi capabilities can offer environmentally friendly processes for utilising lignocelluloses over physical or chemical pretreatment. This paper reviews white-rot fungi, ligninolytic enzymes, the effect of biological pretreatment on biomass characteristics, and factors affecting biological pretreatment. Application of biological pretreatment for enzymatic hydrolysis, biofuels (bioethanol, biogas and pyrolysis), biopulping, biobleaching, animal feed, and enzymes production are also discussed.
270 citations
TL;DR: In this article, the authors proposed to use methylation of lignin macromolecules to increase the reactivity of the protein by forming catechol moieties in the protein.
Abstract: Lignin is readily available as a by-product from the pulp and paper industry. It is considered to be a promising substitute for phenol in phenol-formaldehyde (PF) resin synthesis, given the increasing concerns of the shortage of fossil resources and the environmental impact from petroleum-based products. One hurdle that prevents the commercial utilization of lignin is its low reactivity due to its chemical structure. Many efforts have been made to improve its reactivity by modification and/or depolymerization of lignin molecules. Methylolation and phenolation are the two most studied modification approaches aimed at introducing reactive functional groups to lignin molecules. Modified lignin from these two methods could partially replace phenol in PF resin synthesis. Demethylation of lignin could effectively increase the reactivity of lignin by forming catechol moieties in the lignin macromolecule. Other methods, including reduction, oxidation, and hydrolysis, have also been studied to improve the reactivity of lignin as well as to produce phenolic compounds from lignin. Most current methods of lignin modification are not economically attractive. One can expect that efforts will be continued, aimed at improving the utilization of lignin for value-added products.
250 citations
TL;DR: In this article, the authors consider how biosorption of dyes onto cellulose-related materials has the potential to address the concerns of highly visible, sometimes toxic, and sometimes resistant to biological breakdown; thus it is important to minimize their release into aqueous environments.
Abstract: Dyes used in the coloration of textiles, paper, and other products are highly visible, sometimes toxic, and sometimes resistant to biological breakdown; thus it is important to minimize their release into aqueous environments. This review article considers how biosorption of dyes onto cellulose-related materials has the potential to address such concerns. Numerous publications have described how a variety of biomass-derived substrates can be used to absorb different classes of dyestuff from dilute aqueous solutions. Progress also has been achieved in understanding the thermodynamics, kinetics, and chemical factors that control the uptake of dyes. Important questions remain to be more fully investigated, such as those involving the full life-cycle of cellulosic substrates that are used for the collection of dyes. Also, more work needs to be done in order to establish whether biosorption should be implemented as a separate unit operation, or whether it ought to be integrated with other water treatment technologies, including the enzymatic breakdown of chromophores.
242 citations
TL;DR: In this paper, different types of retting processes used for bast plants such as hemp, jute, flax, and kenaf, with an emphasis on Kenaf are reviewed.
Abstract: Retting is the main challenge faced during the processing of bast plants for the production of long fibre. The traditional methods for separating the long bast fibres are by dew and water retting. Both methods require 14 to 28 days to degrade the pectic materials, hemicellulose, and lignin. Even though the fibres produced from water retting can be of high quality, the long duration and polluted water have made this method less attractive. A number of other alternative methods such as mechanical decortication, chemical, heat, and enzymatic treatments have been reported for this purpose with mixed findings. This paper reviews different types of retting processes used for bast plants such as hemp, jute, flax, and kenaf, with an emphasis on kenaf. Amongst the bast fibre crops, kenaf apparently has some advantages such as lower cost of production, higher fibre yields, and greater flexibility as an agricultural resource, over the other bast fibres. The fibres produced from kenaf using chemical retting processes are much cleaner but low in tensile strength. Enzymatic retting has apparent advantages over other retting processes by having significantly shorter retting time and acceptable quality fibres, but it is quite expensive.
242 citations
TL;DR: In this article, the use of multiple-step procedures to obtain valuable sub-products, including nanocellulose, from rice husk was discussed, which can be used as additives and fillers in a very wide range of applications.
Abstract: The present work deals with the use of multiple-step procedures to obtain valuable sub-products, including nanocellulose, from rice husk. Each sub-product was characterized after every step by analyzing the chemical composition (mainly based on thermogravimetric analysis, Fourier transformed infrared spectra, and X-ray diffraction) and morphology (using visual observations and scanning electron microscopy). The results clearly showed that the selected procedure gave the possibility to separate silica in the first step and then to purify the resultant material, leading to nanocellulose production. All acquired sub-products can be used as additives and fillers in a very wide range of applications. The obtained results will be useful both from technological and academic points of view, mainly for people working in the field of biocomposites. The final material could give added value to a raw biomass material source such as rice husk.
187 citations
TL;DR: In this paper, the effect of hot compressed water (HCW) pretreatment within the temperature range 100 to 200 °C in a batch-type reactor on the structural changes of Tamarix ramosissima was investigated.
Abstract: As an initial step in an alternative use of woody biomass to produce bioethanol, this work was aimed at investigating the effect of hot compressed water (HCW) pretreatment within the temperature range 100 to 200 °C in a batch-type reactor on the structural changes of Tamarix ramosissima. The untreated and pretreated solid residues were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), solid-state cross polarization/magic angle spinning (CP/MAS), 13C NMR spectroscopy, and thermogravimetric analysis (TGA), as well as chemical methods. The results showed that HCW pretreatment solubilized mainly hemicelluloses and resulted in enriched cellulose and lignin content in the pretreated solids. It was found that the deposition of lignin droplets on the residual surfaces was produced during pretreatment under the hot water conditions above 140 °C. In addition, the removal of hemicelluloses and lignin re-localisation as a result of condensation reactions under the severe pretreatment condition may lead to an increase in cellulose crystallinity and thermal stability of biomass solid residues, thus consequently influencing the downstream digestibility of biomass for sugars and bioethanol production.
176 citations
TL;DR: In a previous work as discussed by the authors, we have presented an area of interest for the area of Ciencias Exactas, Quimicas, and Naturales at the Universidad Nacional de Misiones in Argentina.
Abstract: Fil: Area, Maria Cristina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas, Quimicas y Naturales; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Nordeste; Argentina
161 citations
TL;DR: A field experiment was conducted on the effect of biochar (BC) amendment on Cd uptake by rice (Oryza sativa L.) in a contaminated paddy in 2009 and 2010 as mentioned in this paper.
Abstract: A field experiment was conducted on the effect of biochar (BC) amendment on Cd uptake by rice (Oryza sativa L.) in a contaminated paddy in 2009 and 2010. BC was applied as a basal soil amendment before rice transplantation in 2009 at rates of 0, 10, 20, 40t ha-1, and rice yield and Cd uptake were monitored in both 2009 and 2010. The BC amendment significantly increased soil pH by 0.15-0.33 units in 2009 and 0.24-0.38 units in 2010, and decreased CaCl2 extracted Cd in soil by 32.0%-52.5% in 2009 and 5.5%-43.4% in 2010, respectively. Under BC amendment at 10, 20, 40 t ha-1, rice grain Cd concentration was observed to be reduced by 16.8%, 37.1%, and 45.0% in 2009 and by 42.7%, 39.9%, and 61.9% in 2010, while the total plant Cd uptake was found to decrease by 28.1%, 45.7%, and 54.2% in 2009 and by 14.4%, 35.9%, and 45.9% in 2010, respectively. Such effect of BC amendment on reducing Cd plant uptake has profound implications among those using bioresources for field application. Finally, BC amendment in combination with low Cd cultivars may offer a basic option to reduce Cd levels in rice as well as to reduce greenhouse gas emissions in rice agriculture in contaminated paddies.
159 citations
Journal Article•
TL;DR: In this paper, three types of alkaline lignins were characterized in terms of their structures and thermal properties: kraft lignin (LIG-1), soda-rice straw (SRS straw), and soda-wheat straw (SLIG-3), using FTIR and 1H-NMR methods to determine their structure.
Abstract: Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignins in thermosetting materials. To evaluate the potential application of lignin raw materials in phenol formaldehyde and epoxy resins, three types of alkaline lignins were characterized in terms of their structures and thermal properties. The lignin samples analyzed were kraft lignin (LIG-1), soda–rice straw lignin (LIG-2), and soda-wheat straw lignin (LIG-3). FTIR and 1H-NMR methods were used to determine their structure. Gel permeation chromatography (GPC) was used to determine the molecular weight distribution (MWD). Differential scanning calorimetry (DSC) was used to measure the glass transition temperature (Tg), and thermogravimetric analysis (TGA) to determine the thermal stability of lignin samples. Results showed that kraft lignin (LIG-1) has moderate hydroxyl-group content, is rich in G-type units, and has good thermal stability. These properties make it more suitable for direct use in phenol formaldehyde resins, and it is therefore a good raw material for this purpose. The alkaline soda-rice straw lignin (LIG-2) with a high hydroxyl-group content and excellent thermal stability is most suited to preparing lignin-based epoxy resins.
142 citations
TL;DR: In this paper, kraft lignin-based epoxy resins were obtained by the epoxidization reaction, using the kraft Lignin recovered directly from pulping liquor and modified by a methylolation reaction.
Abstract: Epoxidization is an interesting way to develop a new application of lignin and therefore to improve its application potential. In this work, kraft lignin-based epoxy resins were obtained by the epoxidization reaction, using the kraft lignin recovered directly from pulping liquor and modified by a methylolation reaction. The methylolated lignins were obtained by the reaction of original kraft lignin with formaldehyde and glyoxal, which is a less volatile and less toxic aldehyde. 1H-NMR spectroscopy showed that methylolated kraft lignin has more hydroxymethyl groups than glyoxalated kraft lignin. For the epoxidization reaction we studied the influence of the lignin:NaOH (w/w) ratio, temperature, and time of the reaction on the properties of the prepared epoxidized lignins. The structures of lignin-based epoxy resins were followed by epoxy index test and FTIR spectroscopy. Optimal conditions were obtained for lignin-based epoxy resin produced at lignin/NaOH = 1/3 at 70 oC for 3h. Thermogravimetry analysis (TGA) revealed that the epoxidization enhances the thermal stability of lignins and may allow a wider temperature range for applications with lignin epoxy-PF blends.
TL;DR: In this paper, it was found that adding fillers resulted in films with lower densities but also lower water vapor transmission rates, which was hypothesized to be due to decreased water vapor solubility in the films.
Abstract: Microfibrillated celluloses (MFCs) have mechanical properties sufficient for packaging applications, but lack in comparison to petroleum-based plastics in water vapor barrier properties. These properties can be modified by the use of mineral fillers, added within the film structure, or waxes, as surface coatings. In this investigation it was found that addition of fillers resulted in films with lower densities but also lower water vapor transmission rates. This was hypothesized to be due to decreased water vapor solubility in the films. Associated transport phenomena were described by the Knudsen model for diffusion but due to the limited incorporation of chemical factors in the model, accurate prediction of pore diameters for filled films was not possible. Modeling the filled-films with Fick’s equation, however, takes into account chemical differences, as observed by the calculated tortuosity values. Remarkably, coating with beeswax, paraffin, and cooked starch resulted in films with water vapor transmission rates lower than those for low density polyethylene. These coatings were modeled with a three-layer model which determined that coatings were more effective in reducing WVTR.
TL;DR: In this paper, a new strain of Trametes versicolor IBL-04 was reported to produce higher activities of MnP, followed by laccase and LiP.
Abstract: This paper reports the production of ligninase enzymes by a new strain of Trametes versicolor IBL-04 producing a novel pattern of ligninolytic enzymes with highest MnP activities followed by LiP and laccase. In previous studies Trametes versicolor has been reported to produce higher activities of MnP, followed by laccase and LiP. Lignocellulosic substrates including wheat straw, rice straw, banana stalks, corncobs, corn stover, and sugarcane bagasse were used in solid state fermentation (SSF) for the production of ligninases including peroxidase (LiP), manganese peroxidase (MnP), and laccase by Trametes versicolor IBL-04. Maximum production of MnP (998 U/mL), LiP (620 U/mL), and Laccase (49.7 U/mL) was observed after 5 days in the SSF medium containing 5g rice straw (60% w/w moisture) in still culture SSF. Moisture, pH, temperature, inoculums size, additional carbon and nitrogen sources, and surfactants had a significant influence on ligninase synthesis by the fungus. Production of ligninases was substantially enhanced by optimizing SSF production process. Maximum MnP (1775 U/mL), LiP (1663 U/mL), and laccase (99 U/mL) were produced when rice straw (5g) at 66.6 % moisture (w/w) receiving 5ml inoculum was incubated at pH 4.0 and 30oC in the presence of maltose (1% w/w) as carbon source, urea (0.2% w/w) as nitrogen source and 1mM Tween-80 (0.3 ml) as surfactant.
TL;DR: In this paper, the chemical structure of the resulting cellulose fibers was studied by Fourier Transform Infrared (FTIR) spectroscopy Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) techniques.
Abstract: Cellulose fibers were isolated from sugarcane bagasse in three stages Initially sugarcane bagasse was subjected to a pre-treatment process with hydrolyzed acid to eliminate hemicellulose Whole cellulosic fibers thus obtained were then subjected to a two-stage delignification process and finally to a bleaching process The chemical structure of the resulting cellulose fibers was studied by Fourier Transform Infrared (FTIR) spectroscopy Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the effects of hydrolysis, delignification, and bleaching on the structure of the fibers Two different thermal analysis techniques were used to study the bleaching cellulose fibers These techniques confirmed that cellulose fibers were isolated from sugarcane bagasse A future goal is to use these fibers as reinforcement elements in composites, organic-inorganic hybrid, and membranes for nanofiltration
TL;DR: In this paper, the effect of layering pattern on dynamic mechanical properties (storage modulus, loss modulus and tan δ) was investigated as a function of temperature, and the overall results showed that hybridization with jute fibers enhanced the dynamic mechanical and thermal properties.
Abstract: Dynamic mechanical and thermal analysis of oil palm empty fruit bunches (EFB)/jute fiber reinforced epoxy hybrid composites were carried out. The effect of layering pattern on dynamic mechanical properties (storage modulus (E’), loss modulus (E”), and tan δ) was investigated as a function of temperature. The storage modulus (E’) was found to be decreased with temperature in all cases, and hybrid composites had almost the same values of E’ at glass transition temperature (Tg). The tan δ peak height was minimum for jute composites and maximum for epoxy matrix. Layering pattern affected the dynamic mechanical properties of hybrid composites. Cole-Cole analysis was carried out to understand the phase behaviour of the composite samples. Thermogravimetric analysis (TGA) results indicated an increase in thermal stability of pure EFB composite with the incorporation of jute fibers. The overall results showed that hybridization with jute fibers enhanced the dynamic mechanical and thermal properties.
TL;DR: In this article, the kraft pulping delignification rates of Eucalyptus urograndis, E. globulus, maple, red oak, birch, red alder, cottonwood, and acacia were analyzed via quantitative 13C NMR spectroscopy.
Abstract: In an attempt to explain variations in delignification behaviors among different hardwood species, the kraft pulping delignification rates of Eucalyptus urograndis, E. nitens, E. globulus, sweet gum, maple, red oak, birch, red alder, cottonwood, and acacia were obtained and correlated with their respective lignin chemical structures. Since H-factor for hardwood is calculated based on the softwood activation energy (Ea) value, a comparison between softwood vs. hardwood activation energy was also performed. Lignin was isolated by a modified isolation protocol, using alkaline pretreatment of the wood prior to isolation. The lignin preparations were analyzed via quantitative 13C NMR spectroscopy. Substantial variations were found among the hardwood species studied. A linear correlation between the kraft delignification rate and the amount of syringyl units was found. Activation energy values obtained for kraft pulping of hardwoods were very similar and almost identical to the value obtained for softwood. Birch was the only species with outlier behavior.
TL;DR: In this article, Nanocrystalline cellulose (NCC) with small particle size and high crystallinity was prepared via the combined method of ultrasonication and acid hydrolysis from bleached softwood kraft pulp (BSKP).
Abstract: Nanocrystalline cellulose (NCC) with small particle size and high crystallinity was prepared via the combined method of ultrasonication and acid hydrolysis from bleached softwood kraft pulp (BSKP). Scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy were used for determination of morphology, crystal structure, and surface chemical groups. Thermal behavior was analyzed by thermogravimetric analysis. The analyses revealed that rod-shaped NCC particles with diameter of 10 to 20 nm can be obtained. Ultrasonication can induce cellulose folding, surface erosion, and external fibrillation of BSKP, together with the shorter average length of NCC (96 nm) than that prepared without ultrasonication (150 nm). Due to the smaller size and larger number of free ends of chains, the thermal stability of NCC was lower than BSKP. The degradation of BSKP exhibited one significant pyrolysis stage within the range of 300 to 420 °C. In contrast, UH-NCC exhibited three pyrolysis stages within the range of 210 to 450 °C. NCC prepared with ultrasonication decomposed at lower temperature and over a wider temperature range, together with higher char yield of 43% (compared with 27% for that without ultrasonication). The obtained NCC had similar surface chemical structures but higher crystallinity (82%) compared with that of the starting BSKP (74%).
Journal Article•
TL;DR: Wood modification is a generic term describing the application of chemical, physical, or biological methods to alter the properties of the material as discussed by the authors The aim is to get better performance from the wood, resulting in improvements in dimensional stability, decay resistance, weathering resistance, etc.
Abstract: Wood modification is a generic term describing the application of chemical, physical, or biological methods to alter the properties of the material. The aim is to get better performance from the wood, resulting in improvements in dimensional stability, decay resistance, weathering resistance, etc. It is essential that the modified wood is non-toxic in service and that disposal at the end of life does not result in the generation of any toxic residues. Over the past five years there have been significant developments in wood modification technologies, especially in the commercial sector. This technology is here to stay.
Journal Article•
TL;DR: In this article, the physical characteristics of sawdust relative to its use as an adsorbent for removal of an acid dye (Orange G) from aqueous solutions were investigated.
Abstract: The present paper aims to investigate the physical characteristics of sawdust relative to its use as an adsorbent for removal of an acid dye (Orange G) from aqueous solutions. The raw sawdust was sieved to have a uniform size and was activated by sulphuric acid by refluxing the content at 60 oC for 4 h. Surface morphology and surface functional groups of both raw and modified sawdust samples were investigated by Scanning Electron Microscope (SEM), Energy Dispersive X-ray Analysis (EDX), Fourier Transformation Infrared (FTIR), and elemental analysis. All these analyses displayed significant change in the structure of the sawdust. The data obtained from batch adsorption experiments for the removal of the selected dye confirmed that adsorption characteristics of the modified sawdust were better than those of raw sawdust.
TL;DR: In this article, an oil palm empty fruit bunches (EFB)/woven jute fibres (Jw) reinforced epoxy hybrid composites were prepared by hand lay-up technique by keeping the EFB/ woven jute fibre weight ratios constant, i.e. 4:1.
Abstract: Oil palm empty fruit bunches (EFB)/woven jute fibres (Jw) reinforced epoxy hybrid composites were prepared by hand lay-up technique by keeping the EFB/ woven jute fibre weight ratios constant, i.e. 4:1. By combining oil palm EFB and woven jute fibre, it is possible to take advantage of both fibres while at the same time suppressing their less desirable qualities. These hybrids provide a new type of sandwich structure with a good skin-core adhesion and the potential for their applications as cost-effective sandwich construction. The effect of the layering pattern on the water absorption and thickness swelling of the hybrid composites was studied. It was observed that water diffusion occurred in the composites, depending on the fibre type as well as the layering pattern. EFB fibre composites exhibited maximum water absorption during the whole duration of immersion. The hybridization of oil palm EFB composites with woven jute fibre showed beneficial effects on both the water absorption and thickness swelling by improving fibre/matrix bonding.
Journal Article•
TL;DR: In this paper, the effect of natural weathering in ground contact on biological resistance, modulus of rupture, and color stability of heat-treated alder wood was investigated, and chemical composition of weathered wood was also studied by FTIR-ATR spectra.
Abstract: The objective of this study was to investigate the effect of natural weathering in ground contact on biological resistance, modulus of rupture, and color stability of heat-treated alder wood. Chemical composition of weathered wood was also studied by FTIR-ATR spectra. Wood stakes were heated at 150, 180, and 200°C for periods of 2, 6, and 10 hours, and the stakes were subsequently exposed to natural weathering and decay in a field area located in the north of Turkey for 3 years. The decay index of heat-treated stakes was lower than that of the controls. The weight loss prevention ratio had an increasing tendency with increasing treatment temperature and length of time. Depending on the treatment parameters, heat treatment reduced the modulus of rupture by up to 50%; however decay caused by soil micro-organisms gave rise to a greater loss of modulus of rupture than heat. Weathering processes caused remarkable color changes in the samples. FTIR-ATR spectra showed significant deformations and degradations in wood components, especially in the hemicelluloses of heat-treated samples. Degradation of hemicelluloses increased with an increase in heat temperature and exposure time.
TL;DR: In this article, the TEMPO-NaBr-NaClO system with ultrasonic treatment was used to produce high carboxylate content cellulose nanocrystals, yielding a stable and well dispersed aqueous suspension.
Abstract: Cotton linter pulp was oxidized in the TEMPO-NaBr-NaClO system with ultrasonic treatment, and cellulose nanocrystals having high carboxylate content were produced directly. Results showed that the C6 primary hydroxyl group of cellulose fiber was converted to the carboxylate group, whose amount could be up to 1.66 mmol/g. During the oxidizing reaction, some of the amorphous region in the cellulose fiber was modified and gradually hydrolyzed, but the crystalline region still remained. It was also shown by TEM (Transmission electron microscopy) that the widths of cellulose nanocrystals were approximately 5-10 nm, and the lengths were approximately 100-400 nm. The high carboxylate content cellulose nanocrystals could be produced in one step by this method, yielding a stable and well dispersed aqueous suspension.
TL;DR: In this article, a supply chain and delivered cost model for seven feedstocks (loblolly pine, Eucalyptus, natural hardwood, switchgrass, Miscanthus, sweet sorghum, and corn stover) was built, simulating a supply of 453,597 dry tons per year to a biorefinery.
Abstract: Supply chain and delivered cost models for seven feedstocks (loblolly pine, Eucalyptus, natural hardwood, switchgrass, Miscanthus, sweet sorghum, and corn stover) were built, simulating a supply of 453,597 dry tons per year to a biorefinery Delivered cost of forest-based feedstocks ranged from $69 to $71 per dry ton On the other hand, delivered cost of agricultural biomass ranged from $7760 to $10250 per dry ton The total production area required for fast growing feedstocks was estimated as between 22,500 to 27,000 hectares, while the total production area for feedstocks with lower biomass productivity ranged from 101,200 to 202,300 hectares (corn stover and natural hardwood, respectively) Lower delivered cost per ton of carbohydrate and million BTU were found for loblolly pine, Eucalyptus, and natural hardwood In addition, agricultural biomass had higher delivered costs for carbohydrate and energy value
TL;DR: In this paper, the adsorption of different polysaccharides and cellulose derivatives on cellulose nanofibril films was compared using Quartz Crystal Microbalance with Dissipation (QCM-D).
Abstract: The objective of this work was to compare the adsorption of different polysaccharides and cellulose derivatives on cellulose nanofibril films. Cellulose films having the native cellulose I structure were prepared from hardwood kraft pulp by extensive mechanical disintegration. Further fractionation enabled the preparation of reproducible, nanometer-scale thickness films. Systematic comparison by Quartz Crystal Microbalance with Dissipation (QCM-D) showed that various industrially available galactomannans have almost as good affinity to cellulose surface as xyloglucan and that most of the polysaccharides attach irreversibly to cellulose nanofibrils at low pH (4.5) and intermediate ionic strength (10 mM). SPR results support the QCM-D findings. Atomic Force Microscopy (AFM) imaging and Digital Pulsed Force Mode (DPFM) measurements further confirmed that a uniform non-aggregated layer of polysaccharides was formed that changed the properties of the NFC film.
Journal Article•
TL;DR: High thermo-stability, low KM and high Vmax features of this novel MnP isolated from culture filtrate of T. versicolor IBL-04 suggests its suitability for various industrial and biotechnological applications.
Abstract: A novel manganese peroxidase (MnP) produced by an indigenous white rot fungal strain Trametes versicolor IBL-04 in solid state medium of corncobs was purified and characterized. The fungus produced 964U/mL MnP in the presence of additional carbon (glucose) and nitrogen (yeast extract) supplements added at a C:N ratio of 25:1, 1mM Tween-80 (1mL), 1mM MnSO4 (1mL), and 1mM CuSO4 (1mL). The MnP was purified by ammonium sulfate fractionation (65% saturation) and dialysis, followed by Sephadex G-100 gel filtration chromatography. Purification procedures resulted in 2.4-fold purification with an overall yield and specific activity of 3.4% and 660 U/mg, respectively. The purified MnP was monomeric of molecular weight of 43 kDa, showing a single band on sodium dodecyl sulfate poly acrylamide gel electrophoresis (SDS-PAGE). The enzyme was optimally active at pH 5 and 50oC and was stable for 1 h over a broad range of pH (4-7) and temperature (40-65oC). Kinetic constants KM and Vmax of purified MnP were 70 µM and 540 U/mL for MnSO4 substrate. The effect of possible activators and inhibitors of enzyme were also investigated, and it was observed that EDTA, Cystein, and Ag+ caused MnP inhibition and inactivation to different extents, whereas MnP was activated by 4 and 3 mM of Cu2+ and Fe2+, respectively. High thermo-stability, low KM and high Vmax features of this novel MnP isolated from culture filtrate of T. versicolor IBL-04 suggests its suitability for various industrial and biotechnological applications.
TL;DR: In this paper, the intrinsic tensile properties of SGW fibers were analyzed and compared to fiberglass PP composites, as well as the fiber orientation factor and the interfacial shear strength of the current composites.
Abstract: Stone groundwood (SGW) is a fibrous matter commonly prepared in a high yield process, and mainly used for papermaking applications. In this work, the use of SGW fibers is explored as reinforcing element of polypropylene (PP) composites. Due to its chemical and superficial features, the use of coupling agents is needed for a good adhesion and stress transfer across the fiber-matrix interface. The intrinsic strength of the reinforcement is a key parameter to predict the mechanical properties of the composite and to perform an interface analysis. The main objective of the present work was the determination of the intrinsic tensile strength of stone groundwood fibers. Coupled and non-coupled PP composites from stone groundwood fibers were prepared. The influence of the surface morphology and the quality at interface on the final properties of the composite was analyzed and compared to that of fiberglass PP composites. The intrinsic tensile properties of stone groundwood fibers, as well as the fiber orientation factor and the interfacial shear strength of the current composites were determined.
TL;DR: In this paper, the utility of pea peel waste, whey as well as wheat starch hydrolysate in cellulase production was discussed, and it was observed that 30 oC temperature and pH 5.0 are the most favorable conditions for cellulase generation by T. reesei.
Abstract: A wide variety of waste bioresources are available on our planet for conversion into bioproducts. In the biological systems, microorganisms are used to utilize waste as an energy source for the synthesis of valuable products such as biomass proteins and enzymes. The large quantities of byproducts generated during the processing of plant food involve an economic and environmental problem due to their high volumes and elimination costs. After isolation of the main constituent, there are abundant remains which represent an inexpensive material that has been undervalued until now. Pea peel waste is one of the undervalued, unused sources of energy that can serve as a potential source for cellulase production. Batch experiments have been performed, using pea peel waste as a carbon source for cellulase production under solid state cultivation by Trichoderma reesei. It was observed that 30 oC temperature and pH 5.0 are the most favorable conditions for cellulase production by T. reesei. FPase activity significantly increases by incorporation of whey as well as wheat starch hydrolysate in the basal salt media used in the production study. The present study describes the utility of pea peel waste, whey as well as wheat starch hydrolysate in cellulase production by T. reesei. The utilization of economically cheap, pea peel waste for cellulase production could be a novel, cost effective, and valuable approach in cellulase production as well as in solid waste management.
TL;DR: In this paper, the deinking of photocopier paper was examined using chemicals and a commercial cellulase enzyme, and the results showed that the enzyme used in the present work performed better than the conventional chemicals used for deinking.
Abstract: The utilization of post-consumer papers in the production of new paper products is increasing all over the world in recent years. Recycling of photocopier paper is a major problem due to difficulty in removal of non-impact ink. Enzymes offer potential advantages in ecofriendly deinking of recovered paper. In this study the deinking of photocopier paper was examined using chemicals and a commercial cellulase enzyme. Parameters of deinking experiments were optimized for hydrapulping. The ink was removed by flotation and washing processes. Then these parameters were compared in terms of ink removal ability of the process, as well as optical and strength properties of the deinked paper. The application of enzymatic deinking improved ink removal efficiency by 24.6% and freeness by 21.6% with a reduction in drainage time of 11.5% in comparison to those obtained with chemical deinking. The physical properties, namely burst index and tensile index, were observed to improve by 15.3% and 2.7%, respectively and brightness and tear index decreased by 2.1% and 21.9%, respectively. Results of deinking efficiency of photocopier paper showed that the enzyme used in the present work performed better than the conventional chemicals used for deinking.
TL;DR: In this article, the performance of rice husk powder (RHP) filled polypropylene (PP)/ recycled acrylonitrile butadiene rubber (NBRr) biocomposites with and without coupling agent, γ-aminopropyltrimethoxysilane (APS), were investigated.
Abstract: The performance of rice husk powder (RHP) filled polypropylene (PP)/ recycled acrylonitrile butadiene rubber (NBRr) biocomposites with and without coupling agent, γ-aminopropyltrimethoxysilane (APS), were investigated. The composites with different RHP filler loading (0 to 30 phr) were prepared in a Haake internal mixer. Mechanical properties, swelling behavior, and water absorption of PP/NBRr/RHP were studied. Increasing RHP loading in PP/NBRr/RHP biocomposites increased processing torque, tensile modulus, water absorption, and swelling in oil but decreased the tensile strength and elongation at break of the biocomposites. The γ-APS treated RHP composites exhibited higher processing torque, tensile strength, and tensile modulus but lower elongation at break when compared to untreated RHP composites. This is due to strong bonding between γ-APS treated RHP filler and PP/NBRr matrices. These findings were well supported by micrographs from the morphology studies. The γ-APS treatment on RHP improved the adhesion between RHP fiber and PP/NBRr polymer matrices, which led to less water and oil absorption into PP/NBRr/RHP/ biocomposites.
TL;DR: In this article, a green liquor pretreatment pathway for the efficient conversion of lignocellulosic biomass into ethanol was proposed, which is used worldwide in hundreds of kraft pulp mills.
Abstract: Green liquor pretreatment, a technology presently used worldwide in hundreds of kraft pulp mills, is proposed in this work as a potential pretreatment pathway for the efficient conversion of lignocellulosic biomass into ethanol. Mixed southern hardwood, eucalyptus, and loblolly pine were evaluated through process simulations in two investment scenarios: a greenfield mill scenario and a repurposing scenario, using existing kraft pulp mill assets for cellulosic ethanol production. Several advantages come with this concept: i) proven technology (both process and equipment), ii) chemical and energy recovery in place, iii) existing fiber supply chain, and iv) experienced labor force around the mill. Ethanol yields through enzymatic hydrolysis of pretreated fibers were highest in natural mixed hardwood and eucalyptus (280-285 liters of ethanol per dry ton of biomass) and lowest in loblolly pine (273 liters per dry ton of biomass). Natural hardwood and eucalyptus in the repurposing scenario form the most profitable combinations with an IRR of about 19%, mainly due to low capital expenditure (CAPEX) (per liter of ethanol), low enzyme costs, and higher ethanol yield (compared to loblolly pine). Production cost (in the repurposing scenario) was estimated at $2.51 per gallon of ethanol (or $0.66 per liter), cash cost at $2.14 gallon-1 (or $0.57 per liter), and CAPEX at $3.15 gallon-1 (or $0.83 per liter). Repurposing existing closed mills creates a potential alternative to ramp up in the task of producing alternative lignocellulosic biofuels.