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Recovery of essential oils, polyphenols, fermentable sugars, and pectin from orange residues: Evaluation of extraction methodologies and characterization of value-added bioactive compounds
No full textResidues from orange processing are being continuously generated in vast amounts due to the increasing demand for this fruit and its byproducts worldwide. The valorization of Orange Residues is challenging in contrast to conventional “lignocellulosic residues” since this fruit-derived biomass contains high amounts of pectin and an extractive fraction rich in sugars, essential oils, and polyphenols. The relative amounts of these fractions are highly influenced by the juice/pulp extraction process. Even though several studies have explored how to produce added value from this biomass, it is necessary to compare how different techniques and operating conditions influence the bioactive compounds that can be recovered and the remnant biomass after processing. This study compares essential oil extraction, solvent extraction, and acid hydrolysis for fermentable sugar and pectin production to elucidate a feasible sequence for a biorefinery from Orange Residues. From our results, it was proposed a technically feasible sequence that maximizes the yields of i) essential oils (0.70 ± 0.05 g/ 100 g DM) from steam distillation (4 h, 1500 W), ii) naringin (0.19 g/100 g DM), hesperidin (1.27 g/100 g DM), and glucose (3.9 g/100 g DM) from solid-liquid extraction (Ethanol 61.6 % (w/v), 45.8 °C, 155.5 min, and 5 % (w/v) biomass load), iii) pectin (25.24 g/100 g DM) from citric acid hydrolysis (pH 1.5, 90 °C, 82.1 min, and 5 % (w/v) biomass load), and iv) glucose (12.41 g/100 g DM) and xylose (10.13 g/100 g DM) from sulfuric acid hydrolysis (Sulfuric acid 0.68 % (w/v), 121 °C, 24.1 min, and 7.32 % (w/v) biomass load), in a biorefinery scheme
Fate of phosphorus and potassium in gasification of wheat bran and sunflower seed shells
No full textThermal conversion of agricultural biomass residues poses a great opportunity to valorize waste materials by recovering energy and valuable elements such as phosphorus. Utilizing biomass residues in thermal conversion is, on the other hand, often coupled with operational challenges due to particle emissions, deposit formation, corrosion and slagging caused by the ash-forming elements in the biomass. A detailed understanding of the ash chemistry is required when utilizing those fuels to reduce these operational problems and recover valuable elements from the ash. However, predictions for ash transformation are often always reliable when using existing thermodynamic data and ash transformation mechanisms. The present work investigated the release of phosphorus and potassium during gasification of two seed-originated agricultural biomass residues, wheat bran and sunflower seed shells, at 900–1100 °C in 3 % O2 or 10 % CO2 (rest N2). The residues were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and inductively coupled plasma optical emission spectroscopy (ICP-OES). During the gasification of wheat bran, phosphorus and potassium were partly released to the gas phase, while only potassium was released to the gas phase during the gasification of sunflower seed shells. The residues from the gasification of wheat bran contained mainly K-Mg-phosphates, while phosphorus was identified as hydroxyapatite in the sunflower seed shell residues. The experimental observations for wheat bran are in contradiction with predictions from thermodynamic equilibrium calculations, which suggest that all phosphorus remains in the residues. The discrepancy between the experimental and calculated results may be due to carbothermic reduction of phosphates, i.e. reactions between phosphates and carbon. As the occurrence of carbothermic reduction reactions is connected to the kinetics of the carbon consumption, it is suggested that thermodynamic data alone is not sufficient to correctly predict the ash chemistry in thermal conversion processes of phosphorus rich biomass fuels
Using Enzymes for Catalysis under Industrial Conditions
No full textUsing enzymes for the catalysis of synthetically interesting chemical reactions enables high selectivity under mild conditions. However, for biocatalysis to be viable in an industrial context, reaction performance metrics must meet certain values to ensure cost-effectiveness, especially for the production of lower priced products. In industrial reactors, enzymes must function under conditions that are quite different from those in nature. Industrial reactors often involve not only high concentrations of substrates and products but also concentration gradients as well as gas–liquid interfaces. Conventionally, enzymology has primarily focused on understanding enzymes under a limited range of conditions such as temperature and pH, but there is now a pressing need to develop a new branch of enzymology tailored to industrially relevant environments. Achieving this will require the development of a novel scale-down apparatus that can replicate industrial conditions within a laboratory setting as well as new standardized screening models to discover enzymes that can perform well under such conditions
Heart rate variability is not associated with multiple chemical sensitivity in a cross-sectional population-based study - The Danish study of functional disorders
No full textObjective: Multiple chemical sensitivity (MCS), a functional somatic disorder (FSD), is a multisystem, polysymptomatic disease, characterized by various individual symptoms attributed to low level of volatile chemical exposures. Symptoms relate to the autonomic nerve system (ANS) among others which is mandatory in the MCS delimitations. An accepted measure of ANS is heart rate variability (HRV). The aim was to explore associations between HRV and MCS in the general Danish population. Methods: In the Danish Study of Functional Disorders, 7493 adults filled in questionnaires and participated in a physical health examination (2012-2015). The "E motion" heart rate monitor device assessed time and frequency measures of HRV. For this study, 143 were categorized with MCS of which, 84 were subcategorized as MCS without comorbid FSD. The remaining population (n = 5525) was used as comparison group. Logistic regression models to assess odds ratio (OR) with 95 % confidence intervals (95 % CI) of MCS, and MCS without comorbid FSD for each HRV exposure adjusted for age, sex, and chronic stress. Results: Compared to the general population, median resting heart rate was higher (64.7 vs 63.1 bpm, p = 0.007) and median normal-to-normal intervals was lower (930 vs 952 ms, p = 0.007) in MCS individuals. Resting heart rate was associated with MCS (OR: 1.019, 95 %CI: 1.003; 1.037); but not after adjustment for chronic stress. No other associations with other HRV measures nor in MCS without comorbid FSD were found. Conclusions: HRV was not associated with MCS. The magnitude of the differences between groups was small and of uncertain clinical significance
Impact of operational losses on the levelized costs of energy and in the economic viability of offshore wind power projects
No full textOffshore wind power offers a viable solution to the challenge of reducing fossil fuel dependency. However, certain offshore wind projects encounter challenges in meeting expected returns, particularly over the medium to long term. This study addresses the discrepancy between assumed and actual cost behaviors in techno-economic assessments of wind farm projects. The present study evaluates their impact of operational loss trends (e.g. increased failure rates, aging, potential curtailment) on project viability through a comprehensive techno-economic assessment. To this end, key metrics including Net Present Value and Levelized Cost of Energy, complemented by stochastic analyzes are explored through Monte Carlo Simulation and sensitivity analysis. Results indicate that costs may exceed those of the reference scenario by up to 21.6% in the worst-case scenario, highlighting the critical need for proactive monitoring and management of operational losses
Physicochemical properties of short-side-chain perfluorosulfonic acid membranes at elevated temperatures
No full textWater and CO2 electrolysis at elevated temperatures in cells equipped with short-side-chain perfluorosulfonic acid membranes could potentially allow for new approaches to tuning catalyst kinetics and selectivity, but the membrane characteristics under such conditions remains to be described. In this work, a short-side-chain perfluorosulfonic acid membrane (Aquivion) is characterized at temperatures up to 150 °C and high humidification levels with respect to tensile behavior, ionic conductivity, permeability of hydrogen and methanol, and stability. The membrane is found to retain mechanical robustness at temperatures up to at least 130 °C while dehydration at temperatures above 100 °C under ambient pressure results in a significant conductivity decay. The densification of the membrane matrix at temperatures above the boiling point of water under varied pressures leads to reduced hydrogen and methanol permeability. Pressurization up to 5 bars effectively mitigates the conductivity decay due to the presence of liquid water but also results in increased permeability. The membrane stability test, as characterized by hydrogen crossover measurements, shows that humidification is a harsher stressor than temperature in the studied range
A non-target evaluation of drinking water contaminants in pilot scale activated carbon and anion exchange resin treatments
No full textThis study evaluates the effectiveness of five types of Granular Activated Carbon (GAC) and one anion exchange resin in a pilot plant for treating groundwater for drinking water production, specifically targeting the removal of persistent compounds like PFAS. Using liquid chromatography and supercritical fluid chromatography coupled with high-resolution mass spectrometry, hundreds of features (i.e. peak at specific mass and retention time) were detected in the groundwater by non-target analysis. Initially, after treating <3200 bed volumes (BV), the GAC filter materials showed < 6 % breakthrough for all features from the groundwater, with decreasing efficiency down to 79 % breakthrough after seven month (69,000 treated BV for μGAC). Using resin as a lag filter after GAC did not improve the removal of compounds detected in positive electrospray ionization mode. However, it enhanced removal by up to 35% for compounds detected in negative electrospray ionization mode, indicating higher selectivity of resin for acidic compounds like PFAS. The shortest detected PFAS (PFBA and PFPeA) broke through completely for all GAC and the resin material except the proprietary blended GAC (at 15,700 treated BV), which had only 19% breakthrough for PFPeA. The so far rarely detected perfluoro(4-ethylcyclohexane) sulfonic acid (PFECHS) was well adsorbed by GAC coupled to resin and by the proprietary blended GAC. Pesticides were effectively removed by GACs, but not by the resin filter. Contaminants not previously detected in groundwater, 2,4,5-trichlorobenzenesulfonic acid (TCBS) and 2-amino-4-chloro-5-methylbenzenesulfonic acid (ACMBS), were effectively removed (>92 %), but high ACMBS concentrations (360 ng/L) in groundwater are of concern. The drinking water after the resin filter revealed 20 new contaminants, such as tributylamine derivatives and monobutyl phthalate, indicating resin filters contribution to drinking water contamination. Accelerated migration experiments of the resin revealed additional contaminants, such as NDBA and further phthalates, highlighting the need for continued monitoring and evaluation of resin materials in water treatment systems
Effect of post-chilling processes and modified atmosphere packing on <i>Campylobacter </i>in broiler meat
No full textCampylobacter infections, predominantly attributed to C. jejuni and C. coli, are a prominent cause of foodborne illness on a global scale, specifically associated with the ingestion of chicken meat. Effective control techniques against Campylobacter are increasingly important with the growing global demand for chicken. The effects of control measures can be evaluated by quantitative microbial risk assessment (QMRA) models, and for these models, it is important to know the reduction. In this context, this study aimed to investigate the degree of reduction of Campylobacter concentrations from neck skin to meat post-chilling and to assess the impact of modified atmosphere packaging (MAP) on these concentrations. Samples were collected from a Danish commercial broiler slaughterhouse processing approximately 172,000 broilers daily. Three Campylobacter-positive flocks were identified and sampled. For each flock, 30 broiler carcasses were randomly selected post-chilling and their neck skins were sampled (NS). Half of them (n = 15) were packaged as a whole chicken in MAP consisting of 80% O2 and 20% CO2 and neck skins were collected after 7 days (NS-M). For the other half, the skin of the breast was removed aseptically, and breast meat was sampled after 5 min (BF). Twelve machine-cut breast fillets originating from the same flock were randomly sampled later in the processing line and packed individually in MAP (BF-M). Additionally, the Campylobacter isolates were frozen and subsequently whole-genome-sequenced (WGS) to assess if certain sequence types were more tolerant to post-chilling processes. The results showed that removing the skin (NS vs. BF) reduced Campylobacter concentrations by 2.22 log10. The MAP reduced Campylobacter concentrations by 0.74 log10 (NS vs. NS-M). Genetic analysis of 82 Campylobacter isolates identified sequence types ST 2274 in C. jejuni and ST 832, ST 1109, and ST 12012 in C. coli. The findings suggest that the degree of Campylobacter reduction from skin to meat is higher than previously estimated, indicating a potentially lower consumer risk. These insights can enhance the accuracy of QMRA models, informing interventions to reduce Campylobacter contamination in the broiler production chain
The paddlewheel complex of 1,8-naphthyridine and palladium(II)
No full textThis work presents the synthesis of the tetracationic paddlewheel complex of 1,8-naphthyridine and palladium(II), [Pd2(µ-napy)4]X4, (X = BF4− or PF6−). Single-crystal X-ray diffraction confirms a D4h symmetric paddlewheel structure encompassing the two Pd units in the metal core coordinated by four ditopic 1,8-naphthyridine ligands, featuring a relatively short Pd–Pd distance. Spectroscopic analyses combined with density-functional theory (DFT) provide insights into the nature of the Pd–Pd and Pd–Napy interactions as well as observed optical absorption frequencies.</p
Use of Benzyl Alcohol as a Solvent for Kraft Lignin
No full textLignin, an abundant and complex aromatic biopolymer, holds significant potential for producing value-added chemicals and materials. However, its utilization is limited by its solubility in common organic solvents. In this study, we investigated the solubility of softwood Kraft lignin in benzyl alcohol and compared it to other traditionally studied solvents. Methanol achieved a lignin solubility yield of 59%, while ethanol (18%) and acetone (34%), due to their longer alkyl chains and lower polarity, were less effective in solubilizing larger lignin fragments. Benzyl alcohol, on the other hand, exhibited a complete dissolution of lignin, thereby exceeding by far the capability of the standard solvents. Furthermore, benzyl alcohol resulted in a moderate molecular weight of 3621 g/mol for the lignin fragments and a narrow polydispersity index of 1.54. The complete solubility of lignin in benzyl alcohol suggests significant potential for high yield lignin fractionation and subsequent chemical modifications, which are essential for valorization. Despite the high boiling point of benzyl alcohol, the enhanced solubility could facilitate the production of homogeneous lignin fractions with increased reactive sites, thereby broadening the scope of lignin applications in coatings and industrial materials. Complete lignin solubility in benzyl alcohol could serve as an efficient solvent for end-product applications