Bioconversion of potatoes residues or surplus potatoes to ethanol under non axenic conditions [abstract]

Biofuels can offer an alternative to fossil fuels in the context of climate change and fossil reserves depletion. With 3 million tons of potatoes produced in 2007 and a high yield per hectare of 47 tons, Belgium is the 19th largest producer in the world. The residual and surplus potatoes could be used to produce bioethanol by fermentation. We examined the feasibility of a simple ethanol fermentation process under non axenic conditions. The substrate was pretreated with commercial amylases or by adding as low as 10% FM (Fresh Matter) barley malt. It was then fermented with Saccharomyces cerevisiae. Ethanol and volatile fatty acids were analyzed by GC-FID and soluble sugars were analyzed with the Anthrone method. Starch from potatoes was hydrolyzed to soluble sugars. Hydrolysis seems to continue with 10% FM of barley malt after 48 h while the hydrolysis stopped or decelerated with commercial enzymes. With 10% FM of malt, 3 h of hydrolysis and 7 days of fermentation, an ethanol concentration of 42 g.l-1 was obtained and the conversion yield was 139 gethanol.kg-1 DM. The fermentation conversion yield of soluble sugars to ethanol was > 82% and the endogenous competition was limited. However, starch hydrolyzing seems to be a limiting step under the conditions tested. Commercial enzymes did not provide better results under the same conditions

Systemic analysis of production scenarios for bioethanol produced from ligno-cellulosic biomass [abstract]

Defining alternatives for non-renewable energy sources constitutes a priority to the development of our societies. One of these alternatives is biofuels production starting from energy crops, agricultural wastes, forest products or wastes. In this context, a "second generation" biofuels production, aiming at utilizing the whole plant, including ligno-cellulosic (hemicelluloses, cellulose, lignin) fractions (Ogier et al., 1999) that are not used for human food, would allow the reduction of the drawbacks of bioethanol production (Schoeling, 2007). However, numerous technical, economical, ethical and environmental questions are still pending. One of the aims of the BioEtha2 project, directed by the Walloon Agricultural Research Centre, is to define the position of bioethanol produced from ligno-cellulosic biomass among the different renewable energy alternatives that could be developed in Wallonia towards 2020. With this aim, and in order to answer the numerous questions in this field, the project aims at using tools and methods coming from the concept of "forecasting scenarios" (Sebillotte, 2002; Slegten et al., 2007; For-learn, 2008). This concept, based on a contemporary reality, aims to explore different possible scenarios for the future development of alternative sources of energy production. The principle is to evaluate, explore, possible futures of the studied problematic, through the establishment of possible evolution trajectories. We contribute to this prospective through a systemic approach (Vanloqueren, 2007) that allows lightening the existing interactions within the system "ligno-cellulosic biomass chain" without isolating it from its environment. We explain and sketch the two contexts needed to identify primary stakes. The global context includes inter-dependant and auto-regulating fields such as society, politics, technology and economy. These four fields influence each part of the "chain" with specific tools. However, the interest and possible action fields lay within the intermediary context representing the "resources" such as agriculture, forestry, "driving" elements such as mobility, mediation elements such as territories and environment and concurrent elements such as non-cellulosic biomass, the energy mix and the non-energy valorization

La divinyl éther synthase de plantes

La divinyl éther synthase, une enzyme appartenant à la voie de la lipoxygénase, transforme chez les tubercules de pomme de terre les 9-hydroperoxydes d’acides gras en acides colneléique et colnelénique, deux éthers divinyliques d’acides gras. L’enzyme n’a été mise en évidence que dans un nombre assez limité de végétaux cependant forts différents. Outre dans les tubercules de pomme de terre, on rencontre également cette enzyme dans les racines de tomate, les bulbes d’ail, les plantes de tabac ainsi que dans des algues marines. L’enzyme, membranaire, serait localisée dans la fraction microsomique. Chez le tubercule de pomme de terre, l’enzyme possède une masse molaire supérieure à 100.000 Da, un pH optimum de 9 et une spécificité élevée pour les 9-hydroperoxydes d’acides gras en tant que substrat. Des études menées à l’aide de produits marqués ont permis d’élucider le mécanisme réactionnel. Les acides colneléique et colnelénique peuvent être dégradés enzymatiquement ou non en aldéhydes et oxo-acides. Il est à noter que ces mêmes composés sont formés par l’action de l’hydroperoxyde lyase sur les 9-hydroperoxydes d’acides gras. Comme pour beaucoup d’autres enzymes de la voie de la lipoxygénase, l’implication des produits réactionnels de la divinyl éther synthase dans la résistance aux agents pathogènes a été suggérée. On a pu, en effet , corréler la teneur en acides colnelénique et colneléique avec la résistance de Solanum tuberosum à Phytophthora infestans.Divinyl ether synthase, an enzyme of the lipoxygenase pathway transforms, in potato tubers, 9-hydroperoxides of fatty acids into colneleic and colnelenic acid, two divinyl ethers of fatty acids. The enzyme has been described in a limited number of quite different plants. The enzyme has also been detected in tomato roots, garlic bulbs, tobacco plants and in marine algae. The enzyme is bound to membranes and is located in the microsomal fraction. The molecular weight of the enzyme exceeds 100,000 Da, its optimal pH is around 9 and its high specificity for 9-hydroperoxides as substrate is described. The reactional mechanism has been elucidated using radio-labelled molecules. Colneleic and colnelenic acid can be degraded enzymatically or not into aldehydes and oxo-acids. Those last compounds are also formed by the action of hydroperoxide lyase on 9-hydroperoxides of fatty acids. As other enzymes of the lipoxygenase pathway, reaction products of divinyl ether synthase are involved in pathogenic resistance. Colneleic and colnelenic acid content in potato plants has been corelated with resistance to Phytophthora infestans

Validation de méthodes performantes d'analyse globale des éléments chimiques (dont la XRF : Spectrométrie de Fluorescence X), appliquées aux terres cultivées et aux intrants valorisables en agriculture

Rapport fina

Fond géochimique des sols : intérêt et possibilités de la spectrométrie de Fluorescence X (XRF)

peer reviewe

Conversion of green note aldehydes into alcohols by yeast alcohol dehydrogenase

‘Green note’ aldehydes were successfully reduced into their corresponding alcohol by commercial yeast alcohol dehydrogenase. Among different yeasts tested for their ability to convert (Z)-3-hexenal into (Z)-3-hexenol, Pichia anomala gave the best results. Conversion yields higher than 90% were also obtained by directly conducting the reaction in the medium where (Z)-3-hexenal is produced by the action of lipoxygenase and hydroperoxide lyase on linolenic acid

Revue bibliographique : l'hydroperoxyde lyase

Hydroperoxide lyase: a review. The hydroperoxide lyase belongs to the lipoxygenase pathway, pathway in which polyunsaturated fatty acids are transformed into a large spectrum of compounds with various chemical and biological functions. The hydroperoxide lyase acts on fatty acids hydroperoxides (mainly linoleic and linolenic). It cleaves the bond between carbon carrying the hydroperoxide function and a vicinal carbon giving an omega-oxo-acid and also depending on the species, an aldehyde, a hydrocarbon or an alcohol

Développement d'un système harmonisé de surveillance de la qualité des terres agricoles en Région wallonne anticipant la future directive européenne sur les sols

Setting-up of a soil monitoring system in Walloon Region anticipating the future European directive on soil. The European Commission currently finalizes its Framework Directive for soil protection waited for the end 2004. The project ARVA of the Walloon Region aims setting up the monitoring of arable land. The project proceeds in four phases: (i) the development of a soil monitoring which complies with the requirements of both the European regulation and the Walloon agriculture practices; (ii) the inventory of existing knowledge on the quality of soil in the Walloon Region and their relevance at Regional scale; (iii) the best estimate of the accuracy needed to detect evolutions in soil. To do this, test sites will help to validate the methodology used; (iv) an analysis of the strategies for structuring a future monitoring network. This strategy depends on the threat taken into consideration, as the selected options shall not compromise future needs for monitoring