Phenolic wastes valorization through bioenergy and bioactive compounds production

The agricultural and industrial processing activities produce large amounts of waste that are only partially valorised at different value-added levels (spread on land, animal feed, composting), whereas the main volumes are managed as waste of environmental worry. These by-products are rich sources of bioactive compounds, including phenolic compounds with high antioxidant activity

Energetic and biochemical valorization of cork boiling wastewater by anaerobic digestion

In addition to energy benefits, anaerobic digestion offers other interesting advantages. The cork industry is of great environmental, economic and social significance in the western Mediterranean region, with Portugal being the world-leading producer and exporter. Cork boiling wastewater (CBW) is a toxic and recalcitrant organic effluent produced by this sector, which constitutes a serious environmental hazard. However, there is no documented research on anaerobic treatment/valorization performed with this effluent. The work presented here was developed with the aim to use the anaerobic digestion process to convert the CBW polluting organic load into an energy carrier gas and valuable molecules for industry

Cork boiling wastewater anaerobic digestion process leads to biogas and valuable enzymes production

Cork is the outer bark of the cork-tree (Quercus suber L.) and it is a very important industrial sector in western Mediterranean region, being Portugal the world-leading producer and exporter (1). The anaerobic digestion has never been applied to the treatment and valorization of the industrial cork effluents (cork boiling wastewater, CBW). The goal of the present work is evaluate the role of this biological process in providing valuable biomolecules, i.e. enzymes, during the conversion of CBW. Anaerobic experiments were conducted under mesophilic conditions of temperature and the obtained results suggest that CBW is an interesting substrate to be treated and valorised through the anaerobic digestion. Besides the energy recovery through biogas production by anaerobic digestion of CBW, the increase in the reactor effluent of valuable biomolecules is an aspect of great industrial interest. The identification and characterization of such products of high added value creates a supplementary prospect of effluent valorisation, contributing to the cork sector profits. During the CBW anaerobic digestion process several important alterations on the enzymatic capacity of the digested flow were observed. For instance, the laccase activity contained in the CBW was implemented by anaerobiosis and the xilanase was formed during the process. Laccases exhibit low substrate specificity and can be used in different industrial sectors (i.e. paper manufacturing, wine stabilization and wastewater treatment) (2). Xylanases are enzymes involved in the hydrolyse carbohydrates and are used in the pulp, paper and food industries (3). The production of enzymes with commercial interest offers an additional opportunity for the biotechnological valorisation of the CBW, contributing to make the process more interesting and cheaper

Bioactive compounds through anaerobic digestion of heterotrophic microalgae residues

Several important biomolecules are available into anaerobically digested effluents that were obtained from the biodiesel production process using heterotrophically grown microalga Chlorella protothecoides. Defatted microalgae residues and crude glycerol may undergo anaerobic digestion, separately and in admixture, providing methane/hydrogen and a digestate exploitable for agriculture applications. Furthermore, industrial interesting bioactive compounds such as polyphenols provided with antioxidant activity can be obtained. Anaerobic process offers a promising chance and can be advantageously combined with algae lipid-extraction techniques in order to make it more sustainable

Null-exact controllability of a semilinear cascade system of parabolic-hyperbolic equations

This paper is concerned with the null-exact controllability of a cascade system formed by a semilinear heat and a semilinear wave equation in a cylinder Ω×(0, T). More precisely, we intend to drive the solution of the heat equation (resp. the wave equation) exactly to zero (resp. exactly to a prescribed but arbitrary final state). The control acts only on the heat equation and is supported by a set of the form ω × (0, T), where ω ⊂ Ω. In the wave equation, the restriction of the solution to the heat equation to another set O × (0, T) appears. The nonlinear terms are assumed to be globally Lipschitz-continuous. In the main result in this paper, we show that, under appropriate assumptions on T, ω and O, the equations are simultaneously controllable.Dirección General de Enseñanza SuperiorDirección General Asuntos del Personal Académico (Universidad Nacional Autónoma de México

Controllability of linear and semilinear non-diagonalizable parabolic systems

This paper is concerned with the controllability of some (linear and semilinear) nondiagonalizable parabolic systems of PDEs. We will show that the well known null controllability properties of the classical heat equation are also satisfied by these systems at least when there are as many scalar controls as equations and some (maybe technical) conditions are satisfied. We will also show that, in some particular situations, the number of controls can be reduced. The minimal amount is then determined by a Kalman rank condition.Ministerio de Ciencia e InnovaciónDirección General Asuntos del Personal Académico (Univeridad Nacional Autónoma de México

Boundary controllability of parabolic coupled equations

This paper is concerned with the boundary controllability of non-scalar linear parabolic systems. More precisely, two coupled one-dimensional parabolic equations are considered. We show that, in this framework, boundary controllability is not equivalent and is more complex than distributed controllability. In our main result, we provide necessary and sufficient conditions for the null controllability.Ministerio de Ciencia e InnovaciónDirección General Asuntos del Personal Académico (Univeridad Nacional Autónoma de México

Circuit model for mode conversion in coplanar waveguide asymmetric series-impedances

A new `circuit model' for converting between even and odd modes in asymmetric series impedances in the ground plane of a coplanar waveguide is presented. The model is based on the separation of modes into two input and two output ports. In contrast to previous work, it enables a quantitative analysis of the energy exchange between modes to be obtained.Peer Reviewe

Aglianico and Fiano wines obtained with an autochthonous non-Saccharomyces yeast

Non-Saccharomyces yeasts are microorganisms that play a prominent role in the fermentation dynamics, composition and flavour of wine. The principal aromatic compounds responsible for varietal aroma in wine are terpenes; of these, the monoterpenes represent the oenologically most important group in terms of volatility and odour, if they are present in a free form. The glycosidically bound forms can be converted into compounds with free odours by hydrolysis with the glycosidases produced by yeasts. We performed a screening of non-Saccharomyces yeasts present in the grapes and must of Aglianico and Fiano cultivars typical of South Italy (Irpinia), which have a high extra-cellular glycosidase activity. Among the species analysed was a strain belonging to Rhodotorula spp. that showed the highest glycosidase activity, an increased free terpene fraction and, simultaneously, little modification of the bouquet. The isolated yeast was subsequently utilized for experimental winemaking processes of Aglianico and Fiano wines. The results demonstrated that the obtained wines had a more intense floral aroma and some sweet and ripened fruit notes

Sur la contrôlabilité frontière des systèmes paraboliques non scalaires

This Note is concerned with the boundary controllability of non-scalar linear parabolic systems. More precisely, two coupled one-dimensional linear parabolic equations are considered. We show that, with boundary controls, the situation is much more complex than for similar distributed control systems. In our main result, we provide necessary and sufficient conditions for null controllability.Cette Note concerne la contrôlabilité frontière des systèmes paraboliques linéaires non scalaires. Plus précisement, on considère un système de deux équations paraboliques linéaires de dimension 1 en espace. Nous montrons qu'il est beaucoup plus compliqué de contrôler sur une partie du bord que de le faire avec des contrôles distribués. Dans notre résultat principal, on donne des conditions nécessaires et suffisantes pour la contrôlabilité exacte à zéro