2016 Nobel Prize in Physiology or Medicine

The Nobel Assembly at Karolinska Institutet has today decided to award the 2016 Nobel Prize in Physiology or Medicine to

Yoshinori Ohsumi

"for his discoveries of mechanisms for autophagy"

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This year's Nobel Laureate discovered and elucidated mechanisms underlying autophagy, a fundamental process for degrading and recycling cellular components.  

The word autophagy originates from the Greek words auto-, meaning "self", and phagein, meaning "to eat". Thus,autophagy denotes "self eating". This concept emerged during the 1960's, when researchers first observed that the cell could destroy its own contents by enclosing it in membranes, forming sack-like vesicles that were transported to a recycling compartment, called the lysosome, for degradation. Difficulties in studying the phenomenon meant that little was known until, in a series of brilliant experiments in the early 1990's, Yoshinori Ohsumi used baker's yeast to identify genes essential for autophagy. He then went on to elucidate the underlying mechanisms for autophagy in yeast and showed that similar sophisticated machinery is used in our cells.

Ohsumi's discoveries led to a new paradigm in our understanding of how the cell recycles its content. His discoveries opened the path to understanding the fundamental importance of autophagy in many physiological processes, such as in the adaptation to starvation or response to infection. Mutations in autophagy genes can cause disease, and the autophagic process is involved in several conditions including cancer and neurological disease.

Degradation – a central function in all living cells

In the mid 1950's scientists observed a new specialized cellular compartment, called an organelle, containing enzymes that digest proteins, carbohydrates and lipids. This specialized compartment is referred to as a "lysosome" and functions as a workstation for degradation of cellular constituents. The Belgian scientist Christian de Duve was awarded the Nobel Prize in Physiology or Medicine in 1974 for the discovery of the lysosome. New observations during the 1960's showed that large amounts of cellular content, and even whole organelles, could sometimes be found inside lysosomes. The cell therefore appeared to have a strategy for delivering large cargo to the lysosome. Further biochemical and microscopic analysis revealed a new type of vesicle transporting cellular cargo to the lysosome for degradation (Figure 1). Christian de Duve, the scientist behind the discovery of the lysosome, coined the term autophagy, "self-eating", to describe this process. The new vesicles were named autophagosomes.

Figure 1: Our cells have different specialized compartments. Lysosomes constitute one such compartment and contain enzymes for digestion of cellular contents. A new type of vesicle called autophagosome was observed within the cell. As the autophagosome forms, it engulfs cellular contents, such as damaged proteins and organelles. Finally, it fuses with the lysosome, where the contents are degraded into smaller constituents. This process provides the cell with nutrients and building blocks for renewal.

During the 1970's and 1980's researchers focused on elucidating another system used to degrade proteins, namely the "proteasome". Within this research field Aaron Ciechanover, Avram Hershko and Irwin Rose were awarded the 2004 Nobel Prize in Chemistry for "the discovery of ubiquitin-mediated protein degradation". The proteasome efficiently degrades proteins one-by-one, but this mechanism did not explain how the cell got rid of larger protein complexes and worn-out organelles. Could the process of autophagy be the answer and, if so, what were the mechanisms?

A groundbreaking experiment

Yoshinori Ohsumi had been active in various research areas, but upon starting his own lab in 1988, he focused his efforts on protein degradation in the vacuole, an organelle that corresponds to the lysosome in human cells. Yeast cells are relatively easy to study and consequently they are often used as a model for human cells. They are particularly useful for the identification of genes that are important in complex cellular pathways. But Ohsumi faced a major challenge; yeast cells are small and their inner structures are not easily distinguished under the microscope and thus he was uncertain whether autophagy even existed in this organism. Ohsumi reasoned that if he could disrupt the degradation process in the vacuole while the process of autophagy was active, then autophagosomes should accumulate within the vacuole and become visible under the microscope. He therefore cultured mutated yeast lacking vacuolar degradation enzymes and simultaneously stimulated autophagy by starving the cells. The results were striking! Within hours, the vacuoles were filled with small vesicles that had not been degraded (Figure 2). The vesicles were autophagosomes and Ohsumi's experiment proved that authophagy exists in yeast cells. But even more importantly, he now had a method to identify and characterize key genes involved this process. This was a major break-through and Ohsumi published the results in 1992.

Figure 2: In yeast (left panel) a large compartment called the vacuole corresponds to the lysosome in mammalian cells. Ohsumi generated yeast lacking vacuolar degradation enzymes. When these yeast cells were starved, autophagosomes rapidly accumulated in the vacuole (middle panel). His experiment demonstrated that autophagy exists in yeast. As a next step, Ohsumi studied thousands of yeast mutants (right panel) and identified 15 genes that are essential for autophagy.

Autophagy genes are discovered

Ohsumi now took advantage of his engineered yeast strains in which autophagosomes accumulated during starvation. This accumulation should not occur if genes important for autophagy were inactivated. Ohsumi exposed the yeast cells to a chemical that randomly introduced mutations in many genes, and then he induced autophagy. His strategy worked! Within a year of his discovery of autophagy in yeast, Ohsumi had identified the first genes essential for autophagy. In his subsequent series of elegant studies, the proteins encoded by these genes were functionally characterized. The results showed that autophagy is controlled by a cascade of proteins and protein complexes, each regulating a distinct stage of autophagosome initiation and formation (Figure 3).

Figure 3: Ohsumi studied the function of the proteins encoded by key autophagy genes. He delineated how stress signals initiate autophagy and the mechanism by which proteins and protein complexes promote distinct stages of autophagosome formation.

Autophagy – an essential mechanism in our cells

After the identification of the machinery for autophagy in yeast, a key question remained. Was there a corresponding mechanism to control this process in other organisms? Soon it became clear that virtually identical mechanisms operate in our own cells. The research tools required to investigate the importance of autophagy in humans were now available.

Thanks to Ohsumi and others following in his footsteps, we now know that autophagy controls important physiological functions where cellular components need to be degraded and recycled. Autophagy can rapidly provide fuel for energy and building blocks for renewal of cellular components, and is therefore essential for the cellular response to starvation and other types of stress. After infection, autophagy can eliminate invading intracellular bacteria and viruses. Autophagy contributes to embryo development and cell differentiation. Cells also use autophagy to eliminate damaged proteins and organelles, a quality control mechanism that is critical for counteracting the negative consequences of aging.

Disrupted autophagy has been linked to Parkinson's disease, type 2 diabetes and other disorders that appear in the elderly. Mutations in autophagy genes can cause genetic disease. Disturbances in the autophagic machinery have also been linked to cancer. Intense research is now ongoing to develop drugs that can target autophagy in various diseases.

Autophagy has been known for over 50 years but its fundamental importance in physiology and medicine was only recognized after Yoshinori Ohsumi's paradigm-shifting research in the 1990's. For his discoveries, he is awarded this year's Nobel Prize in physiology or medicine.

Key publications

• Takeshige, K., Baba, M., Tsuboi, S., Noda, T. and Ohsumi, Y. (1992). Autophagy in yeast demonstrated with proteinase-deficient mutants and conditions for its induction. Journal of Cell Biology 119, 301-311
• Tsukada, M. and Ohsumi, Y. (1993). Isolation and characterization of autophagy-defective mutants of Saccharomyces cervisiae. FEBS Letters 333, 169-174
• Mizushima, N., Noda, T., Yoshimori, T., Tanaka, Y., Ishii, T., George, M.D., Klionsky, D.J., Ohsumi, M. and Ohsumi, Y. (1998). A protein conjugation system essential for autophagy. Nature 395, 395-398
• Ichimura, Y., Kirisako T., Takao, T., Satomi, Y., Shimonishi, Y., Ishihara, N., Mizushima, N., Tanida, I., Kominami, E., Ohsumi, M., Noda, T. and Ohsumi, Y. (2000). A ubiquitin-like system mediates protein lipidation. Nature, 408, 488-492

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Yoshinori Ohsumi was born 1945 in Fukuoka, Japan. He received a Ph.D. from University of Tokyo in 1974. After spending three years at Rockefeller University, New York, USA, he returned to the University of Tokyo where he established his research group in 1988. He is since 2009 a professor at the Tokyo Institute of Technology.

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Fuente: The Official Web Site of the Nobel Price

Poorly-crystalline components in aggregates from soils under different land use and parent material

Catena 144 (2016) 141–150

http://dx.doi.org/10.1016/j.catena.2016.05.012

Fe and Al compounds of low degree of crystallinity are important components for the development and conser- vation of soil structure in many soils. In this work, the influence of parent material and land use on the abundance of poorly-crystalline forms of Fe and Al was studied in six macroaggregate fractions from 28 soils. The soils select- ed are developed on two geological materials with very different composition: granites or amphibolites, and under two land uses: shrubland or agricultural. Poorly crystalline Fe and Al were extracted with oxalic acid–am- monium oxalate (inorganic and organic forms), and with pyrophosphate (organic forms). Soils developed on am- phibolite were richer in organic matter and poorly-crystalline Fe and Al compounds than soils developed on granite. Agricultural soils were impoverished in organic carbon and organic-complexed Al with respect to shrub- land soils, and enriched in inorganic poorly crystalline forms of Fe. The differences related to land use were more evident in the amphibolite soils. Aggregate stability, assessed by water-dispersible clay quantification, decreased in agricultural soils with respect to shrubland soils, in particular for those developed on amphibolite. This reduc- tion of aggregate stability in agricultural soils is likely due to a combination of several processes: loss of organic matter, higher pH, and an overall loss of poorly-crystalline Fe and Al compounds, in particular Al-organic matter complexes.

Applied Microbiology and Biotechnology, 2016, 100 (18), 7899–790

DOI: 10.1007/s00253-016-7558-9

Nisin production by Lactococcus lactis CECT 539 was followed in batch cultures in whey supplemented with different concentrations of glucose and in two realkalized fed-batch fermentations in unsupplemented whey, which were fed, respectively, with concentrated solutions of lactose and glucose. In the batch fermentations, supplementation of whey with glucose inhibited both the growth and bacteriocin production. However, fed-batch cultures were characterized with high productions of biomass (1.34 and 1.51 g l−1) and nisin (50.6 and 60.3 BU ml−1) in comparison to the batch fermentations in unsupplemented whey (0.48 g l−1 and 22.5 BU ml−1) and MRS broth (1.59 g l−1 and 50.0 BU ml−1). In the two realkalized fed-batch fermentations, the increase in bacteriocin production parallels both the biomass production and pH drop generated in each realkalization and feeding cycle, suggesting that nisin was synthesized as a pH-dependent primary metabolite. A shift from homolactic to heterolactic fermentation was observed at the 108 h of incubation, and other metabolites (acetic acid and butane-2,3-diol) in addition to lactic acid accumulated in the medium. On the other hand, the feeding with glucose improved the efficiencies in glucose, nitrogen, and phosphorus consumption as compared to the batch cultures. The realkalized fed-batch fermentations showed to be an effective strategy to enhance nisin production in whey by using an appropriate feeding strategy to avoid the substrate inhibition.

Pediocin SA-1: A selective bacteriocin for controlling Listeria monocytogenes in maize silages

Journal of Dairy Science, 99 (2016) 8070–8080

http://dx.doi.org/10.3168/jds.2016-11121

In this study, we assessed the potential as silage additive of a bacteriocin produced by Pediococcus acidilactici Northern Regional Research Laboratory (NRRL) B-5627 (pediocin SA-1). Maize was inoculated either with a bacterial starter alone (I) or in combination with the bacteriocin (IP), and untreated silage served as control. We monitored the products of fermentation (ethanol, and lactic and acetic acids), the microbial population, and the presence of the indicator strain Listeria monocytogenes Colección Española de Cultivos Tipo (CECT) 4032 (1 × 105 cfu/g) after 1, 2, 5, 8, 16, and 30 d of ensiling. Our results indicated antilisterial activity of the bacteriocin, anticipating the disappearance of L. monocytogenes in IP compared with I and control silages. The PCR-denaturing gradient gel electrophoresis analysis revealed the addition of the bacteriocin did not affect the bacterial communities of the spontaneous fermentation, and the inoculant-containing bacteria (Lactobacillus plantarum, Lactobacillus buchneri, and Enterococcus faecium) were found in addition to the bacterial communities of untreated maize silages in I and IP silages. Both treatments increased the concentration of antimicrobial compounds (acetic acid, ethanol, and 1,2-propanodiol) and led to lower residual sugar contents compared with the control, which would provide enhanced aerobic stability. The fact that the identified species L. plantarum, L. buchneri, and E. faecium produce some of these inhibitory compounds, together with their persistence throughout the 30 d of fermentation, suggest these bacteria could actively participate in the ensiling process. According to these results, pediocin SA-1 could be used as an additive to control the presence of L. monocytogenes in maize silages selectively, while improving their fermentative quality and eventually their aerobic stability.

Video Presentación del CIA

Simultaneous production of amylases and proteases by Bacillus subtilis in brewery wastes

Brazilian Journal of Microbiology, 47, 2016, 665–674

http://dx.doi.org/10.1016/j.bjm.2016.04.019

The simultaneous production of amylase (AA) and protease (PA) activity by Bacillus subtilis UO-01 in brewery wastes was studied by combining the response surface methodology with the kinetic study of the process. The optimum conditions (T = 36.0 °C and pH = 6.8) for high biomass production (0.92 g/L) were similar to the conditions (T = 36.8 °C and pH = 6.6) for high AA synthesis (9.26 EU/mL). However, the maximum PA level (9.77 EU/mL) was obtained at pH 7.1 and 37.8 °C. Under these conditions, a considerably high reduction (between 69.9 and 77.8%) of the initial chemical oxygen demand of the waste was achieved. In verification experiments under the optimized conditions for production of each enzyme, the AA and PA obtained after 15 h of incubation were, respectively, 9.35 and 9.87 EU/mL. By using the Luedeking and Piret model, both enzymes were classified as growth-associated metabolites. Protease production delay seemed to be related to the consumption of non-protein and protein nitrogen. These results indicate that the brewery waste could be successfully used for a high scale production of amylases and proteases at a low cost.

Antioxidant ability of potato (Solanum tuberosum) peel extracts to inhibit soybean oil oxidation

Eur. J. Lipid Sci. Technol. (2016)

doi:10.1002/ejlt.201500419

Potato peels are an agro industrial waste of one of the major crops worldwide. However, the potential of potato peels as source of antioxidants in the food industry is not yet sufficiently known. In this work, the antioxidant effect of potato peel extract (PPE) on oxidative stability of soybean oil was evaluated. We found that the addition of low PPE concentrations to soybean oil at four different levels, expressed as chlorogenic acid concentrations (14.01, 20.37, and 31.94 ppm), affected lipid oxidation indices (peroxide, anisidine, and conjugated dienes values), fatty acid composition, and volatile compounds. Antioxidant effect increased with increasing dose extract. Inhibition percentages of hexanal production increased with the PPE concentration. In addition, low concentrations of PPE showed higher oxidation stability than control untreated samples. Overall, our study shows that low concentrations of PPE exhibited promising antioxidant activity to be applied over a wider range of products in the food industry.

Practical applications: The prevention of lipid oxidation during processing and storage of food products is of great concern in order to obtain products of high quality and health. Together with the fact that synthetic antioxidants may constitute a potential health hazard for consumers, interest in natural antioxidants and search on naturally occurring compounds with antioxidant activity has increased dramatically. The study of the antioxidant capacity of potato peel extracts to inhibit soybean oil oxidation provides information about an alternative antioxidant further are by-products of agro-industries and their use could represent a significant step toward maintaining an environmental balance.

Soil organic matter stabilization at the pluri-decadal scale: Insight from bare fallow soils with contrasting physicochemical properties and macrostructures

Geoderma 275 (2016) 48–54

http://dx.doi.org/10.1016/j.geoderma.2016.04.009

Physical protection is recognized as one of the main processes governing soil organic matter stabilization, but its importance over long time scales (decades to century) is being discussed. In this work, we used data from a long-term bare fallow experiment initiated in 1928 in Versailles (France) to investigate such process: given that no organic carbon inputs occurred since 1928, all the organic matter present had pluri-decadal to centennial mean residence times. The annual addition of mineral amendments (CaCO3 or KCl) produced contrasting superficial soil structures in some plots compared to non-amended plots. We hypothesized that a more aggregated and stable soil structure would likely be associated with higher organic carbon stocks. Stability of soil structure was quantified using three complementary tests: slow wetting to study macroaggregation, moderate dispersion compared to strong dispersion to study microaggregation. The CaCO3 plots had the highest macroaggregate stability, and KCl plots the lowest but microaggregation at the silt-size scale was similar for the three soils. After 79 years of bare fallow soil organic carbon stocks in the bulk soil were about 25% higher in the CaCO3 plots than in the KCl and reference plots. This relative increment was due to a higher amount of silt and clay-associated soil organic matter in CaCO3 plots, as a consequence of better physical or physicochemical protection at these scales, with a less important role of physical protection within stable macroaggregates.

Soil organic matter stabilization at the pluri-decadal scale: Insight from bare fallow soils with contrasting physicochemical properties and macrostructures

Geoderma 275 (2016) 48–54

http://dx.doi.org/10.1016/j.geoderma.2016.04.009

Physical protection is recognized as one of the main processes governing soil organic matter stabilization, but its importance over long time scales (decades to century) is being discussed. In this work, we used data from a long-term bare fallow experiment initiated in 1928 in Versailles (France) to investigate such process: given that no organic carbon inputs occurred since 1928, all the organic matter present had pluri-decadal to centennial mean residence times. The annual addition of mineral amendments (CaCO3 or KCl) produced contrasting superficial soil structures in some plots compared to non-amended plots. We hypothesized that a more aggregated and stable soil structure would likely be associated with higher organic carbon stocks. Stability of soil structure was quantified using three complementary tests: slow wetting to study macroaggregation, moderate dispersion compared to strong dispersion to study microaggregation. The CaCO3 plots had the highest macroaggregate stability, and KCl plots the lowest but microaggregation at the silt-size scale was similar for the three soils. After 79 years of bare fallow soil organic carbon stocks in the bulk soil were about 25% higher in the CaCO3 plots than in the KCl and reference plots. This relative increment was due to a higher amount of silt and clay-associated soil organic matter in CaCO3 plots, as a consequence of better physical or physicochemical protection at these scales, with a less important role of physical protection within stable macroaggregates.

Monitoring benthic microflora in river bed sediments: a case study in the Anllóns River (Spain)

Journal of Soils and Sediments (2016) 16, 1825–1839

DOI: 10.1007/s11368-016-1395-4

The objectives of this study were to investigate the abundance and composition of the superficial biofilm on the bed sediments of the Anllóns River (NW Spain), to evaluate the relationships between biochemical parameters and biological methods based on identification and counting, and to explore the relationships between biofilm growth and the properties of the sedimentary habitat, mainly the trophic state.

Bed sediment samples (0–5 cm) were collected in two different seasons (winter and summer) at four sampling sites along the river course. Physicochemical properties of pore waters and sediments were determined. Biological properties included the determination of dehydrogenase activity (DHA) and phytopigment (Chl a Chl b and total carotenoids) concentrations, as well as taxonomic identification. For taxonomic identification, two sampling methods were compared: the Pasteur pipette method and a mini-corer method. Total and relative algal abundances (TA and RA, respectively) and genus richness were calculated. The relationships between the different variables were examined using Pearson correlations and principal component analysis.

The main taxa belonged to Chlorophyta, Cyanophyta, Euglenophyta, and Heterokontophyta. The most abundant class was Bacillariophyceae, which represents >86 % of the total abundances in the superficial sediments. The highest total algal abundance and genus richness were observed in summer at the river mouth, where DHA and phytopigment concentrations were also the highest. The statistical analysis revealed positive correlations between TA and the biochemical parameters (DHA and phytopigments) as well as positive relationships of these three parameters with the physicochemical properties of the sediments, such as electrical conductivity, and the concentrations of fine particles, C, N, S, and total P.

The results of this study reveal the positive relationships between the biochemical properties (phytopigments and respiratory activity) and total algal abundances determined by taxonomic identification and counting. All of these properties presented evidence of a clear influence of the nutrients and organic matter contents of the sediments, pointing to the importance of the site conditions, particularly the trophic state, in the development of benthic microflora.

A biorefinery scheme for residual biomass using autohydrolysis and organosolv stages for oligomers and bioethanol production

Energy & Fuels

DOI: 10.1021/acs.energyfuels.6b00277

Straw is one of the main lignocellulosic waste produced during cereal crop cultivation. The abundance of barley straw makes it a good candidate for bioethanol production. This work deals with barley straw pretreatment by means of autohydrolysis in order to get xylooligosaccharides in the liquid phase, followed by an organosolv treatment using ethanol to increase the solid phase enzymatic susceptibility. Up to 17.4 g oligomers/L were obtained in the hydrothermal stage, in which practically all the cellulose and lignin remained in the solid phase. The solid phase from the hydrothermal-delignification was subjected to an experimental design in order to study the effect of pretreatment conditions in the bioethanol production, with values of solids concentrations in the range 7.7 to 20 weight % and values of enzyme loading in the range 14 FPU/g to 6 FPU/g. In the experiments carried out at a liquid to solid ratio = 4 g/g it is possible to obtain 31.6 g ethanol/L in just 9 h (corresponding to 100% ethanol conversion), with optimum results of 44.5 g ethanol/L in 46 h (90-93% glucose to ethanol conversion) and with a maximum concentration of 48.7 g ethanol/L in 89 h (79% conversion). The combination of a hydrothermal pretreatment (under conditions that lead to the recovery of high amounts of hemicellulosic by-products), followed by an organosolv treatment under mild conditions turns out to be suitable for second generation bioethanol production, applying a high solids loading, by means of fed-batch simultaneous saccharification and fermentation.

Characterization of virgin olive oils produced with autochthonous Galician varieties

Food Chemistry 212 ( 2016) 162–171

http://dx.doi.org/10.1016/j.foodchem.2016.05.135

The interest of Galician oil producers (NW Spain) in recovering the ancient autochthonous olive varieties Brava and Mansa has increased substantially in recent years. Virgin olive oils produced by co-crushing both varieties in two different proportions, reflecting the usual and most common practice adopted in this region, have gradually emerged for the production of virgin olive oils. Herein, the sensory and chemical characteristics of such oils were characterized by quality and genuineness-related parameters. The results of chemical analysis are discussed in terms of their effective contribution to the sensory profile, which suggests useful recommendations for olive oil producers to improve the quality of oils. Antioxidant compounds, together with aromas and coloured pigments were determined, and their contribution in determining the functional value and the sensory properties of oils was investigated. In general, given the high levels of phenolic compounds (ranging between 254 and 375 mg/kg oil), tocopherols (about 165 mg/kg oil) and carotenoids (10–12 mg/kg oil); these are oils with long stability, especially under dark storage conditions, because stability is reinforced with the contribution of chlorophylls (15–22 mg/kg oil). A major content of phenolic compounds, as well as a predominance of trans-2-hexen-1-al within odor-active compounds (from 897 to 1645 μg/kg oil), responsible for bitter sensory notes. This characterization allows to developing new antioxidant-rich and flavour-rich VOOs, when co-crushing with a higher proportion of Brava olives, satisfying the consumers’ demand in having access to more healthy dishes and peculiar sensory attributes.

Foto de Grupo - Septiembre de 2016

Investigadores del CIA en Vigo

Promoting sustainability in the mussel industry: mussel shell recycling to fight fluoride pollution

Journal of Cleaner Production, 131 (2016) 485–490

http://dx.doi.org/10.1016/j.jclepro.2016.04.154

Taking into account a background situation where some industrial activities greatly influence fluoride pollution, while other industries generate by-products that could be effective as fluoride bio-sorbents, and bearing in mind sustainability and environmental concern, batch-type experiments were performed to study fluoride sorption/desorption on individual (un-amended) and mussel shell-amended soils and materials. Specifically, the research focused on a forest soil, a vineyard soil, pyritic material, granitic material, and ground mussel shell, as well as on both soils and the pyritic and granitic materials amended with mussel shell. The main findings of the research indicate that the shell amendment clearly increased fluoride sorption in the pyritic material (reaching more than 90%), showing no effect as regards fluoride desorption from this material. The amendment caused a slight increase in fluoride sorption on forest soil, as well as a slight decrease in fluoride desorption from it. The un-amended vineyard soil and the un-amended granitic material had lower fluoride-retention capacity than the forest soil and pyritic material, and it did not change after amending with mussel shell. The mussel shell by itself showed the lowest fluoride-retention potential among the tested materials. As a conclusion, and focusing on applicability, these results can be useful to program the correct use of mussel shell amendment on soils and even on degraded environments with the aim of increasing fluoride retention or removal, thus decreasing risk of environmental pollution due to excessive fluoride concentrations in solid and/or liquid media, also facilitating recycling, sustainability and cleaner production in the mussel shell industry.

State of the art on public risk assessment of combined human exposure to multiple chemical contaminants

Trends in Food Science & Technology, 55 (2016) 11–28

http://dx.doi.org/10.1016/j.tifs.2016.06.011

Concern about the effects on health of exposure of combined chemicals present in food, air or water are increasing nowadays. However, mechanism and effects of combined chemical contaminants are still poorly know.

This review deals with the variety of routes of these chemicals when enter the human body. The gaol is the development of a mechanism-based and quantitative framework for risk assessment to estimate the impact on human health and prevent exposure to multiple chemicals.

It has been shown that new studies should be developed taking into account cumulative effect of these substances and different tiers as external exposition, dietary exposition, lifestyle, age and economic factors. New techniques must also be implemented, mainly “omic” techniques, bioassay systems, mathematical modelling, quantitative structure-activity relationship models, and threshold of toxicological concern to develop databases. In conclusion, several programs should continuously be developed by different health agencies to have a better understanding of the effect of these substances and to develop a unified policy.

Kinetic modelling of mancozeb hydrolysis and photolysis to ethylenethiourea and other by-products in water

Water Research 102 (2016) 561–571

http://dx.doi.org/10.1016/j.watres.2016.07.006

The aim of this study was to propose kinetic models suitable for reproducing and predicting mancozeb (Mz) conversion to by-products as a function of the operational conditions. The main factors (pH, temperature and light) potentially affecting the mancozeb degradation in aqueous models were studied by a multifactorial screening design. In addition, the response surface methodology (RSM) was applied to evaluate the interactive effects of these factors on ethylenethiourea (ETU) formation. The response surface revealed that the best degradation conditions to minimize mancozeb conversion to ETU were low pH (2), low temperature (25 °C) and darkness. Under these conditions, the percentage of mancozeb remained in the solution at 72 h was approximately 10% of the initial concentration and the percentage of ETU conversion was 5.4%. However, according to the model, in surface waters under typical environmental conditions (pH 8, 25 °C and light) the percentage of mancozeb conversion to ETU would be about 17.5%. The proposed model provides a satisfactory interpretation of the experimental data obtained during the hydrolysis of mancozeb.

Valorization of biosorbent obtained from a forestry waste: Competitive adsorption, desorption and transport of Cd, Cu, Ni, Pb and Zn

Ecotoxicology and Environmental Safety, 131(2016) 118–126

http://dx.doi.org/10.1016/j.ecoenv.2016.05.007

Bark from Pinus pinaster is one of the most abundant forestry wastes in Europe, and among the proposed technologies for its reutilization, the removal of heavy metals from wastewater has been gaining increasing attention. In this work, we have studied the performance of pine bark for heavy metal biosorption on competitive systems. Pb, Cu, Ni, Zn and Cd sorption and desorption at equilibrium were studied in batch experiments, whereas transport was studied in column experiments. Batch experiments were performed adding simultaneously different concentrations (0.08–3.15 mM) of two or more metals in solution to pine bark samples. Column experiments were performed with 10 mM solutions of two metals or a 5 mM solution of the five metals. In general, the results under competitive conditions were different to those obtained in monoelemental experiments. The multi-metal batch experiments showed the adsorption sequence Pb≈Cu>Cd>Zn>Ni for lower metal doses, Pb>Cu>Cd>Zn>Ni for intermediate doses, and Pb>Cu>Cd≈Zn≈Ni for high metal doses. Desorption followed the sequence Pb<Cd<Cu<Zn<Ni for the lowest metal doses, and Pb<Cu<Zn<Cd<Ni for the highest ones. The bi-metal batch experiments indicated that Cu and Pb suffered the highest retention, with high capacity to displace Cd, Ni and Zn from adsorption sites on pine bark. The transport experiments produced comparable results to those obtained in the batch experiments, with pine bark retention capacity following the sequence Pb>Cu>Zn>Cd>Ni. The presence of a second metal affected the transport of all the elements studied except Pb, and confirmed the strong influence of Pb and Cu on the retention of the other metals. These results can help to appropriately design decontamination systems using this forestry waste.

Phosphorus retention on forest and vineyard soil samples, mussel shell, pine-sawdust, and on pyritic, granitic and waste materials

Geoderma, 280 (2016) 8–13

http://dx.doi.org/10.1016/j.geoderma.2016.06.003

Focusing on P, we used batch-type experiments to study P retention on various materials: a forest soil sample, a vineyard soil sample, finely and coarsely ground mussel shell, pine-sawdust, pyritic material, granitic material, mussel shell calcination ash, slate processing fines, and three different mixtures that included three components: sewage sludge, mussel shell ash, and calcined mussel shell or pine wood ash. The pyritic material and the mussel shell ash showed the highest P retention capacity, reaching > 95%. The lowest P retention (< 60%) corresponded to the pine-sawdust and slate processing fines. Data fitted satisfactorily to the Freundlich model, unless in the case of pine-sawdust and slate fines; however, only forest and vineyard soil samples can be satisfactorily adjusted to the Langmuir model. These results could be useful to program appropriate management practices, especially when focusing on controlling P concentrations in different environmental compartments, as well as to correctly recycle the by-products and waste materials assayed.

Competitive and non-competitive cadmium, copper and lead sorption/desorption on wheat straw affecting sustainability in vineyards

Journal of Cleaner Production

http://dx.doi.org/10.1016/j.jclepro.2016.09.021

The novelty of this work lies on the consideration of wheat straw to retain Cu and other heavy metals in vineyards, in addition to its known potential to decrease erosion, thus facilitating the growth of new vine plants and contributing to sustainability in vineyard production. In this study we used batch-type experiments to investigate Cd, Cu and Pb competitive and non-competitive sorption/desorption on wheat straw. In non-competitive experiments, sorption sequence was Pb > Cd > Cu when the lowest molar concentrations (0.5 mmol L−1) were added, and Pb > Cu > Cd when the highest molar concentrations (6.0 mmol L−1) were added. Sorption curves indicated clearly higher sorption for Pb, lower initial sorption in the case of Cu, and certain trend to saturation of sorption sites for Cd. Data showed good adjustment to the Langmuir model just for Cd, whereas the Freundlich equation fitted well for all three metals. Desorption rates were low, in the order Pb < Cd < Cu. In the competitive experiment, the sorption sequence was Pb > Cu > Cd. The results indicate that competition clearly affected to Cd sorption, especially when the highest concentrations (6 mmol L−1) of the three heavy metals were added. The highest percentage of desorption in the competitive system corresponded to Cd, whereas Pb and Cu experienced clearly lower release. Comparing competitive and non-competitive experiments, Pb sorption was equivalent in the non-competitive and competitive trials, Cu sorption was slightly higher in the non-competitive than in the competitive experiment, and Cd sorption was clearly higher in the non-competitive trial. Percentage desorption decreased for Pb and for Cu in the competitive trial, whereas it was clearly higher for Cd in the competitive than in the non-competitive experiment. The overall results indicate that Pb, Cu and Cd can be retained by wheat straw (especially Cu and Pb), thus decreasing risks of pollution, which could be used to treat polluted waters, and could also give additional value to wheat straw mulching used to protect vineyards from erosion and Cu (and other heavy metals) pollution, thus contributing to sustainability in this productive sector.

Biological activities and novel applications of chalcones

Planta Daninha

http://dx.doi.org/10.1590/S0100-83582016340300022

This review provides information on the biological activities of chalcones (whether natural or synthetic derivatives) on different organisms, as well as an overview of the functions and possible new applications of these plant secondary metabolites on crop protection, as eco-friendly pesticides and weed control agents. Naturally occurring chalcones have been used in traditional medicine for many years; however, recent scientific advances have shown that these molecules have a broad range of biological activities in a variety of organisms. A review on the major sources of chalcones and the main molecular events involved in the modes of action of these natural products is achieved. Chalcones are molecules with a broad spectrum of biological activities, which are of great interest in agriculture to control weeds and unwanted pests.

Foto de Grupo - Septiembre de 2016

Investigadores del CIA en Ourense

Feruloyl esterase production by Aspergillus terreus CECT 2808 and subsequent application to enzymatic hydrolysis

Enzyme and Microbial Technology, 91 (2016) 52–58

http://dx.doi.org/10.1016/j.enzmictec.2016.05.011

Ferulic acid esterases (FAE) were produced by Aspergillus terreus CECT 2808 from vine trimming shoots (VTS) and corn cob. Later, the fungal extracts thus obtained were used to enzymatically release ferulic acid (FA) from both substrates. Our findings showed a higher FAE activity in the enzymatic extracts produced on corn cob (0.070 ± 0.004 U/mL). Nevertheless, the enzymatic extracts produced on VTS demonstrated a better performance for FA release from both corn cob (2.05 ± 0.01 mg/g) and VTS (0.19 ± 0.003 mg/g). This result was probably because of the higher xylanase/FAE ratio determined in VTS extract. Therefore, an additional assay was carried out by supplementing corn cob extract with a commercial xylanase to test the influence of FAE/xylanase ratio in FA release. The results revealed the relevance of the FAE/xylanase ratio for an optimal FA release.

Carbon fractionation in a mine soil amended with compost and biochar and vegetated with Brassica juncea L

Journal of Geochemical Exploration

Volume 169, October 2016, Pages 137–143

http://dx.doi.org/10.1016/j.gexplo.2016.07.021

The aim of this study was to evaluate the effect of the application of compost and biochar as soil amendments and planting of Brassica juncea L. to improve soil carbon fractions in a copper mine soil. A greenhouse experiment was carried out for 3 months amending the mine soil with increasing proportions of compost and biochar mixture (20, 40, 80 and 100%) and planting Brassica juncea L. The results showed that the addition of amendments increased soil pH from 2.7 to 8.66, TC from undetectable levels to 149 g kg− 1, SOC from undetectable levels to 128 g kg− 1 and TN from undetectable levels to 11.13 g kg− 1. Organic amending also increased DOC (dissolved organic carbon) from undetectable levels to 25.56 g kg− 1, FOM (carbon in the free organic matter) from undetectable levels to 38.04 g kg− 1, FAP (carbon in fulvic acids removed with phosphoric acid) from undetectable levels to 15.57 g kg− 1, as well as increased the humification ratio, the humification index, the polymerisation rate and the organic carbon in the humified fractions (humic acids, fulvic acids and humin). Soils amended and vegetated with Brassica juncea showed lower values for FOM and FAP and higher values for humification ratio and polymerisation rate than the amended not-vegetated soils. Therefore, the combination of compost and biochar as soil amendment can be considered an efficient treatment to improve soil carbon fractions, making it suitable for a field scale application.

Lipid characteristics of dry-cured “Tocino” during the manufacturing process. Effects of salting intensity and ripening temperature

Journal of Food Composition and Analysis, 52 (2016) 33–43

http://dx.doi.org/10.1016/j.jfca.2016.07.005

The fatty acid composition, the lipid characteristics and the colour parameters of Tocino, a salted and ripened meat product made from subcutaneous backfat from pig, were studied throughout manufacturing of the product. The effects of the ripening temperature and of the duration of the salting process were also studied. Ripening process caused a significant (P < 0.001) decrease in the total and some individual polyunsaturated fatty acids (C18:2n-6, C18:3n-3, C20:2n-6, C20:3n-6, C20:4n-6, and C20:3n-3), particularly in the polar lipid fraction (total polyunsaturated fatty acids descended from 13.6 to 3.5% of total methyl esters). Increased ripening temperature (from 8 to 12 °C) and longer duration of salting (from 2 to 4 days) caused a significantly greater decrease in the content of polyunsaturated fatty acids. The nutritional and health index values indicated that Tocino is not a healthy product. During the ripening stage, Tocino underwent moderate lipolysis and very intense lipid oxidation (final values of 3.57–5.09 mg KOH/g of fat and 0.84–1.16 mg malondialdehyde/kg). Increasing the ripening temperature significantly increased (P < 0.001) both lipolysis and fat oxidation, while increasing the duration of salting only had a significant positive effect on oxidation processes. Longer ripening times led to a significant increase (P < 0.001) in the b* values (from 8.81 to 18.7–23.7) and significant decreases in the a* (from 7.10 to −3.31 – −4.04) and L* (from 81.5 to 66.4–70.2) values.

Effect of high pressure treatment on the structural, mechanical and rheological properties of glucomannan gels

Food Hydrocolloids, 60 (2016) 437–444

http://dx.doi.org/10.1016/j.foodhyd.2016.04.015

The influence of high hydrostatic pressure (HHP) of 100 (C100), 200 (C200), 400 (C400) and 600 MPa (C600) on the structural, physicochemical, and thermo-rheological properties of aqueous glucomannan dispersions (AGD) was studied. Each AGD was prepared with a 5% concentration of deacetylated glucomannan (GM) at pH = 11 for use in the preparation of restructured fish products. The control (0 MPa) AGD (C0) exhibited a partially crystalline GM network with a glass transition temperature (Tg) of ∼75 °C. C0 gels at 25 °C were rigid, with high breaking force (BF), fracture constant (Kf) and complex modulus (G*) and low tanδ values due to the large number of physical junctions produced by complete deacetylation of the GM chains. This structural response was reflected in high water binding capacity (WBC) and colour (L*) and low cooking loss (CL). Specifically, 200 MPa reduced close packing ability in the crystalline regions, evidenced in the lower Tg∼65 °C and resulting in lower gel strength (S), Kf, G* and a higher viscous component (high tanδ), thus reducing the L* value. Conversely, 600 MPa increased the degree of cross-linking in C600, reinforcing the number and extent of crystalline regions, resulting in the broadening of the O–H stretching band in the FT-IR spectrum and producing a thermoset physical network with no glass transition region. Thus, C600 gel was firmer (higher G*) with greater S, and less flexible (lower strain amplitude-γmax). Consequently, depending on the textural properties desired in the final restructured fish product, the most appropriate pressure would be 200 MPa for softer final gels and 600 MPa for firmer and less deformable gels.

Combined alkali and hydrothermal pretreatments for oat straw valorization within a biorefinery concept

Bioresource Technology

http://dx.doi.org/10.1016/j.biortech.2016.08.077

The aim of this work was the evaluation of lime pretreatment combined or not with previous step of autohydrolysis for oat straw valorization. Under selected conditions of lime pretreatment, 96% of glucan and 77% of xylan were recovered and 42% of delignification was achieved. Xylose fermentation to ethanol by metabolic engineered Saccharomyces cerevisiae (MEC1133) strain improved the ethanol production by 22% achieving 41 g/L. Alternatively, first step of autohydrolysis (S0=4.22) allowed a high oligosaccharides recovery (68%) and subsequent lime pretreatment attained a 57% of delignification and 99% of glucan to glucose conversion. Oat straw processed by autohydrolysis and lime pretreatment reached the maximal ethanol concentration (50 g/L). Both strategies led to oat straw valorization into bioethanol, oligosaccharides and lignin indicating that these pretreatments are adequate as a first stage within an oat straw biorefinery.

Production and characterization of a novel distilled alcoholic beverage produced from blueberry (Vaccinium corymbosum L.)

Fruits, 2016, vol. 71(4), 215-220

http://dx.doi.org/10.1051/fruits/2016013

The cultivation of underutilized berries and the process production of high-value-added products, such as fruit-based spirits, could have a beneficial effect on the economy of disadvantaged rural mountain areas of Spain. However, production of a distilled alcoholic beverage from the blueberry has not been reported before. The pulp of blueberries var. Bluecrop was fermented with Saccharomyces cerevisiae IFI83, distilled by using a steam drag distillation system and the volatile compounds were determined by gas chromatography. In the distillate obtained, the mean concentrations of ethanol (45.3 mL 100 mL-1 distillate), volatile substances (317.1 g hL-1 absolute alcohol) and methanol (261.0 g hL-1 absolute alcohol) were in accordance with the specifications that the European Council (Regulation 110/2008) fixed for these compounds. In addition, the ratios [3-methyl-1-butanol/2-methyl-1-propanol] and [2-methyl-1-propanol/1-propanol] were 2.60 and 1.34, respectively, indicating that the distilled alcoholic beverage has a good organoleptic quality. The results suggest that blueberry can be successfully used for the production of a novel spirit with a good sensory quality that is safe for the consumers.

Loss of Gravitropism in Farnesene-Treated Arabidopsis Is Due to Microtubule Malformations Related to Hormonal and ROS Unbalance

PLOS ONE

http://journals.plos.org/

Mode of action of farnesene, a volatile sesquiterpene commonly found in the essential oils of several plants, was deeply studied on the model species Arabidopsis thaliana. The effects of farnesene on the Arabidopsis root morphology were evaluated by different microscopic techniques. As well, microtubules immunolabeling, phytohormone measurements and ROS staining helped us to elucidate the single or multi-modes of action of this sesquiterpene on plant metabolism. Farnesene-treated roots showed a strong growth inhibition and marked modifications on morphology, important tissue alterations, cellular damages and anisotropic growth. Left-handed growth of farnesene-treated roots, reverted by taxol (a known microtubule stabilizer), was related to microtubule condensation and disorganization. As well, the inhibition of primary root growth, lateral root number, lateral root length, and both root hairs length and density could be explained by the strong increment in ethylene production and auxin content detected in farnesene-treated seedlings. Microtubule alteration and hormonal unbalance appear as important components in the mode of action of farnesene and confirm the strong phytotoxic potential of this sesquiterpene.

Carbohydrate Polymers, 146 (2016) 20–25

http://dx.doi.org/10.1016/j.carbpol.2016.03.049

Eucalyptus globulus wood samples were treated with hot, compressed water to separate hemicelluloses (as soluble saccharides) from a solid phase mainly made up of cellulose and lignin. The liquid phase was dehydrated, and the resulting solids (containing pentoses as well as poly- and oligo- saccharides made up of pentoses) were dissolved and reacted in media containing an Acidic Ionic Liquid (1-butyl-3-methylimidazolium hydrogen sulfate) and a co-solvent (dioxane). The effects of the reaction time on the product distribution were studied at temperatures in the range 120–170 °C for reaction times up to 8 h, and operational conditions leading to 59.1% conversion of the potential substrates (including pentoses and pentose structural units in oligo- and poly- saccharides) into furfural were identified.

Lithological and land-use based assessment of heavy metal pollution in soils surrounding a cement plant in SW Europe

Science of The Total Environment 562, 2016, 179–190

http://dx.doi.org/10.1016/j.scitotenv.2016.03.198

We study the influence of phasing out a cement plant on the heavy metal (Hg, Pb and Cr) content in the surrounding soils, taking into account factors often neglected, such as contributions due to local lithology or land use. The range of total Hg was 10–144 µg kg− 1, reaching up to 41 and 145 mg kg− 1 for total contents of Pb and Cr, respectively. Forest soils showed higher concentration of Hg than prairie soils, indicating the importance of land use on the accumulation of volatile heavy metals in soils. In forest soils, total Hg showed a trend to decrease with soil depth, whereas in prairie soils the vertical pattern of heavy metal concentrations was quite homogeneous. In most cases, the distance to the cement plant was not a factor of influence in the soils content of the analyzed heavy metals. Total Pb and Cr contents in soils nearby the cement plant were quite similar to those found in the local lithology, resulting in enrichment factor values (EF's) below 2. This suggests that soil parent material is the main source of these heavy metals in the studied soils, while the contribution of the cement plant to Pb and Cr soil pollution was almost negligible. On the contrary, the soils surrounding the cement plant accumulate a significant amount of Hg, compared to the underlying lithology. This was especially noticeable in forest soils, where Hg EF achieved values up to 36. These results are of relevance, bearing in mind that Hg accumulation in soils may be an issue of environmental concern, particularly in prairie soils, where temporal flooding can favor Hg transformation to highly toxic methyl-Hg. In addition, the concurrence of acid soils and total-Cr concentrations in the range of those considered phytotoxic should be also stressed.

Adsorption and desorption kinetics and phosphorus hysteresis in highly weathered soil by stirred flow chamber experiments

Soil and Tillage Research, 162 (2016) 46–54

http://dx.doi.org/10.1016/j.still.2016.04.018

Soils with a high weathering degree present great difficulties for management of phosphorus (P) fertilization due to their high adsorption rates. The magnitude and velocity of the P retention phenomena in these soils is still poorly understood and has great importance to effective management of soil phosphorus. The objective of this study was to evaluate the adsorption and desorption kinetics and phosphorus adsorption irreversibility (hysteresis) in highly weathered soils. For this purpose, we selected four soils: Xanthic Ferralsol-1 (FR-1), Xanthic Ferralsol-2 (FR-2), Rhodic Ferralsol (FR-3) and Hortic Anthrosol “Terra Preta de Índio” (AT). Adsorption followed by desorption experiments in Stirred flow chamber were performed. From obtained data, parameters related to P kinetics were estimated, considering the presence of two types of adsorption and desorption sites (fast and slow), estimating also the hysteresis index. It was observed that FR-2 and FR-3 showed higher P adsorption and most of the adsorbed P was at first 100 min of evaluation. Furthermore, in FR-1, FR-2 and FR-3, approximately half of adsorption occurred by rapid sites (F which is the fraction of fast sites ranging from 0.45 to 0.55), while AT adsorption was lower (qmax = 48.95 mg kg−1) and occurred slower (F = 0.33). In FR-2 and FR-3, between 71 and 72% of adsorbed P was not desorbed, while in AT, only 11% of P was irreversibly adsorbed. The P kinetics in highly weathered soils proved to be a process governed by the fast sites on adsorption and slow sites on desorption, resulting in high levels of hysteresis.

Dernières nouvelles de 42 vieilles parcelles Indicateurs d’évolutions pédologiques infra-centenaires en Néoluvisol de lœss nu, sous contrainte d’applications continues de matières fertilisantes

Étude et Gestion des Sols, 23, 2016, 143-162

Ce travail présente un bilan des impacts de 85 ans d’apports d’engrais chimiques N, P, K, d’amendements basiques et organiques sur la composition et les propriétés d’un Néoluvisol de lœss, en comparaison à des situations témoins sans apport. Cette expérimentation de longue durée est menée depuis 1928 en sol nu dans le dispositif des 42 parcelles à l’Inra de Versailles. Le bilan repose sur les résultats analytiques d’échantillons collectés en 2014 dans l’ensemble des horizons de surface. Les résultats sont confrontés à des données disponibles du sol initial de 1928. L’objectif est de préciser la nature et l’ampleur des évolutions physicochimiques, induites en moins d’un siècle, et d’identifier les processus pédologiques qui en sont à l’origine.

En absence d’entrée de matières organiques (MO), de forts contrastes s’observent en fonction de la nature des apports minéraux, mais aussi dans les parcelles témoins : en 2014, d’une parcelle à une autre, l’écart maximal de pH est de 5,3 unités (3,5-8,8) et la CEC varie de 5,2 à 14,4 cmol+/kg. La garniture cationique varie de plus de 98 % de Ca échangeable dans les sols chaulés, à plus de 96 % d’Al échangeable dans les sols acides. Le carbone organique a perdu 50 à 75 % de la valeur initiale en 1928, et les teneurs en argile s’étendent entre 13 et 20 %. Des teneurs significatives de Mnéch s’observent dans les sols denses, alors que Feéch est détectable prioritairement dans les sols acides. Par contre, sous amendement de fumier, l’ambiance physicochimique est très différente, notamment par l’abondance de C organique (43-50 g/kg) et une forte valeur de la CEC, supérieure à 22 cmol+/kg.

La nature, l’ampleur et la diversité des propriétés physicochimiques enregistrés dans les horizons de surface des sols des 42 parcelles en 2014 témoignent de différents processus pédologiques en jeu, actuels ou dans le passé. Dans les sols témoins, sous la seule contrainte de la minéralisation progressive des MO et des conditions atmosphériques, les propriétés et la composition ont considérablement changé : une acidification de 1-1,5 unités de pH, la lixiviation d’une proportion notable de cations bivalents et l’apparition de quantités significatives d’Al échangeable sur le complexe d’échange, une baisse de la CEC et une perte d’argile de 2 à 3 %. La migration d’argile, l’argilluviation, processus caractéristique dans les luvisols, apparaît amplifiée sous traitements ‘monovalents’, notamment sous apport de Na où la perte d’argile par lessivage peut atteindre jusqu’à 5 à 6 %. Sous apport de K, la perte d’argile est moindre, liée à un processus d’illitisation des particules de smectite par rétrogradation du K. De plus, les apports de phosphate naturel ou de superphosphate semblent également favoriser la migration d’argile, alors que les amendements basiques et de fumier limitent, voire stoppent le processus. Dans les traitements ‘acides’, sous apports d’engrais ammoniacaux ou de sang desséché, les cations échangeables initiaux (Ca, Mg, K, Na) ont été quasi-totalement lixiviés, et remplacés par l’Al. La forte aluminisation du milieu implique un processus de dissolution minérale, affectant en premier lieu les argiles fines (smectites). Les faibles valeurs de la CEC illustrent la perte notable de charges fixes liée à la dissolution partielle des smectites. Néanmoins, l’impact de l’altération en milieu acide sur la granulométrie apparait négligeable, car la teneur en argile dans les sols acides reste inchangée par rapport à 1929. Deux pistes sont envisagées pour expliquer ce constat : un processus de microdivision par l’altération de minéraux phyllosilicatés de taille limoneuse fine et leur transformation en particules argileuses, ou alors un processus de néoformation de phases secondaires à partir de Si, Al et/ou Fe libérés par dissolution d’argiles fines en milieu acide. Enfin, un processus d’agrégation à l’échelle des particules d’argile par le développement de liaisons fortes entre les particules d’argile et des phosphates-Al (ou –Fe) formés en milieu très acide est suspecté dans les sols sous phosphate d’ammoniaque conduisant à la sous-estimation de la fraction < 2 μm lors d’analyses granulométriques courantes.

La palette très étendue de propriétés physicochimiques des horizons de surface dans les 42 parcelles souligne un laps de temps court en pédologie pour leurs changements, d’ordre infra-centenaire. Pour assimiler ces changements opérés en surface au développement de processus pédologiques, il est nécessaire à la fois de suivre l’ampleur et la chronologie des évolutions par l’analyse d’échantillons de la collection historique et d’étendre l’étude des impacts aux horizons E, BT, et C profonds. Ces travaux sont actuellement en cours.

Effects of different cooking methods on some chemical and sensory properties of Galega kale

International Journal of Food Science and Technology

DOI: 10.1111/ijfs.13181

Kale (Brassica oleracea L. var. acephala) is rich in bioactive phytochemicals such as phenolic compounds and vitamins. However, cooking the plants can cause important changes in composition. The objective of this study was to investigate the effect of some domestic cooking processes (boiling, steaming, microwaving and pressure cooking) on several quality parameters of Galega kale. Boiling had the strongest effect on the antioxidant capacity (the IC50 was four times higher than in the fresh sample), total phenolics (losses of 76.4–77.9%) and colour (ΔE = 17.79–19.12). Microwaving caused the greatest loss of soluble solids (80.8–82.2%). Steaming seems to be the best method for retaining the nutrient and antioxidant capacity of kale (100% ash, 71–77.5% soluble solids, 100% antioxidant capacity, 67–71% total phenolics, 62–71% chlorophyll). However, steamed kale was awarded the lowest sensory scores, indicating the difficulty in reconciling nutritional value and sensorial quality. Use of discriminant statistical techniques enabled the classification of 100% of samples.

Optimization of the process of aromatic and medicinal plant maceration in grape marc distillates to obtain herbal liqueurs and spirits

Journal of the Science of Food and Agriculture

DOI: 10.1002/jsfa.7822

Herbal liqueurs are alcoholic beverages produced by the maceration or distillation of aromatic and medicinal plants in alcohol, and are also highly valued for their medicinal properties. The process conditions, as well as the number and quantity of the plants employed, will have a great influence on the quality of the liqueur obtained. The aim of this research was to optimize these important variables.

A Box–Benhken experimental design was used to evaluate the independent variables: alcohol content, amount of plant and time during the experimental maceration of plants in grape marc distillate. Four plants were assessed, with the main compound of each plant representing the dependent variable evaluated with respect to following the evolution of the maceration process. Bisabolol oxide A in Matricaria recutita L., linalool in Coriander sativum L. and eucalyptol in Eucalyptus globulus Labill. were quantified using a gas chromatography-flame ionization detector. Glycyrrhizic acid in Glycyrrhiza glabra L was determined using a high-performance liquid chromatography-diode array detector. Other dependent variables were also evaluated: total phenolic content, color parameters and consumer preference (i.e. appearance).

The experimental designs allowed the selection of the optimal maceration conditions for each parameter, including the preference score of consumers: 70% (v/v) of ethanol, 40 g L−1 plant concentration and a maceration process of 3 weeks. 

Second-generation bioethanol of hydrothermally pretreated stover biomass from maize genotypes

Biomass and Bioenergy, 90 (2016) 42–49

http://dx.doi.org/10.1016/j.biombioe.2016.03.029

Twelve maize genotypes, were agronomically evaluated and their stover hydrothermally pretreated in a temperature range of 210–225 °C to assess the effects of genotype and pretreatment severity on stover recalcitrance toward bioethanol conversion. Maize genotypes exhibited significant variation for biomass yield and all agronomic evaluated, while among all cell wall constituents measured in the unpretreated stover, only ash content showed differences among genotypes. The pretreatment severities assayed impacted most stover compositional traits, and the glucose recovered after enzymatic hydrolysis displayed a similar profile among genotypes with similar genetic background. Harsher pretreatment conditions maximized the potential cellulosic bioethanol production (208–239 L/t), while the mildest maximized the bioethanol from the hemicellulosic hydrolysates (137–175 L/t). Consequently, when both pentose and hexose sugars were considered, the total potential bioethanol produced at the lowest and highest pretreatment temperatures was similar in all genotypes (292–358 L/t), indicating that the lowest temperature (210 °C) was the optimal among all assayed. Importantly, the ranking of genotypes for bioethanol yield (L/ha) closely resembled the ranking for stover yield (t/ha), indicating that breeding for biomass yield would increase the bioethanol production per hectare regardless of the manufacturing process. Similarly, the genetic regulation of corn stover moisture is possible and relevant for efficient energy production as biomass moisture has a potential impact on stover transportation, storage and processing requirements. Overall, these results indicate that local landrace populations are important genetic resources to improve cultivated crops, and that simultaneous breeding for production of grain and stover bioethanol is possible in corn.

F sorption/desorption on two soils and on different by-products and waste materials

Environmental Science and Pollution Research (2016) 23, 14676–14685

DOI: 10.1007/s11356-016-6959-8

We used batch-type experiments to study F sorption/desorption on a forest soil, a vineyard soil, pyritic material, granitic material, finely and coarsely ground mussel shell, mussel shell calcination ash, oak wood ash, pine-sawdust, slate processing fines, and three different mixtures that included three components: sewage sludge, mussel shell ash, and calcined mussel shell or pine wood ash. The three waste mixtures, forest soil, pyritic material, and shell ash showed high sorption capacity (73–91 % of added F) and low desorption, even when 100 mg F L−1 was added. All these materials (and to a lower extent wood ash) could be useful to remove F from polluted media (as certain soils, dumping sites, and contaminated waters). The vineyard soil, the granitic material, mussel shell, slate fines, and pine-sawdust were less effective in F removal. In most cases, sorption data fitted better to the Freundlich than to the Langmuir equation. These results can be useful to program the correct management of the soils, by-products, and waste materials assayed, mostly in situations where F concentrations are excessive and F removal should be promoted.