Manufacturing of bioethylene via dehydration of bioethanol is an alternative to the fossil‐based ethylene production and decreases the environmental consequences for this chemical commodity. A few ...industrial plants that utilize 1st generation bioethanol for the bioethylene production already exist, although not functioning without subsidiaries. However, there is still no process producing ethylene from 2nd generation bioethanol. This study is divided into two parts. Different ethanol and ethylene production methods, the process specifications and current technologies are briefly discussed in the first part. In the second part, a techno‐economic analysis of a bioethylene plant was performed using Aspen® plus and Aspen Process Economic Analyzer, where different qualities of ethanol were considered. The results show that impurities in the ethanol feed have no significant effect on the quality of the produced polymer‐grade bioethylene. The capacity of the ethylene storage tank significantly affects the capital costs of the process.
Bioethylene production from bioethanol is considered an alternative to the fossil‐based route. Although processes for the use of 1st generation bioethanol already exist, 2nd generation bioethanol has so far not been covered. This review summarizes different production methods and analyses the effects of impurities in the ethanol as well as the storage tank capacities on the overall process costs.
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•Bioconversion of sweet sorghum stalks was greatly improved by organosolv pretreatment.•92% of theoretical yield in biogas production (270% improvement) was obtained.•High sugar yield ...of 83% via treatment with 50% ethanol, 1% sulfuric acid, at 140°C was achieved.•Adding acid can improve hydrolysis and ethanol production yield but not biogas yield.•Lignin and xylan contents and cellulose crystallinity were significantly reduced.
Improvement of bioconversion of sweet sorghum stalks to ethanol and biogas by organosolv pretreatment was investigated. The pretreatments were carried out at 100–160°C in the presence or absence of sulfuric acid (as a catalyst) using ethanol (as an organic solvent) for 30min. After evaporation of the solvent (ethanol), the pretreated solids (bagasse) and the liquid fraction (liquor) were subjected to anaerobic digestion for 50 days. The greatest biomethane yield, achieved from the mixture of liquor and bagasse, was 278ml CH4/g VS, corresponding to 92% of theoretical yield and showing 270% improvement compared to the methane yield obtained from untreated stalks. The enzymatic hydrolysis of the untreated stalk and the obtained bagasse was conducted at 45°C for 96h using 20 FPU cellulase and 50 IU β-glucosidase per gram of the substrate. Hydrolysis of the untreated stalk resulted in a low sugar yield (34.1% of the theoretical yield). The highest sugar yield (77% of the theoretical yield) was obtained after pretreatment with 50% ethanol and 1% sulfuric acid at 140°C. Accordingly, ethanol yield from the respective organosolv pretreated material showed a two-fold improvement compared to the untreated substrate. Ethanol production from liquor ended with a maximum yield of 65.7% after pretreatment with 50% ethanol at 100°C in the absence of acid. The compositional and FTIR analyses showed that organosolv pretreatment at elevated temperatures significantly reduced the lignin and xylan contents and the cellulose crystallinity.
Adipic acid, an abundant and nontoxic compound, was used to dissolve and cross-link chitosan. After the preparation of chitosan films through casting technique, the in situ amidation reaction was ...performed at 80-100 °C as verified by Fourier transform infrared (FT-IR). The reaction was accompanied by the release of water which was employed to investigate the reaction kinetics. Accordingly, the reaction rate followed the first-order model and Arrhenius equation, and the activation energy was calculated to be 18 kJ/mol. Furthermore, the mechanical properties of the chitosan films were comprehensively studied. First, optimal curing conditions (84 °C, 93 min) were introduced through a central composite design. In order to evaluate the effects of adipic acid, the mechanical properties of physically cross-linked (uncured), chemically cross-linked (cured), and uncross-linked (prepared by acetic acid) films were compared. The use of adipic acid improved the tensile strength of uncured and chemically cross-linked films more than 60% and 113%, respectively. Finally, the effect of cellulose nanofibrils (CNFs) on the mechanical performance of cured films, in the presence of glycerol as a plasticizer, was investigated. The plasticized chitosan films reinforced by 5 wt % CNFs showed superior properties as a promising material for the development of chitosan-based biomaterials.
Survivors of traumatic brain injury (TBI) often develop chronic neurological, neurocognitive, psychological, and psychosocial deficits that can have a profound impact on an individual’s wellbeing and ...quality of life. TBI is also a common cause of acquired epilepsy, which is itself associated with significant behavioral morbidity. This review considers the clinical and preclinical evidence that post-traumatic epilepsy (PTE) acts as a ‘second-hit’ insult to worsen chronic behavioral outcomes for brain-injured patients, across the domains of emotional, cognitive, and psychosocial functioning. Surprisingly, few well-designed studies have specifically examined the relationship between seizures and behavioral outcomes after TBI. The complex mechanisms underlying these comorbidities remain incompletely understood, although many of the biological processes that precipitate seizure occurrence and epileptogenesis may also contribute to the development of chronic behavioral deficits. Further, the relationship between PTE and behavioral dysfunction is increasingly recognized to be a bidirectional one, whereby premorbid conditions are a risk factor for PTE. Clinical studies in this arena are often challenged by the confounding effects of anti-seizure medications, while preclinical studies have rarely examined an adequately extended time course to fully capture the time course of epilepsy development after a TBI. To drive the field forward towards improved treatment strategies, it is imperative that both seizures and neurobehavioral outcomes are assessed in parallel after TBI, both in patient populations and preclinical models.
Traumatic brain injury (TBI) during early childhood is associated with a particularly high risk of developing social behavior impairments, including deficits in social cognition that manifest as ...reduced social interactions, with profound consequences for the individuals’ quality of life. A number of pre-injury, post-injury, and injury-related factors have been identified or hypothesized to determine the extent of social behavior problems after childhood TBI. These include variables associated with the individual themselves (e.g. age, genetics, the injury severity, and extent of white matter damage), proximal environmental factors (e.g. family functioning, parental mental health), and more distal environmental factors (e.g. socioeconomic status, access to resources). In this review, we synthesize the available evidence demonstrating which of these determinants influence risk versus resilience to social behavior deficits after pediatric TBI, drawing upon the available clinical and preclinical literature. Injury-related pathology in neuroanatomical regions associated with social cognition and behaviors will also be described, with a focus on findings from magnetic resonance imaging and diffusion tensor imaging. Finally, study limitations and suggested future directions are highlighted. In summary, while no single variable can alone accurately predict the manifestation of social behavior problems after TBI during early childhood, an increased understanding of how both injury and environmental factors can influence social outcomes provides a useful framework for the development of more effective rehabilitation strategies aiming to optimize recovery for young brain-injured patients.
•Biorefinery of biomass of the macroalgae, Nizimuddinia zanardini, was investigated.•The biomass mainly contained mannitol, alginic acid, potassium, proteins, and glucan.•A valuable seaweed extract ...and also alginic acid were separated from the biomass.•The rest of biomass was converted to ethanol or biogas through fermentation process.•The biofuel yields were enhanced by hot water or dilute acid pretreatments.
Nizimuddinia zanardini macroalgae, harvested from Persian Gulf, was chemically characterized and employed for the production of ethanol, seaweed extract, alginic acid, and biogas. In order to improve the products yields, the biomass was pretreated with dilute sulfuric acid and hot water. The pretreated and untreated biomasses were subjected to enzymatic hydrolysis by cellulase (15FPU/g) and β-glucosidase (30IU/g). Hydrolysis yield of glucan was 29.8, 82.5, and 72.7g/kg for the untreated, hot-water pretreated, and acid pretreated biomass, respectively. Anaerobic fermentation of hydrolysates by Saccharomycescerevisiae resulted in the maximum ethanol yield of 34.6g/kg of the dried biomass. A seaweed extract containing mannitol and a solid residue containing alginic acid were recovered as the main byproducts of the ethanol production. On the other hand, the biogas yield from the biomass was increased from 170 to 200m3 per ton of dried algae biomass by hot water pretreatment.
The biodegradation of PLA and PLA-Jute (64/36) in an aqueous media with Aspergillus flavus CCUG 28296, as well as its cell-free enzyme extract, was investigated through their physical, molecular, and ...thermal characterization. Results indicated that the thicknesses of the fungal treated PLA and PLA-jute samples during seven months have reduced by 52% and 63%, respectively while for the enzyme-treated samples, 45% and 49% reduction in the thickness has occurred. Moreover, the gel permeation chromatography (GPC) revealed a substantial decrease (about 75%) in the weight average molecular weight (Mw) of PLA and PLA-Jute treated with fungus, which confirmed the effective performance of A. flavus on the biological degradation of PLA. The obtained results were further supported by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) of the treated and control samples as well. Interestingly, the observed reduction in the Mw of PLA in PLA-Jute was 64% after the enzymatic treatment, while for the unblended PLA, it was just about 32%. These results pointed to the synergistic effect of jute on PLA degradation because of the promiscuous activity of the effective enzymes on jute degradation, which could accelerate the PLA decomposition.
•Biodegradation of PLA and PLA/Jute samples were investigated without any types of pre-treatments.•The fungus and its cell free enzyme solution were significantly effective in biodegradation of the PLA.•Addition of Jute as a lignocellulosic material to the PLA had a synergistic effect on the PLA degradation.
Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biobased and biodegradable polymer. This polymer is considered promising, but it is also rather expensive. The objective of this study was to ...compound PHBV with three different organic fillers considered waste: human hair waste (HHW), sawdust (SD) and chitin from shrimp shells. Thus, the cost of the biopolymer is reduced, and, at the same time, waste materials are valorised into something useful. The composites prepared were characterised by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile strength and scanning electron micrograph (SEM). Tests showed that chitin and HHW did not have a reinforcing effect on tensile strength while the SD increased the tensile strength at break to a certain degree. The biodegradation of the different composites was evaluated by a soil burial test for five months. The gravimetric test showed that neat PHBV was moderately degraded (about 5% weight loss) while reinforcing the polymer with organic waste clearly improved the biodegradation. The strongest biodegradation was achieved when the biopolymer was compounded with HHW (35% weight loss). The strong biodegradation of HHW was further demonstrated by characterisation by Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR). Characterisation by SEM showed that the surfaces of the biodegraded samples were eroded.
Extensive quantities of apple pomace are generated annually but its disposal is still challenging. This study addresses this issue by introducing a new, environmentally-friendly approach for the ...production of sustainable biomaterials from apple pomace, containing 55.47% free sugars and a water insoluble fraction, containing 29.42 ± 0.44% hemicelluloses, 38.99 ± 0.42% cellulose, and 22.94 ± 0.12% lignin. Solution casting and compression molding were applied to form bio-based films and 3D objects (i.e., fiberboards), respectively. Using glycerol as plasticizer resulted in highly compact films with high tensile strength and low elongation (16.49 ± 2.54 MPa and 10.78 ± 3.19%, respectively). In contrast, naturally occurring sugars in the apple pomace showed stronger plasticizing effect in the films and resulted in a fluffier and connected structure with significantly higher elongation (37.39 ± 10.38% and 55.41 ± 5.38%, respectively). Benefiting from the self-binding capacity of polysaccharides, fiberboards were prepared by compression molding at 100 °C using glycerol or naturally occurring sugars, such as plasticizer. The obtained fiberboards exhibited tensile strength of 3.02⁻5.79 MPa and elongation of 0.93%⁻1.56%. Possible applications for apple pomace biomaterials are edible/disposable tableware or food packaging.
The potential of two zygomycetes fungi, Mucor indicus and Rhizopus oryzae, in assimilating citrus waste free sugars (CWFS) and producing fungal chitosan, oil, and protein as well as ethanol was ...investigated. Extraction of free sugars from citrus waste can reduce its environmental impact by decreasing the possibility of wild microorganisms growth and formation of bad odors, a typical problem facing the citrus industries. A total sugar concentration of 25.1 g/L was obtained by water extraction of citrus waste at room temperature, used for fungal cultivation in shake flasks and airlift bioreactor with no additional nutrients. In shake flasks cultivations, the fungi were only able to assimilate glucose, while fructose remained almost intact. In contrast, the cultivation of M. indicus and R. oryzae in the four-liter airlift bioreactor resulted in the consumption of almost all sugars and production of 250 and 280 g fungal biomass per kg of consumed sugar, respectively. These biomasses correspondingly contained 40% and 51% protein and 9.8% and 4.4% oil. Furthermore, the fungal cell walls, obtained after removing the alkali soluble fraction of the fungi, contained 0.61 and 0.69 g chitin and chitosan per g of cell wall for M. indicus and R. oryzae, respectively. Moreover, the maximum ethanol yield of 36% and 18% was obtained from M. indicus and R. oryzae, respectively. Furthermore, that M. indicus grew as clump mycelia in the airlift bioreactor, while R. oryzae formed spherical suspended pellets, is a promising feature towards industrialization of the process.
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