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Imines or Schiff bases (SB) are formed by the condensation of an aldehyde or a ketone with a primary amine, with the removal of a water molecule. Schiff bases are central molecules in several biological processes for their ability to form and cleave by small variation of the medium. We report here the controlled hydrolysis of four SBs that may be applied in the fragrance industry, as they are profragrances all containing odorant molecules: methyl anthranilate as primary amine, and four aldehydes (cyclamal, helional, hydroxycitronellal and triplal) that are very volatile odorants. The SB stability was assessed over time by HPLC-MS in neutral or acidic conditions, both in solution and when trapped in low molecular weight gels. Our results demonstrate that it is possible to control the hydrolysis of the Schiff bases in the gel environment, thus tuning the quantity of aldehyde released and the persistency of the fragrance.

The reaction mechanism of glycoside hydrolases belonging to family 1 (GH1) of carbohydrate-active enzymes classification, hydrolysing β-O-glycosidic bonds, is well characterised. This family includes several thousands of enzymes with more than 20 different EC numbers depending on the sugar glycone recognised as substrate. Most GH1 β-glycosidases bind their substrates with similar specificity through invariant amino acid residues. Despite extensive studies, the clear identification of the roles played by each of these residues in the recognition of different glycones is not always possible. We demonstrated here that a histidine residue, completely conserved in the active site of the enzymes of this family, interacts with the C2-OH of the substrate in addition to the C3-OH as previously shown by 3 D-structure determination.

In the field of biocatalysis and the development of a bio-based economy, hemicellulases have attracted great interest for various applications in industrial processes. However, the study of the catalytic activity of the lignocellulose-degrading enzymes needs to be improved to achieve the efficient hydrolysis of plant biomasses. In this framework, hemicellulases from hyperthermophilic archaea show interesting features as biocatalysts and provide many advantages in industrial applications thanks to their stability in the harsh conditions encountered during the pretreatment process. However, the hemicellulases from archaea are less studied compared to their bacterial counterpart, and the activity of most of them has been barely tested on natural substrates. Here, we investigated the hydrolysis of xyloglucan oligosaccharides from two different plants by using, both synergistically and individually, three glycoside hydrolases from Saccharolobus solfataricus: a GH1 β-gluco-/β-galactosidase, a α-fucosidase belonging to GH29, and a α-xylosidase from GH31. The results showed that the three enzymes were able to release monosaccharides from xyloglucan oligosaccharides after incubation at 65 °C. The concerted actions of β-gluco-/β-galactosidase and the α-xylosidase on both xyloglucan oligosaccharides have been observed, while the α-fucosidase was capable of releasing all α-linked fucose units from xyloglucan from apple pomace, representing the first GH29 enzyme belonging to subfamily A that is active on xyloglucan.

The present study describes the first example of utilization of a natural clay mineral as catalyst in a process addressed to chemical valorization of poly-[bisphenol A carbonate] (PC; (1)) wastes. A natural clinochlore was investigated for the first time as the catalyst of the hydrolysis reaction of 1, a potential route to chemical recycling of wastes of this polymeric material. At 473 K, in tetrahydrofuran (THF) as the solvent, the mineral promoted effectively the depolymerization (up to 99%, after 6 h) of 1 by H2O and the selective (~99%) regeneration of the monomer bisphenol A (BPA, (2)). Temperature, catalyst loading, reaction time, H2O/PC weight ratio affected markedly the productivity of the process. The role of the catalyst was also focused: the experimental data showed that the exposed brucite-like sheets of clinochlore are involved in the hydrolysis reaction and take active part in promoting the depolymerization process.

In order to calibrate the model parameters, Sensitivity Analysis routines are mandatory to rank the parameters by their relevance and fix to nominal values the least influential factors. Despite the high number of works based on ADM1, very few are related to sensitivity analysis. In this study Global Sensitivity Analysis (GSA) and Uncertainty Quantification (UQ) for an ADM1-based Anaerobic Digestion Model have been performed. The modified version of ADM-based model selected in this study was presented by Esposito and co-authors in 2013. Unlike the first version of ADM1, focused on sewage sludge degradation, the model of Esposito is focused on organic fraction of municipal solid waste digestion. It his recalled that in many applications the hydrolysis is considered the bottleneck of the overall anaerobic digestion process when the input substrate is constituted of complex organic matter. In Esposito's model a surfaced based kinetic approach for the disintegration of complex organic matter is introduced. This approach allows to better model the disintegration step taking into account the effect of particle size distribution on the digestion process. This model needs thus GSA and UQ to pave the way for further improvements and reach a deep understanding of the main processes and leading input factors. Due to the large number of parameters to be analyzed a first preliminary screening analysis, with the Morris' Method, has been conducted. Since two quantities of interest (QoI) have been considered, the initial screening has been performed twice, obtaining two set of parameters containing the most influential factors in determining the value of each QoI. A surrogate of ADM1 model has been defined making use of the two defined quantities of interest. The output results from the surrogate model have been analyzed with Sobol' indices for the quantitative GSA. Finally, uncertainty quantification has been performed. By adopting kernel smoothing techniques, the Probability Density Functions of each quantity of interest have been defined.

The use of cosolvents and high hydrostatic pressure (HHP) has been described as an efficient means to modulate the stability of enzymes and their catalytic activity. Cosolvents and pressure can lead to increased reaction rates without affecting the stability of the enzyme. Here, we studied the combined effects of one of the most used organic cosolvents, dimethyl sulfoxide (DMSO), and HHP to reveal their combined effect on the kinetic constants of an α-chymotrypsin-catalyzed peptide hydrolysis reaction. The Michaelis constant and the turnover number of the reaction respond differently to the two variables, and we observed an opposite effect of hydrostatic pressure and the dipolar cosolvent DMSO on the kinetic parameters. The results could be rationalized by determining the volume diagram of the reaction at the different solution conditions. In our case, the use of high hydrostatic pressure in concert with DMSO does not lead to an improvement of the enzymatic activity. However, the advantages of DMSO and HHP to increase the temperature stability of the enzyme and to increase the solubility of more hydrophobic substrates could still be useful.

Eucalyptus nitens wood samples were subjected to consecutive stages of hydrothermal processing for hemicellulose solubilization and delignification with an ionic liquid, i.e., either 1-butyl-3-methylimidazolium hydrogen sulfate or triethylammonium hydrogen sulfate. Delignification experiments were carried out a 170 C for 10&ndash, 50 min. The solid phases from treatments, i.e., cellulose-enriched solids, were recovered by centrifugation, and lignin was separated from the ionic liquid by water precipitation. The best delignification conditions were identified on the basis of the results determined for delignification percentage, lignin recovery yield, and cellulose recovery in solid phase. The lignins obtained under selected conditions were characterized in deep by 31P-NMR, 13C-NMR, HSQC, and gel permeation chromatography. The major structural features of the lignins were discussed in comparison with the results determined for a model Ionosolv lignin.

Enzymes of the 5' structure-specific nuclease family are crucial for DNA repair, replication, and recombination. One such enzyme is the human exonuclease 1 (hExo1) metalloenzyme, which cleaves DNA strands, acting primarily as a processive 5'-3' exonuclease and secondarily as a 5'-flap endonuclease. Recently, in crystallo reaction intermediates have elucidated how hExo1 exerts hydrolysis of DNA phosphodiester bonds. These hExo1 structures show a third metal ion intermittently bound close to the two-metal-ion active site, to which recessed ends or 5'-flap substrates bind. Evidence of this third ion has been observed in several nucleic-acid-processing metalloenzymes. However, there is still debate over what triggers the (un)binding of this transient third ion during catalysis and whether this ion has a catalytic function. Using extended molecular dynamics and enhanced sampling free-energy simulations, we observed that the carboxyl side chain of Glu89 (located along the arch motif in hExo1) flips frequently from the reactant state to the product state. The conformational flipping of Glu89 allows one metal ion to be recruited from the bulk and promptly positioned near the catalytic center. This is in line with the structural evidence. Additionally, our simulations show that the third metal ion assists the departure, through the mobile arch, of the nucleotide monophosphate product from the catalytic site. Structural comparisons of nuclease enzymes suggest that this Glu(Asp)-mediated mechanism for third ion recruitment and nucleic acid hydrolysis may be shared by other 5' structure-specific nucleases.

Host defence peptides (HDPs) are powerful modulators of cellular responses to various types of insults caused by pathogen agents. To date, a wide range of HDPs, from species of different kingdoms including bacteria, plant and animal with extreme diversity in structure and biological activity, have been described. Apart from a limited number of peptides ribosomally synthesized, a large number of promising and multifunctional HDPs have been identified within protein precursors, with properties not necessarily related to innate immunity, consolidating the fascinating hypothesis that proteins have a second or even multiple biological mission in the form of one or more bio-active peptides. Among these precursors, enzymes constitute certainly an interesting group, because most of them are mainly globular and characterized by a fine specific internal structure closely related to their catalytic properties and also because they are yet little considered as potential HDP releasing proteins. In this regard, the main aim of the present review is to describe a panel of HDPs, identified in all canonical classes of enzymes, and to provide a detailed description on hydrolases and their corresponding HDPs, as there seems to exist a striking link between these structurally sophisticated catalysts and their high content in cationic and amphipathic cryptic peptides.

In this work, natural phenolic compounds, such as Vanillic Acid (VA), Ferulic Acid (FA) and Thymol (Th), at very high concentrations, have been considered as pro-oxidant agents for Polylactic acid (PLA). Specifically, thin films of neat PLA and PLA-based systems containing 2 and 3 wt% of VA, FA and Th have been produced and subjected to accelerated degradation in different environmental conditions. Preliminary characterizations, through rheological, mechanical, optical and morphological analysis, of the formulated PLA-based systems show that the VA and FA, even less the Th, are able to exert a plasticizing action during the processing and subsequently, the PLA crystallinity and rigidity slightly decrease, while, the PLA ductility increase and its optical performance and morphology remain almost unchanged. To assess the pro-oxidant activity of the considered natural phenolic compounds, thin films of PLA and PLA-based systems containing VA, FA and Th have been subjected to accelerated degradation in different environmental conditions: (i) water-medium hydrolysis, (ii) photo-oxidation upon UVB exposure and (iii) thermo-oxidation upon thermal treatment in oven. All obtained results pointing out that the considered natural compounds, at these high concentrations, exert a clear pro-oxidant activity in PLA during the water-medium hydrolysis and the photo- and thermo-oxidative degradation. Moreover, the VA, FA and Th can be considered as suitable pro-degradant additives for PLA, also in order to control the bio-polyester degradation times.

We report the first histidine-containing self-assembling tripeptide devoid of capping groups that forms a thermoreversible hydrogel under physiological conditions and catalyses hydrolysis of an ester, providing a minimalist building block for functional soft materials.

Urease uses a cluster of two NiII ions to activate a water molecule for urea hydrolysis. The key to this unsurpassed enzyme is a change in the conformation of a flexible structural motif, the mobile flap, which must be able to move from an open to a closed conformation to stabilize the chelating interaction of urea with the NiII cluster. This conformational change brings the imidazole side chain functionality of a critical histidine residue, αHis323, in close proximity to the site that holds the transition state structure of the reaction, facilitating its evolution to the products. Herein, we describe the influence of the solution pH in modulating the conformation of the mobile flap. High-resolution crystal structures of urease inhibited in the presence of N-(n-butyl)phosphoric triamide (NBPTO) at pH 6.5 and pH 7.5 are described and compared to the analogous structure obtained at pH 7.0. The kinetics of urease in the absence and presence of NBPTO are investigated by a calorimetric assay in the pH 6.0-8.0 range. The results indicate that pH modulates the protonation state of αHis323, which was revealed to have pKa =6.6, and consequently the conformation of the mobile flap. Two additional residues (αAsp224 and αArg339) are shown to be key factors for the conformational change. The role of pH in modulating the catalysis of urea hydrolysis is clarified through the molecular and structural details of the interplay between protein conformation and solution acidity in the paradigmatic case of a metalloenzyme.

Dicalcium phosphate dihydrate (DCPD) is one of the mineral phases indicated as possible precursors of biological apatites and it is widely employed in the preparation of calcium phosphate bone cements. Herein, we investigated the possibility to functionalize DCPD with aspartic acid (ASP) and poly-aspartic acid (PASP), as models of the acidic macromolecules of biomineralized tissues, and studied their influence on DCPD hydrolysis. To this aim, the synthesis of DCPD was performed in aqueous solution in the presence of increasing concentrations of PASP and ASP, whereas the hydrolysis reaction was carried out in physiological solution up to three days. The results indicate that it is possible to prepare DCPD functionalized with PASP up to a polyelectrolyte content of about 2.3 wt%. The increase of PASP content induces crystal aggregation, reduction of the yield of the reaction and of the thermal stability of the synthesized DCPD. Moreover, DCPD samples functionalized with PASP display a slower hydrolysis than pure DCPD. On the other hand, in the explored range of concentrations (up to 10 mM) ASP is not incorporated into DCPD and does not influence its crystallization nor its hydrolysis. At variance, when present in the hydrolysis solution, ASP, and even more PASP, delays the conversion into the more stable phases, octacalcium phosphate and/or hydroxyapatite. The greater influence of PASP on the synthesis and hydrolysis of DCPD can be ascribed to the cooperative action of the carboxylate groups and to its good fit with DCPD structure.

Bee pollen is an attractive resource in the field of alternative remedies and thanks to the content of carbohydrates, crude fibers, proteins and lipids must be considered as a supplementary food of high potential rate. In characterization of bee pollen with the aim to define its value in human nutrition, the amino acids profile is one of the most important attributes. In the present study, the determination of amino acids composition of different monofloral bee pollen samples was obtained by an approach combining microwave acidic hydrolysis (60 min at 150 °C instead of 22 h at 120 °C in conventional oven) followed by derivatization using 9-fluorenylmethylchloroformate (FMOC-Cl) and separation of amino acids derivatives using a Phenomenex Kinetex core-shell 5 μm C18 (150 x 4.6 mm i.d.) column under a ternary gradient elution. Separation of 19 amino acids was achieved in about 40 min and fluorimetric detection (λexc = 265 nm λem = 315 nm) allowed selective and sensitive quantitation with LOQ values ranging within 0.14–3.00 μg/mL. Interestingly, the present approach allowed determination of some amino acids e.g., tryptophan and trans-4-hydroxyproline that are often lost by other methods of analysis. Significant differences in the composition of the considered samples were found confirming the impact of botanical origin of the product on its nutritional value. Principal Component Analysis was applied to treat the obtained data, highlighting the importance for discrimination, of detecting low abundance amino acids. The proposed method can be used as an advantageous alternative to the existing ones for characterization of bee pollen as an important source of dietary proteins.

The molecular identity of the mitochondrial megachannel (MMC)/permeability transition pore (PTP), a key effector of cell death, remains controversial. By combining highly purified, fully active bovine F-ATP synthase with preformed liposomes we show that Ca2+ dissipates the H+ gradient generated by ATP hydrolysis. After incorporation of the same preparation into planar lipid bilayers Ca2+ elicits currents matching those of the MMC/PTP. Currents were fully reversible, were stabilized by benzodiazepine 423, a ligand of the OSCP subunit of F-ATP synthase that activates the MMC/PTP, and were inhibited by Mg2+ and adenine nucleotides, which also inhibit the PTP. Channel activity was insensitive to inhibitors of the adenine nucleotide translocase (ANT) and of the voltage-dependent anion channel (VDAC). Native gel-purified oligomers and dimers, but not monomers, gave rise to channel activity. These findings resolve the long-standing mystery of the MMC/PTP and demonstrate that Ca2+ can transform the energy-conserving F-ATP synthase into an energy-dissipating device.

This work reports the demineralisation of soluble biorganic hyrolysates (SBOs) obtained from three materials sampled from a municipal biowaste treatment plant. The SBOs contain mineral and organic matter. They are promising bio‐based multipurpose products due to their properties as biosurfactants, chemicals for the manufacture of plastics, and fertilizers for plant growth. Demineralisation of SBOs was carried out by HCl ion exchange and HF washing to assess its effect on the pristine product chemical composition and properties. The demineralized products (SBOs‐DM) were characterized by elemental analysis, potentiometric titration, 13C‐NMR spectroscopy and surface tension measurements. They were compared with pristine SBOs. The following results were obtained: ash content 0.2‐1.1% in SBOs‐DM vs. 15–28% in pristine SBOs; lower aliphatic/aromatic C ratio in SBOs‐DM (0.8‐2.0) than in pristine SBOs (1.3‐3.4); higher critical (mineral free) micellar concentration for SBOs‐DM (1‐2.7 g L−1) than for pristine SBOs (1‐2.3 g L−1). The potential applications of SBOs‐DM and pristine SBOs are discussed.

An ongoing challenge in olive oil analytics is the development of a reliable procedure that can draw the consensus of all interested parties regarding the quantification of concentrations above the required minimum value of 5 mg of bioactive “olive oil polyphenols” per 20 g of the oil, to fulfill the health claim introduced by the European Commission (EC) Regulation 432/2012. An in-house validated ultra-high performance liquid chromatography (UHPLC) protocol fit for this purpose is proposed. It relies on quantification of the total hydroxytyrsol (Htyr) and tyrosol (Tyr) content in the virgin olive oil (VOO) polar fraction (PF) before and after acidic hydrolysis of their bound forms. PF extraction and hydrolysis conditions were as previously reported. The chromatographic run lasts ~1/3 of the time needed under high performance liquid chromatography (HPLC) conditions, this was also examined. Eluent consumption for the same piece of information was 6-fold less. Apart from being cost effective, a larger number of samples can be analyzed daily with less environmental impact. Two external curves, detection at 280 nm and correction factors for molecular weight difference are proposed. The method, which is fit for purpose, is selective, robust with satisfactory precision (percentage relative standard deviation (%RSD) values < 11%) and recoveries higher than 87.6% for the target analytes (Htyr, Tyr). Standard operational procedures are easy to apply in the olive oil sector., This work was developed in the context of the project OLEUM ‘Advanced solutions for assuring authenticity and quality of olive oil at global scale’ funded by the European Commission within the Horizon 2020 Programme (2014–2020, grant agreement [no. 635690]). The information and views set out in this article are those of the author(s) and do not necessarily reflect the official opinion of the European Union. Neither the European Union institutions and bodies nor any person acting on their behalf may be held responsible for the use which may be made of the information contained therein., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

Food and feed safety are of paramount relevance in everyday life. The awareness that different chemicals, e.g., those largely used in agriculture, could present both environmental problems and health hazards, has led to a large limitation of their use. Chemicals were also the main tool in a control of fungal pathogens and their secondary metabolites, mycotoxins. There is a drive to develop more environmentally friendly, “green”, approaches to control mycotoxin contamination of foodstuffs. Different mushroom metabolites showed the potential to act as control agents against mycotoxin production. The use of a polysaccharide, Tramesan, extracted from the basidiomycete Trametes versicolor, for controlling biosynthesis of aflatoxin B1 and ochratoxin A, has been previously discussed. In this study, oligosaccharides obtained from Tramesan were evaluated. The purified exopolysaccharide of T. versicolor was partially hydrolyzed and separated by chromatography into fractions from disaccharides to heptasaccharides. Each fraction was individually tested for mycotoxin inhibition in A. flavus and A. carbonarius. Fragments smaller than seven units showed no significant effect on mycotoxin inhibition, heptasaccharides showed inhibitory activity of up to 90% in both fungi. These results indicated that these oligosaccharides could be used as natural alternatives to crop protection chemicals for controlling these two mycotoxins.

Extracellular nucleotide metabolism controls thrombosis and inflammation and may affect degeneration and calcification of aortic valve prostheses. We evaluated the effect of different decellularization strategies on enzyme activities involved in extracellular nucleotide metabolism. Porcine valves were tested intact or decellularized either by detergent treatment or hypotonic lysis and nuclease digestion. The rates of ATP hydrolysis, AMP hydrolysis, and adenosine deamination were estimated by incubation of aorta or valve leaflet sections with substrates followed by HPLC analysis. We demonstrated relatively high activities of ecto-enzymes on porcine valve as compared to the aortic wall. Hypotonic lysis/nuclease digestion preserved >80 % of ATP and AMP hydrolytic activity but reduced adenosine deamination to

The olive woody waste (OWWis a promising feedstock for biorefineries in the Mediterranean region. In order to valorize this lignocellulosic residue, a pretreatment is necessary to fractionate its components and to improve the cellulose enzymatic hydrolyzability. The work target was to compare the efficiency of two physicochemical pretreatments, viz.: Steam Explosion (SE) and Hot Water/OrganoSolv (OS) towards acid fractionation of OWW and enzymatic digestibility of the cellulosic residue. The SE pretreatment was performed with a batch reactor of 10 L, coupled with a 125 kW boiler. The biphasic Hot Water/OrganoSolv (OS) pretreatment was carried out with a high pressure and temperature batch reactor of a 0.5 l vessel with adjustable internal stirrer and heat control. After SE and Hot Water/OrganoSolv (OS) pretreatments the materials were extracted by water to remove and quantify the soluble hemicellulose as monomers and oligomers as well as the inhibitors; the solid residue was saccharified. The digestibility of cellulose was very good in both cases, OS was slightly more effective in terms of sugars recovery. © 2018 ETA-Florence Renewable Energies.

Protein hydrolysates are largely used as plant biostimulants for boosting crop growth, and improving crop tolerance to abiotic stresses and fruit quality. Protein hydrolysate-based biostimulants are mostly produced by chemical hydrolysis starting from animal wastes. However, an innovative process of enzymatic hydrolysis of legume-derived proteins has been recently introduced by few companies. The objective of this study was to evaluate the energy use and environmental impact of the production processes of enzymatically-produced protein hydrolysate starting from lupine seeds and protein hydrolysate obtained from chemical hydrolysis of leather wastes through the application of life cycle assessment (LCA). The LCA method was applied through the software GEMIS “Global Emission Model for Integrated Systems”, elaborated at L’Oko-Institute in Germany, and the parameters taken into account were: CO2 emissions in g per kg of protein hydrolysate; the consumption of fossil energy expressed in MJ per kg of protein hydrolysate; and water consumption reported in kg per kg of protein hydrolysate. In the case of legume-derived protein hydrolysate, the evaluation of the energy use and the environmental impact started from field production of lupine grains and ended with the industrial production of protein hydrolysate. In the case of animal-derived protein hydrolysate, the LCA method was applied only in the industrial production process, because the collagen is considered a waste product of the leather industry. The type of hydrolysis is the step that most affects the energy use and environmental impact on the entire industrial production process. The results obtained in terms of CO2 emissions, fossil energy consumption and water use through the application of LCA showed that the production process of the animal-derived protein hydrolysate was characterized by a higher energy use (+26%) and environmental impact (+57% of CO2 emissions) in comparison with the enzymatic production process of lupine-derived protein hydrolysate. In conclusion, the production of legume-derived protein hydrolysate by enzymatic hydrolysis is more environmentally friendly than the production of animal-derived protein hydrolysate through chemical hydrolysis.

Ruta chalepensis L. (Rutaceae) leaf extract was investigated for its chemical profile and antioxidant and hypoglycaemic properties. The antioxidant effects were investigated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), Chi-carotene bleaching, and metal chelating activity assays. The carbohydrate-hydrolysing enzymes inhibition assay was used to test the hypoglycaemic potential. R. chalepensis showed a high content of hesperidin and rutin with values of 591.9 and 266.7 mg/g dry extract, respectively. The extract exhibited a promising protection of lipid peroxidation (IC50 value of 16.9 mu g/mL) and inhibited both alpha-amylase and alpha-glucosidase enzymes in a concentration-dependent manner. The highest activity was found against alpha-amylase (IC50 value of 69.0 mu g/mL). The obtained results support the use of R. chalepensis leaves as healthy food ingredients.

A paddle dryer system having working volume of 0.025 m3 was used as non-conventional bioreactor to carry out enzymatic hydrolysis (EH) of steam exploded (SE) wheat straw. The purpose was to increase the efficiency of saccharification in the case of slurries with high load of solid by exploiting the excellent mixing performance of the machinery. The substrate was obtained by steam explosion at 210 °C for 6 minutes, washed with water to remove hemicellulose and inhibitors. The tests showed that the cellulose conversion in glucose can reach the yield of 66% even at solid/liquid suspension ratio as high as 0.3 w/w versus typical values of 50% that were achieved using a standard bioreactor equipped with different kinds of impellers., Proceedings of the 25th European Biomass Conference and Exhibition, 12-15 June 2017, Stockholm, Sweden, pp. 1362-1364

Waste lettuce leaves - from the "fresh cut vegetable" industry - were pretreated with the deep eutectic solvent (DES) made of choline chloride - glycerol. Reaction time (3-16 h) and the operation temperature (80-150 °C) were investigated. Enzymatic glucose and xylose yields of 94.9% and 75.0%, respectively were obtained when the biomass was pretreated at 150 °C for 16 h. Sugars contained in the biomass hydrolysate were fermented in batch cultures of Clostridium acetobutylicum DSMZ 792. The energy consumption and the energy efficiency related to the DES pretreatment were calculated and compared to the most common lignocellulosic pretreatment processes reported in the literature. The DES pretreatment process was characterized by lower energy required (about 28% decrease and 72% decrease) than the NAOH pretreatment and steam explosion process respectively. The Net Energy Ratio (NER) value related to butanol production via DES biomass pretreatment was assessed.

Background In vivo assays cannot always be conducted because of ethical reasons, technical constraints or costs, but a better understanding of the digestive process, especially in infants, could be of great help in preventing food-related pathologies and in developing new formulas with health benefits. In this context, in vitro dynamic systems to simulate human digestion and, in particular, infant digestion could become increasingly valuable. Objective To simulate the digestive process through the use of a dynamic model of the infant gastroenteric apparatus to study the digestibility of starch-based infant foods. Design Using M.I.D.A (Model of an Infant Digestive Apparatus), the oral, gastric and intestinal digestibility of two starch-based products were measured: 1) rice starch mixed with distilled water and treated using two different sterilization methods (the classical method with a holding temperature of 121°C for 37 min and the HTST method with a holding temperature of 137°C for 70 sec) and 2) a rice cream with (premium product) or without (basic product) an aliquot of rice flour fermented by Lactobacillus paracasei CBA L74. After the digestion the foods were analyzed for the starch concentration, the amount of D-glucose released and the percentage of hydrolyzed starch. Results An in vitro dynamic system, which was referred to as M.I.D.A., was obtained. Using this system, the starch digestion occurred only during the oral and intestinal phase, as expected. The D-glucose released during the intestinal phase was different between the classical and HTST methods (0.795 grams for the HTST versus 0.512 for the classical product). The same analysis was performed for the basic and premium products. In this case, the premium product had a significant difference in terms of the starch hydrolysis percentage during the entire process. Conclusions The M.I.D.A. system was able to digest simple starches and a more complex food in the correct compartments. In this study, better digestibility of the premium product was revealed.

The umbilical cord is a conduit between the developing foetus and the placenta. In physiological conditions it contains two arteries and one vein immersed in a mucoid tissue called Wharton׳s jelly. Although the extreme importance of such a structure is fully recognized, the umbilical cord and its components have been scarcely studied. A deep investigation on the biomechanics of the umbilical cord could help to understand if the pregnancy outcome is influenced by umbilical cord mechanical properties, however, detailed biomechanical data are still lacking. In the present study, the mechanical properties during compression of the human Wharton׳s jelly have been evaluated using a poroelastic approach. Multi-ramp stress-relaxation tests in both confined and unconfined configurations were performed on Wharton׳s jelly samples extracted from foetal and placental sides of twenty human umbilical cords. The Young modulus and Aggregate modulus were calculated at three strain levels and the hydraulic permeability was found by fitting the confined stress-relaxation data to the analytical solution and minimizing the stress least square differences. The Wharton׳s jelly exhibits a highly non linear and viscoelastic behaviour showing a dependence on the applied strain values and a ~90% and ~85% relaxation in unconfined and confined configuration, respectively. Moreover, equilibrium Young and Aggregate moduli resulted significantly higher and the permeability significantly lower at the foetal than the placental site, showing a dependence of the three material parameters on the location (foetal or placental) and, consequently, a non-homogeneity in the Wharton׳s jelly mechanical properties.

Catalytic conversion of actual biomass to valuable chemicals is a crucial issue in green chemistry. This review discusses on the recent approach in the levulinic acid (LA) formation from three prominent generations of biomasses. Our paper highlights the impact of the nature of different types of biomass and their complex structure and impurities, different groups of catalyst, solvents, and reaction system, and condition and all related pros and cons for this process.

A mononucleating (HL(1)) and a dinucleating (HL(2)) "end-off" compartmental ligand have been designed and synthesized by controlled Mannich reaction using p-cresol and bis(2-methoxyethyl)amine, and their formation has been rationalized. Six complexes have been prepared on treating HL(1) and HL(2) with Zn(II)X2 (X = Cl(-), Br(-), I(-)) with the aim to investigate their hydrolytic activity on phosphoester bond cleavage. Interestingly, the mononucleating ligand was observed to yield dinuclear complexes, [Zn2(L(1))2X2] (1-3), while the potential dinucleating ligand generated mononuclear complexes, [Zn(HL(2))X2] (4-6). Four (1-4), out of six complexes studied, were characterized by single-crystal X-ray diffraction (XRD): the Zn ion exhibits trigonal bipyramidal and tetrahedral coordination spheres in the di- and mononuclear complex, respectively. The hydrolytic kinetics, followed spectrophotometrically with 4-nitrophenylphosphate (4-NPP) in buffered dimethylformamide (DMF) (97.5% DMF, v/v) because of solubility reasons, under excess substrate conditions (substrate:complex = 20:1), indicated that the complexes enormously accelerate the rate of phosphomonoester hydrolysis with first order rate constants (kcat) in the range 2-10 s(-1) at 25 °C. In each case kinetic data analyses have been run by Michaelis-Menten treatment. The efficacy in the order of conversion of substrate to product (p-nitrophenolate ion) follows the trend 123456, and the ratio of kcat of an analogous dinuclear to mononuclear complex is ≃2. An electrospray ionization-mass spectrometry (ESI-MS) study has revealed the dissociation of the centrosymmetric dinuclear complex to two mononuclear species instead of a syn-cooperative catalysis. Density functional theory (DFT) calculations have been performed to rationalize our proposed mechanistic pathway for phosphatase activity. The comparative analysis concludes the following facts under experimental conditions: (1) the halide bound to the active site affects the overall rate in the order: Cl(-)Br(-)I(-) regardless of nuclearity; (2) dinuclear complexes prevail over the mononuclear ones.

The development of new antibiotics with low environmental persistence is of utmost importance in contrasting phenomena of antibiotic resistance. In this study, the persistence of two newly synthesized monocyclic beta-lactam antibiotics: (2R)-1-(methylthio)-4-oxoazetidin-2-yl acetate, P1, and (2R,3R)-3-((1R)-1-(tert-butyldimethylsilanyloxy)ethyl)-1-(methylthio)-4-oxoazetidin-2-yl acetate, P2, has been investigated in water in the pH range 3-9 and in two (calcareous and forest) soils, then compared to amoxicillin, a beta-lactam antibiotic used in human and veterinary medicine. P1 and P2 persistence in water was lower than that of amoxicillin with only a few exceptions. P1 hydrolysis was catalyzed at an acidic pH whereas P2 hydrolysis takes place at both acidic and alkaline pH values. P1 persistence in soils depended mainly on their water potential (t(1/2): 35.0-70.7 d at wilting point

Although the term nanozymes was coined by us in 2004 to highlight the enzyme-like properties of gold nanoparticles passivated with a monolayer of Zn(II)-complexes in the cleavage of phosphate diesters, systems resembling those metallo-nanoparticles, like micelles and vesicles, have been the subject of investigation since the mid-eighties of the last century. This paper reviews what has been done in the field and compares the different nanosystems highlighting the source of catalysis and frequent misconceptions found in the literature.

Sphingolipids have hydrophilic and hydrophobic properties, different saturation and combination of the oligosaccharide chains and mass homology of species located in a narrow m/z region hampering their recognition. To target sphingolipids for diagnostic purposes, standardized methods for lipid extraction, quali- and quantitative assessments are required. In this study, HPTLC-MALDI MS was adopted to establish sphingolipid and glycosphingolipid profiles in muscle, brain and serum to create a database of molecules to be searched in the preclinical and clinical investigations. Specific protocols for lipid extraction were set up based on the characteristics of the tissue or/and fluids; this approach maximizes the HPTLC-MALDI MS analytical throughput both for lipids extracted in organic and aqueous phase. This study indicates that alkaline hydrolysis is necessary for the detection of low abundant species such as Gb3Cer and ceramides in serum and Gb4Cer, CerP and HexCer in muscle tissue. The high hydrophobicity of ceramides has been overcome by the development of HPTLC plate in chloroform:methanol/50:3.5, which increases the number and the intensity of low abundant Cer species. MS/MS analysis has been conducted directly on HPTLC plate allowing the molecular recognition; furthermore a dataset of spectra was acquired to create a database for future profiling of these molecules.

A chemical investigation of the interaction mechanisms of nicotine with the metal(II) ions Pb $$ ^{2+} $$ , Fe $$ ^{2+} $$ , and Cu $$ ^{2+} $$ is reported. The complex formation between nicotine and metal(II) has been investigated at 25.00 $$ \pm $$ 0.02 $$^{\circ }$$ C, in constant ionic medium (as sodium perchlorate, or sodium chloride), by UV/Vis spectrophotometric and potentiometric methods. The experimental method consists of coulometric or volumetric titrations. The protolysis constants of nicotine have been determined under the same experimental conditions. The pH investigated spans between 3 and 10. By using the specific ion interaction theory the conditional constants of nicotine have been extrapolated at zero ionic strength. The results of the graphical and numerical methods adopted indicate, for all the systems investigated, the formation of a predominating Me(II)/nicotine mononuclear complexes.

Halomonas pantelleriensis DSM9661Τ is a Gram-negative haloalkaliphilic bacterium isolated from the sand of the volcanic Venus mirror lake, closed to seashore in the Pantelleria island in the south of Italy. It is able to optimally grow in media containing 3-15% (w/v) total salt and at pH between 9-10. To survive in these harsh conditions the bacterium has developed several strategies that probably concern the bacteria outer membrane, a barrier regulating the exchange with the environment. In such a context the lipopolysaccharides (LPSs), which are among the major constituent of the Gram-negative outer membrane, are thought to contribute to the restrictive membrane permeability properties. The structure of the lipid A family derived from the lipopolysaccharide of Halomonas pantelleriensis DSM 9661T is reported herein. The lipid A was obtained from the purified LPS by mild acid hydrolysis. The lipid A, which contains different numbers of fatty acids residues, and its partially deacylated derivatives were completely characterized by means of ESI FT-ICR mass spectrometry and chemical analysis. Preliminary immunological assays were performed, and a comparison with the lipid A structure of the phylogenetic proximal Halomonas magadiensis is also reported.

Organotin(IV) cations behave as Lewis acids of different strength depending on the charge, according to the following acidity scale: RSn3+ > R2Sn2+ > R3Sn+. For this reason they can react with Lewis bases containing –O, –N, –S donor groups to form complex species of different stability. Complex formation of organotin(IV) moieties with a great number of inorganic and organic ligands in aqueous solution is reviewed here in the light of their environmental and biological impact. To this end, complex species formation was considered in different ionic media and at different ionic strengths, with reference to the composition of natural waters and biological fluids. In particular, the interaction of alkyltin(IV) compounds with the following ligands was taken into account: hydroxo, chloride, sulfate, fluoride, carbonate and phosphate; carboxylates, amines, amino-carboxylates, nucleotides, saccharides, S-containing ligands and antibiotics. Moreover, the interaction of organotin(IV) cations with synthetic (polyacrylate) and natural occurring (fulvic and alginic acids) polyelectrolytes was also considered. The strength of interaction is reported in terms of stability constants of complex species formed and of other thermodynamic parameters, such as formation enthalpy. The stability trend of the complexes is alkyltin(IV)-S > alkyltin(IV)-N > alkyltin(IV)-O-donor ligands. On the basis of data in the literature, empirical relationships are provided to predict the stability of alkyltin(IV) species with some classes of ligands. The complexation models proposed by the different authors for the species formation of mono-, di- and tri-alkyltin(IV) in the presence of various ligands were considered in the light of defining the speciation picture of this class of compounds in aquatic systems.

IMiDs compounds are a class of analogues of thalidomide, with greater immunomodulatory activity and a superior safety profile compared to the parent compound. They show substantial increase in potency and an interesting tolerability profile, primarily due to a decreased incidence of the most severe side effect of thalidomide, i.e. Chemotherapy-Induced Peripheral Neurotoxicity (CIPN). These novel aspects of the IMiDs compounds will be discussed.

Multivalent systems are well known for their enhanced ability to bind multivalent counterparts. This contribution addresses the question whether they can also behave as cooperative catalysts. Analyzing examples from our own laboratory we show that self-assembled systems obtained by covering gold nanoclusters with thiol-terminated amino acids and peptides behave indeed as cooperative catalysts. By comparing their activity profiles with those of discrete, multivalent systems we show what are minimal conditions to elicit cooperativity in multivalent systems. Reactions taken into considerations for our analysis are the hydrolyses of carboxylate- and phosphate esters. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd.

This paper reports the study of the photodegradation reactions that tricyclazole can naturally undergo, under the action of sunlight, in aqueous solutions of standard tricyclazole and of the commercial BEAM(TM) formulation. The analyses are carried out by ultra-high performance liquid chromatography technique coupled with high-resolution tandem mass spectrometry. Analysis of both tricyclazole and BEAM(TM) water solutions undergone to hydrolysis does not evidence new chromatographic peaks with respect to the not treated solutions. On the contrary, analysis of the same samples subjected to sunlight irradiation shows a decreased intensity of tricyclazole signal and the presence of new chromatographic peaks. Two photodegradation products of tricyclazole have been identified, one of which has been also quantified, being the commercial standard available. The pattern is similar for the solutions of the standard fungicide and of the BEAM(TM) formulation. The results obtained from eco-toxicological tests show that toxicity of tricyclazole standard solutions is greater than that of the irradiated ones, whereas toxicity levels of all the BEAM(TM) solutions investigated (non-irradiated, irradiated, and hydrolyzed) are comparable and lower than those shown by tricyclazole standard solutions. Experiments performed in paddy water solution show that there is no difference in the degradation products formed.

An enzymatic mixture of cellulases and xylanases was produced byPleurotus ostreatususing microcrystalline cellulose as inducer, partially characterized and tested in the statistical analysis ofArundo donaxbioconversion. The Plackett-Burman screening design was applied to identify the most significant parameters for the enzymatic hydrolysis of pretreatedA. donax. As the most significant influence during the enzymatic hydrolysis ofA. donaxwas exercised by the temperature (°C), pH, and time, the combined effect of these factors in the bioconversion byP. ostreatuscellulase and xylanase was analyzed by a 33factorial experimental design. It is worth noting that the best result of 480.10 mg of sugars/gds, obtained at 45°C, pH 3.5, and 96 hours of incubation, was significant also when compared with the results previously reached by process optimization with commercial enzymes.

Among agro-wastes, olive mill wastewater (OMW) truly qualifies as a high impact organic residue due to its biochemical-rich composition and high annual production. In the present investigation, dephenolized OMW (OMWdeph) was employed as the feedstock for a biotechnological two-stage anaerobic process dedicated to the production of biohydrogen and volatile fatty acids (VFAs), respectively. To this end, two identically configured packed-bed biofilm reactors were operated sequentially. In the first, the hydraulic retention time was set to 1 day, whereas in the second it was equal to 5 days. The rationale was to decouple the hydrolysis of the organic macronutrients held by the OMWdeph, so as to quantitatively generate a biogas enriched in H2 (first stage aim), for the acidogenesis of the residual components left after hydrolysis, to then produce a highly concentrated mixture of VFAs (second stage aim). Results showed that the generation of H2 and VFAs was effectively split, with carbohydrates and lipids, respectively, being the main substrates of the two processes. About 250 ml H2 L(-1) day(-1) was produced, corresponding to a yield of 0.36 mol mol(-1) of consumed carbohydrates (expressed as glucose equivalents). The overall concentration of VFAs in the acidogenic process was 13.80 g COD L(-1), so that 2.76 g COD L(-1) day(-1) was obtained. Second generation biorefineries use a selected fraction of an organic waste to conduct a microbiologically-driven pathway towards the generation of one target molecule. With the proposed approach, a greater value of the waste was attained, since the multi-purpose two-stage process did not entail competition for substrates between the first and the second steps.

The formation of the hydrolytic complexes of U(IV) has been investigated by measuring the potential of inert sponges and of a glass electrode, at 25.00 °C, in 3 M NaClO4, in solutions containing both U(VI) and U(IV) at acidities between 10-0.5 and 10-1.8 M.The experimental data can be explained by assuming the formation of two mononuclear complexes, UOH3+ and U(OH)4. Their formation constants in the ionic medium 3 M NaClO4 are: log*β1=-1.62±0.01 and log*β4=-7.70±0.03. The formal standard potential E°6,4 for the couple UO22+/U4+ in the same conditions, is (335.7±0.5) mV.

A mixture of novel glycopeptides from glycosylation between cold water fish skin gelatin hydrolysates and glucosamine (GlcN) via transglutaminase (TGase), as well as glycation between fish gelatin hydrolysate and GlcN were identified by their pattern of molecular distribution using MALDI-TOF-MS. Glycated/ glycosylated hydrolysates showed superior bioactivity to their original hydrolysates. Alcalase-derived fish skin gelatin hydrolysate glycosylated with GlcN in the presence of TGase at 25 °C (FAT25) possessed antioxidant activity when tested in a linoleic acid oxidation system, when measured according to its 2,2- diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and when tested at the cellular level with human hepatocarcinoma (HepG2) cells as target cells. In addition, Alcalase-derived glycosylated hydrolysates showed specificity toward the inhibition of Escherichia coli (E. coli). The Flavourzyme-derived glycopeptides prepared at 37 °C (FFC37 and FFT37) showed better DPPH scavenging activity than their native hydrolysates. The glycated Flavourzyme-derived hydrolysates were found to act as potential antimicrobial agents when incubated with E. coli and Bacillus subtilis. © 2013 Elsevier Ltd. All rights reserved.

Protein machines often exhibit long range interplay between different sites in order to achieve their biological tasks. We investigate and characterize the non--linear energy localization and the basic mechanisms of energy transfer in protein devices. By studying two different model protein machines, with different biological functions, we show that genuinely non--linear phenomena are responsible for energy transport between the different machine sites involved in the biological functions. The energy transfer turns out to be extremely efficient from an energetic point of view: by changing the energy initially provided to the model device, we identify a well defined range of energies where the time for the energy transport to occur is minimal and the amount of transferred energy is maximum. Furthermore, by introducing an implicit solvent, we show that the energy is localized on the internal residues of the protein structure, thus minimizing the dissipation.

In an Anaerobic Digestion (AD) process treating particulate substrates, the size of solids is expected to negatively affect the rate of hydrolysis step and consequently influence the performance of the whole process. To avoid any disadvantage due to size of solids, expensive pre-treatments aimed at disintegrating and solubilizing substrates are commonly conducted prior to AD. This practice is doubtlessly successful, but not always necessary, since some organic substrates, although particulate, once immersed in water, tend to solubilize immediately. This aspect, if properly considered, could result in saving money and time in the AD process, as well as refining the development and calibration of AD mathematical models. The present study is actually aimed at demonstrating, through experiments and mathematical simulations, different results deriving from the AD process performed, under the same operating conditions, on two different substrates, i.e. homemade pasta and carrot batons, having the same particle size, but different chemical composition and texture. Experimental outcomes highlighted the effect of particles size on bio-methane production only from the bio-methanation potential tests (BMP) conducted on carrot batons. Similar results were obtained by mathematical model calibration, i.e. , different kinetic constants for differently-sized carrot batons and same kinetic constant for differently-sized homemade pasta solids.

This paper compares the catalytic behavior of several heterogeneous acid catalysts in the direct hydrolysis of an untreated softwood dust. Among the various catalysts investigated, some were characterized by a relatively high yield to monosaccharides, such as a Zirconium phosphate and the reference Amberlyst 15. Conversely, some catalyst types, i.e. Sn/W mixed oxide and Zirconia-grafted trifluoromethanesulfonic acid, were selective into glucose, since sugars derived from hemicellulose dissolution and hydrolysis were rapidly degraded. A detailed analysis of the reactivity of Zr/P/O was conducted, in the hydrolysis of both untreated and ball-milled microcrystalline cellulose; at 150 °C and 3 h reaction time, the catalyst gave high selectivity to glucose, with negligible formation of 5-hydroxymethylfurfural, and moderate cellulose conversion. After cellulose ball-milling, a notable increase in conversion was achieved, still with a high selectivity to glucose and very low formation of degradation compounds. The catalyst showed high affinity for β-1,4-glucans, as demonstrated by the activity in cellobiose hydrolysis into glucose.

Knowledge of the kinetics and pathways of hydrolytic degradation is crucial to the prediction of the fate and transport mechanism of chemicals. This work first describes the kinetics of the chemical hydrolysis of imazosulfuron, a new sulfonylurea herbicide, and evaluates the results to propose a degradation pathway. The hydrolysis of imazosulfuron has been studied in aqueous buffers both within the pH range 1.9-12.3 at ambient temperature (thermostated at 25 +/- 2 degrees C) and at pH 3.6 within the temperature range of 15-55 degrees C. The hydrolysis rate of imazosulfuron was characterized by a first-order kinetics, pH- and temperature-dependent, and accelerated by acidic conditions and higher temperatures. The calculated half-lives at pH 4.5 and 5.9 were 36.5 and 578 days, respectively. At pH 6.6, 7.4, 9.2, and 12.3 no significant change in imazosulfuron concentration was observed after 150 days. Half-lives were much lower at pH4 (= imazosulfuron pK(a)), at which they ranged from 3.3 to 6.3 days. Moreover, a change in temperature from 15 to 25 degrees C in acidic conditions (pH 3.6) decreased the half-life of imazosulfuron by a factor of approximately 4.0; in any case, a 3-5-fold increase in the rate of hydrolysis was found for each 10 degrees C increase in temperature. In acidic conditions the only hydrolysis products were the two molecules resulting from the cleavage of the sulfonylurea bridge.

In our research, a phytochemical screening was performed by the method of Cain - Bohmann modified yielding presence of good amount of saponins, which were identified as triterpenoid saponins using qualitative tests that were positive and the test of the foam reaction with the reagent Salwosky, Bouchard Liberman reagent and reaction with sulfuric acid. Three quantitative methods for extracting saponins from a hydroalcoholic extract of the plant and subsequent hydrolysis were developed. The difference of the first two methods was to use a method with the sample defatted with chloroform and the other without scouring . For the third method according to the procedure applied M.E.Wall et al. (1958). Extraction rates for the three methods saponins were 3.90%, 2.40 % and 2.02% respectively. Similarly the corresponding aglycones after acid were obtained by hydrolyzing the crude obtained via., obteniéndose presencia de buena cantidad de saponinas, las cuales fueron identificadas como saponinas triterpenoides utilizando pruebas cualitativas que dieron positivas como la prueba de la espuma, reacción con el reactivo de Salwosky, reactivo de Liberman-Bouchard y reacción con el ácido sulfúrico. Se desarrollaron tres metodologías cuantitativas para la extracción de las saponinas a partir de un extracto hidroalcohólico de la planta y su posterior hidrólisis. La diferencia de los dos primeros métodos consistió en emplear un método con la muestra desengrasada con cloroformo y el otro sin desengrasar. Para el tercer método se aplicó el procedimiento según M.E.Wall et al. (1958). Los porcentajes de extracción de saponinas para las tres metodologías fueron de 3,90%, 2,40% y 2,02% respectivamente. Igualmente se obtuvieron las agliconas correspondientes luego de hidrolizar por vía ácida el crudo obtenido.

We here report the first molecular characterization of an alpha-xylosidase (XylS) from an Archaeon. Sulfolobus solfataricus is able to grow at temperatures higher than 80 degrees C on several carbohydrates at acidic pH. The isolated xylS gene encodes a monomeric enzyme homologous to alpha-glucosidases, alpha-xylosidases, glucoamylases and sucrase-isomaltases of the glycosyl hydrolase family 31. xylS belongs to a cluster of four genes in the S. solfataricus genome, including a beta-glycosidase, an hypothetical membrane protein homologous to the major facilitator superfamily of transporters, and an open reading frame of unknown function. The alpha-xylosidase was overexpressed in Escherichia coli showing optimal activity at 90 degrees C and a half-life at this temperature of 38 h. The purified enzyme follows a retaining mechanism of substrate hydrolysis, showing high hydrolytic activity on the disaccharide isoprimeverose and catalyzing the release of xylose from xyloglucan oligosaccharides. Synergy is observed in the concerted in vitro hydrolysis of xyloglucan oligosaccharides by the alpha-xylosidase and the beta-glycosidase from S. solfataricus. The analysis of the total S. solfataricus RNA revealed that all the genes of the cluster are actively transcribed and that xylS and orf3 genes are cotranscribed.

A special type of bioreactor was designed and tested in order to improve the bioethanol production from lignocellulosic materials via enzymatic hydrolysis and fermentation. The reactor consists of two chambers kept at different temperatures and separated by a porous medium, through which the solutes can diffuse. The reactor was tested using as substrate wheat straw previously steam exploded and detoxified. The yields of cellulose hydrolysis and glucose fermentation obtained using this reactor were compared to those obtained by simultaneous enzymatic hydrolysis and fermentation (SSF) carried out in only one vessel. The results showed that a significant increase in the ethanol yield (20%) can be achieved by using this bioreactor. An additional advantage of the reactor is the confinement of the solid lignin in one chamber, allowing a simplified separation process between broth and unreacted residue. © 2012 Elsevier Ltd.

The aim of this work was to investigate the behavior of vegetable oils (corn (CO), vitaminized corn (COVE), sunflower (SO) and peanut (PO) oils), under standardized domestic frying conditions using a deep-fryer and a frying-pan. In both frying experiments, prefried potato sticks were deep-fried at 160°C (potato:oil ratio, 1:3 (w/w)). Each frying cycle consisted of a first heating step of oil, followed by 2 repeated frying sessions with an re-equilibration time interval between them. The oxidative and hydrolytic stability of the vegetable oils were evaluated. After the second frying session, a slight reduction in the polyunsaturated fatty acid content (2.5-3.3%) was observed in both cooking modes. In general, the oxidative stability index (OSI) of all vegetable oils decreased during frying in both experimental conditions; in particular, CO and COVE displayed a similar behavior to PO, whereas SO showed the lowest OSI time (2.6 h after the second frying). Peroxide value (PV) of all oils rose faster and reached higher levels in the frying-pan with respect to the deep-fryer; after the second frying session, most oils had a PV lower than 17 meq O2/kg oil, except for SO (30 meq O2/kg oil). Regarding the hydrolytic stability, free acidity (< 0.2%) and total diacylglycerol content (1.3-2.7% mg/100 mg of fat) remained almost constant in all oils under both tested conditions. In addition, total polar compounds (TPC) of all oils did not exceed 22% in both cooking methods, thus being below the legal limit for TPC (< 25%). Finally, a sensory evaluation of fried potatoes was carried out by randomly chosen volunteers (n=10), who gave the lowest general assessment to products fried with PO regardless of the cooking mode. In general, CO, COVE and PO showed a similar oxidative and hydrolytic behavior under the household frying conditions here tested, but SO easily and faster degraded, thus being less suitable for domestic frying.

Phenylureas such as diuron are major herbicides used worldwide to control undesirable weeds. The environmental fate of phenylureas is of great interest because massive amounts of those herbicides are used. It is known that abiotic degradation of phenylureas in soil-water systems is catalyzed by humic acids. However, due to the chemical heterogeneity and large molecular sizes of humic acids, the specific effects of functional groups during catalysis have not been elucidated. Therefore, we studied here for the first time the kinetics of diuron degradation in the presence of low molecular weight humic acid-like compounds such as benzoic acid derivatives. Experiments were carried out at various pH and temperature, and monitored by high-performance liquid chromatography. Results show that all benzoic acid derivatives efficiently catalyzed diuron hydrolysis. The catalytic efficiency decreased in the following order: 0.88 M-1 day-1 for 3,4-dihydroxybenzoic acid, 0.72 M-1 day-1 for 4-hydroxybenzoic acid, 0.23 M-1 day-1 for phthalic acid, 0.11 M-1 day-1 for 2-hydroxybenzoic acid, and 0.09 M-1 day-1 for 2,4-dihydroxybenzoic acid. These differences in the catalytic efficiency are explained by steric hindrance affecting the accessibility of reactive sites and hence influencing the rate of the overall process. Steric factors are therefore expected to control the catalytic activity of humic acids because of the chemical similarities between humic acids and low molecular weight humic acid-like compound. Our results should help predict more accurately the fate and abiotic degradation mechanism of phenylureas in the environment. © 2013 Springer-Verlag Berlin Heidelberg.