With growing awareness of a circular economy, it is necessary to utilize all lignocellulose biomass components as a resource to maintain sustainability. We have selectively targeted the one-step ...conversion of hemicellulose in sugarcane bagasse to xylooligosaccharides (XOS), which are useful dietary supplements, while keeping the cellulose and lignin relatively intact. In addition to the circular economy and green processing chemistry, we pursue plasma treatment of carbon materials as a global effort to produce metal-free carbon-based catalysts. Herein, activated carbon (AC) was subjected to two different treatments: plasma irradiation to create a porous honeycomb structure and redistribute surface oxygenate functional groups (phenolics -OH), lactonics, and (-COOH) and acid impregnation with HNO
3
to enhance the overall acidic functional groups of the carbon, especially the -COOH groups. The functionalized AC was effective to selectively depolymerize sugarcane bagasse hemicellulose to XOS in water as a solvent. High XOS yields of 50.0% (composed of xylobiose (14.1%), xylotriose (11.9%), xylotetraose (8.8%), xylopentaose (9.1%) and xylohexaose (6.0%)), and 15% xylose were obtained. No undesirable sugar degradation products - furans - were detected. Thus, we propose that the tandem sequence of plasma and acid modification of AC is a facile one-step new method to depolymerize hemicellulose from lignocellulosic biomass.
Selective depolymerization of sugarcane bagasse to various xylose oligomers using a hybrid of plasma-acid treated activated carbon.
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•The two-step carbonization approach gave improved carbon properties of OTR.•KOH activation improved the properties of carbon from pyrolytic tyre solid residue.•Si, Zn, Fe and KCl are ...effectively recovered for reuse in industrial processes.•Recovered SiO2 has an exceptionally high cross-linking ratio.•Functionalized carbon can be used for energy storage and catalyst applications.
This study aims to identify suitable processing conditions for converting pyrolytic solid residue from off-the-road tyres (OTR) to improve carbon materials properties that can be used in multiple applications and the recovery of minerals from OTR. Pyrolysis of OTR at 800 °C and a heating rate 2 °C.min−1 gave a carbon material with the highest surface area, most defective carbon structures, and the highest micro-porosity. This operating condition was used to compare the conventional three-step carbonization approach, which involves a demineralization stage that produces high volumes of toxic wastewater, with a two-step approach that bypasses this stage. Analysis of the carbon structures showed that the quality of the carbon material from the two-step approach is similar to the three-step approach. This two-step approach resulted in a solid and a liquid phase, in which ∼ 93.4% of Zn was selectively fractionated to the liquid phase. The wastewater from the acid wash of the carbonized OTR was neutralized to recover the SiO2, of which 55.5% was reactive SiO2. The SiO2 was found to have an exceptionally high cross-linking ratio of 5.94, achievable only when SiO2 is reacted with silane groups. The study demonstrated that the engineered carbon material from OTR has a H2 uptake of 1.03 wt% at 77 K and 1.2 bar, and the sulfonated counterpart was an effective catalyst (64% conversion) for the Aldol condensation of levunilic acid to two dimer products tetrahydro-2- methyl-5,γ-dioxo-2-furanpentanoic acid (TMDFA) and 3-(2-methyl-5-oxo- tetrahydrofuran-2-yl)-4-oxopentanoic acid (MOTOA) that are precursors for fuels and chemicals.
A taxonomic and annotated functional description of microbial life was deduced from 53 Mb of metagenomic sequence retrieved from a planktonic fraction of the Neotropical high Andean (3,973 meters ...above sea level) acidic hot spring El Coquito (EC). A classification of unassembled metagenomic reads using different databases showed a high proportion of Gammaproteobacteria and Alphaproteobacteria (in total read affiliation), and through taxonomic affiliation of 16S rRNA gene fragments we observed the presence of Proteobacteria, micro-algae chloroplast and Firmicutes. Reads mapped against the genomes Acidiphilium cryptum JF-5, Legionella pneumophila str. Corby and Acidithiobacillus caldus revealed the presence of transposase-like sequences, potentially involved in horizontal gene transfer. Functional annotation and hierarchical comparison with different datasets obtained by pyrosequencing in different ecosystems showed that the microbial community also contained extensive DNA repair systems, possibly to cope with ultraviolet radiation at such high altitudes. Analysis of genes involved in the nitrogen cycle indicated the presence of dissimilatory nitrate reduction to N2 (narGHI, nirS, norBCDQ and nosZ), associated with Proteobacteria-like sequences. Genes involved in the sulfur cycle (cysDN, cysNC and aprA) indicated adenylsulfate and sulfite production that were affiliated to several bacterial species. In summary, metagenomic sequence data provided insight regarding the structure and possible functions of this hot spring microbial community, describing some groups potentially involved in the nitrogen and sulfur cycling in this environment.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•Cotton gin trash catalyst is effective in the dehydration of fructose to HMF.•Cotton gin trash catalyst consists of 3 aromatic layers, –COOH and –SO3H groups.•The reusability of ...cotton gin trash derived catalyst is >5 times.•Fructose was transformed via a carbaldehyde intermediate prior to dehydration.•Adsorption mechanism of catalyst goes by liquid film and intra-particle diffusions.
Biomass-derived carbon catalysts have been extensively studied for the dehydration of sugars to platform chemical 5-hydroxymethyl furfural (HMF), which can be used to produce valuable chemicals and fuels. However, only limited studies have been conducted to determine their carbon molecular structures and how these influence the conversion process. Here, we prepare a chlorosulfonated carbon catalyst derived from cotton gin trash (CGT) at 400 °C for the dehydration of fructose to produce 5-hydroxymethyl furfural (HMF) in the ionic liquid, 1-butyl-3-methyl-imidazolium chloride (BMIMCl). The highly efficient chlorosulfonated carbon catalyst consisting of 3 aromatic layers of furanic, phenolic rings and aliphatic–aromatic carbon structures with –COOH, phenolic OH, -SO3-, and -SO3H functional groups were found to have a similar performance as the commercial catalyst, Amberlyst-15. The carbon material was reused 5 times without loss of catalytic activity. The formation of the sugar intermediate, 3,4-dihydroxy-5-hydroxymethyl-tetrahydrofuran-2-carbaldehyde may be related to –COOH and phenolic OH groups forming hydrogen bonds with fructose, and the adsorption of fructose onto the graphitized sp2 internal carbon regions where interactions with the defects in the carbon material occur.
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•Hydrothermal liquefaction of sugarcane bagasse in ethanol improves bio-oil stability.•The aging process does not significantly affect HHVs of bio-oils.•Organic acids are breakdown ...products formed during aging.•Bio-oil derived from ethanol solvent gives >90% light oil.•Solvent extraction improves bio-oil thermal stability.
Bio-oil produced from the hydrothermal liquefaction (HTL) of biomass is unstable and cannot be transported over long distances to a refinery for upgrading to transportation fuel. This study examined the effect of the liquefaction solvent on the stability of bio-oils derived from the HTL of sugarcane bagasse. The accelerated aging test (0–8 days at 80 °C) was used to assess the stability of these oils with the aid of indicators such as water content, molecular weight range, functional groups present, phase separation, thermal stability, and the amount of residue after thermal analysis of the oils. The HTL solvent mixture of ethanol/water was found to produce the most stable bio-oil when compared to crude glycerol/water or water on its own. The light oils fractionated by solvent extraction were more stable than their corresponding bio-oils. The higher heating values (HHVs) of the light oils during the agiging process were relatively stable and were between 33 and 35 MJ/kg. The maximum boiling temperature of the first peak in the DTG thermogram of the aged light oil derived from ethanol/water is 147 °C (cf. diesel of 157 °C), while that of crude glycerol/water light oil is up to 190 °C. The stabilities of the oils derived from either ethanol or crude glycerol are related to alkylation, esterification, and acetalization reactions. This study has demonstrated that the HTL of sugarcane bagasse in the presence of ethanol/water produces oils of good quality that have long shelf-lives and have been projected to be stored for up to 8 years with minor compositional and structural changes.
Se evaluó el efecto de un agente anticoagulante del látex en el árbol de caucho (Hevea brasiliensis). Se caracterizó el contenido de solidos totales (TSC) y contenido de caucho seco (DRC) del látex, ...se evaluaron cuatro tratamientos de anticoagulantes en campo: (T1) amoniaco, (T2) bórax, (T3) amoniaco-bórax y (T0) sin anticoagulante. En las láminas se evaluaron cinco diluciones (v/v) de látex en agua D1 (100 %), D2 (75 %), D3 (50 %), D4 (25 %) y D5 (0 %), a estas se hicieron pruebas de tensión, compresión y espesor. El látex caracterizado obtuvo TSC (37.1 %+0.27), DRC (34.3 %+0.19). Encontrándose en T3D1 mayor resistencia de tensión hasta punto de ruptura de 13.37 KgF, compresión de 5 KgF, y menor espesor de 1.52 mm, sin diferencia significativa entre los tratamientos T3 y T2 y las diluciones D1 a D2, posibilitando reducir el consumo de agua (25 %), y la producción de ripio (38 %) con anticoagulantes, sin afectar negativamente sus propiedades mecánicas.
The objective of this research was the physicochemical characterization, fatty acid composition and Vitamin E content of oil extracted from the kernel of the fruit of cumare´s palm (Astrocaryum ...chambira). The plant material used in this research was collected in Caney-Restrepo, km 12 in the department of Meta-Colombia. The oil extraction process was performed by the soxhlet method using n-hexane as solvent, applying a unifactorial three-level experimental design to determine the most appropriate mass: solvent ratio. The percentage of lipids in dry basis of the kernel samples was 46.88 ± 0.73, which corresponds to the ratio 5 g of dry sample: 150 mL of solvent. The results of the physicochemical parameters were: density at 25 °C 0.9171 ± 0.003 g mL-1, refractive index at 40 °C 1.4518 ± 0.0004, iodine index 8.28 ± 0.60 g I2 100 g-1 oil, saponification index 246.66 ± 0.69 mg KOH g-1 oil, the percentage of acidity 0.248% ± 0.002 and the acid index 0.694 ± 0.006 mg KOH g-1 oil. The fatty acid profile presented a higher proportion of saturated (91.6%) than unsaturated (8.3%), likewise the analysis showed that lauric acid is the most abundant (48.6%) followed by myristic (29.8%), palmitic (6.7%), oleic (5.7%) and linoleic (2.5%). Based on the results obtained in the present study, data reported in the literature and regulations related to the use of oils of vegetable origin, this oil shows a great potential to be used as raw material in the food, pharmaceutical and oleochemical industry is feasible. However, it is recommended to perform additional tests in order to reaffirm their use in them.
La extracción de compuestos bioactivos de Pleurotus ostreatus por maceración dinámica, es un proceso sencillo y económico, que normalmente presenta baja eficiencia. El objetivo de este trabajo fue ...evaluar el proceso de extracción para determinar qué tratamiento permite la mayor eficiencia, analizando la influencia de los factores de estudio: concentración de etanol (50 %, 80 %, 95 %) y relación sólido/solvente (1:10, 1:20, 1:30). Se maceraron 5 g de polvo fúngico en etanol acuoso durante 90 minutos, a 150 rpm, 25 °C y tamaño de partícula de 0,5 a 1,0 mm. Se trataron los datos mediante estadística paramétrica con un nivel de confianza del 95 %. Los resultados revelaron que la mayor eficiencia de extracción total (40,9 %) en base seca se obtuvo con etanol al 50 % y una relación sólido/solvente de 1:30. Por componentes se encontró que, el etanol al 50 % con una relación de 1:20 permitió la máxima eficiencia para carbohidratos totales (17,9 %) y polisacáridos (17,2 %), mientras que con una relación de 1:30 se obtuvo la máxima eficiencia para azúcares reductores (0,91 %) y polifenoles (0,23 %). Por otro lado, el etanol al 95 % y la relación 1:30 permitió la máxima eficiencia para proteínas (29,4 %). La extracción de beta-glucanos no fue significativa. La eficiencia de la extracción está muy influenciada por los parámetros de operación, principalmente por la concentración de etanol; en particular, la de 50 % resultó más favorable para la obtención de la mayoría de sustancias bioactivas con potencial nutracéutico.
This study investigates the morphological and functional differences between the char produced after pyrolysis and hydrothermal liquefaction (HTL) of sugarcane bagasse termed pyrochar and hydrochar, ...respectively. The char materials were activated with KOH at 800 °C and doped with SnCl2·2H2O salt to produce an environmentally friendly catalyst (i.e., SnO x -char) to be further evaluated as a catalyst for glucose conversion in ethanol media. Activation increased the surface area and microporosity development of the chars, thus enabling more effective tin doping. Hydrochar had a lower surface area with no micropore development but exhibited more carbonyl functional groups on the surface of up to 65% content compared to pyrochar. The pyrochar showed superior catalytic performance because of the higher tin doping and more pronounced microporous carbon structure. Effects of glucose ratio (1:1–1:10), reaction temperature (140–220 °C), and time (1–8 h) on the production of 5-methyl furfural (MF) from glucose using pyrochar were systematically explored. This work achieved over 32.8% MF yield at 200 °C after 8 h of processing catalyzed by the tin-doped pyrochar in ethanol. It is demonstrated that the char produced by pyrolysis and HTL differs in its characteristics and catalytic activity performance, with the pyrochar being more suitable for the one-step catalytic conversion of glucose into MF.
La presente investigación tuvo como propósito evaluar el rendimiento y las características de la pectina extraída enzimáticamente a partir de la cáscara, pericarpio del fruto de cacao (Theobroma ...cacao L.); para ello, se realizó un diseño de tipo unifactorial, con 4 niveles de tratamiento, variando la concentración de complejo enzimático comercial Viscozyme L., de la marca Novozyme®. La pectina obtenida fue caracterizada, de acuerdo a la metodología planteada por Owens et al. 1952. Se elaboró un producto comercial tipo conserva (mermelada), donde se comparó la pectina obtenida enzimáticamente, con pectina comercial de alto y bajo metoxilo; en ambos casos fue evaluada la viscosidad aparente del fluido obtenido. Como resultados, se obtuvo mayor rendimiento de extracción de pectina promedio (13,0±0,53%), utilizando la mayor concentración de complejo enzimático (82,9 µL/100g cáscara), presentando diferencias significativas con los demás tratamientos (p<0,05); el porcentaje de metóxilo (ME) fue de 1,58±0,01%, el peso equivalente (PE) 5091,4±77,6 mg/meq; la acidez libre (AL) 0,20±0,01meq/g; el grado de esterificación (GE) 72±0,1% y el porcentaje de ácido anhídridogalacturónico (AAG) 12,5±1,0%. Con respecto al producto comercial, se observaron características reológicas de un fluido no Newtoniano pseudoplástico, con una viscosidad aparente máxima de 6043,7 mPa.s y mínima de 1741,3 mPa.s, al aumentar la fuerza del torque, presentando una menor capacidad viscosante que la pectina comercial. De acuerdo a los resultados obtenidos, se demostró que existe la oportunidad de obtener pectinas a partir de residuos del sector cacaotero, utilizando enzimas comerciales, con posibles usos en la industria alimentaria.
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