Extraction et caractérisation biochimique des polyphénol oxydases de champignons et leur application en biocatalyse supportée

This work is devoted to the extraction of enzymes belonging to the polyphenol oxidase family from mushrooms, their biochemical characterization and their immobilization in solid hosts. These enzymes were first extracted from Paris mushrooms (Agaricus bisporus) and partially purified. A study of their enzymatic activity, stability conditions and thermal behavior was performed, together with the identification of inhibitors. A similar approach was applied to polyphenol oxidase extracted from desert truffle (Terfezia leonis Tul.). These enzymes were then trapped in silica gels for dopamine determination using an optical biosensor and in an alginate gel for phenol degradation.Ce travail concerne l'extraction d'enzymes de la famille des polyphénol oxydases à partir de champignons, leur caractérisation biochimique et leur immobilisation dans des matrices solides. Ces enzymes ont tout d'abord été extraites du champignon de Paris (Agaricus bisporus) puis partiellement purifiées. Une étude de leur activité enzymatique, de leur domaine de stabilité et de leur comportement thermique a été effectuée, ainsi que l'identification d'inhibiteurs. Cette approche a été étendue à la polyphénol oxydase de la truffe de désert (Terfezia leonis Tul.). Ces deux enzymes ont ensuite été piégées dans des gels de silice pour le dosage de la dopamine par un biocapteur optique et dans un gel d'alginate pour la dégradation du phénol

Extraction and biochemical caracterization of polyphenol oxidases from mushrooms and their application in biocatalysis

Ce travail concerne l'extraction d'enzymes de la famille des polyphénol oxydases à partir de champignons, leur caractérisation biochimique et leur immobilisation dans des matrices solides. Ces enzymes ont tout d'abord été extraites du champignon de Paris (Agaricus bisporus) puis partiellement purifiées. Une étude de leur activité enzymatique, de leur domaine de stabilité et de leur comportement thermique a été effectuée, ainsi que l'identification d'inhibiteurs. Cette approche a été étendue à la polyphénol oxydase de la truffe de désert (Terfezia leonis Tul.). Ces deux enzymes ont ensuite été piégées dans des gels de silice pour le dosage de la dopamine par un biocapteur optique et dans un gel d'alginate pour la dégradation du phénol.This work is devoted to the extraction of enzymes belonging to the polyphenol oxidase family from mushrooms, their biochemical characterization and their immobilization in solid hosts. These enzymes were first extracted from Paris mushrooms (Agaricus bisporus) and partially purified. A study of their enzymatic activity, stability conditions and thermal behavior was performed, together with the identification of inhibitors. A similar approach was applied to polyphenol oxidase extracted from desert truffle (Terfezia leonis Tul.). These enzymes were then trapped in silica gels for dopamine determination using an optical biosensor and in an alginate gel for phenol degradation

The Valorization of Biolignin from Esparto Grass <i>(</i><i>Stipa tenacissima</i> L.) Produced by Green Process CIMV (Compagnie Industrielle de la Matière Végétale) for Fertilization of Algerian Degraded Soil: Impact on the Physicochemical and Biological Properties

This study proposes a new use for a paper industry waste material, lignin, in agriculture and agronomy as a fertilizer for arid soils, while following a strategy aiming to both increase the amount of organic matter in these soils and decrease the impact of pollution caused by industrial discharges that contain organic and/or inorganic pollutants generated by the paper industry. In fact, this method works to improve soil quality through a new carbon-rich bioorganic fertilizer (biolignin) that results from a green method called CIMV, a targeted depollution objective of the paper industry. Over the course of 180 days, we monitored the physicochemical and biological characteristics of degraded soils treated with three different biolignin treatments of 0 (D0), 2 (D1), and 4 (D2) g/kg. The humification was then evaluated by the equation E4/E6. A remarkable variation of the physicochemical and biological parameters was observed in D1 and D2: temperature 12–38 °C, humidity 9–29%, and pH 7.06–8.73. The C/N ratio decreased from 266 to 49. After 180 days, the improvement in soil carbon content for the three treatments D0, D1, and D2 was 14%, 19%, and 24%, respectively. A maximum bacterial biomass of 152 (CFU/g soil) was observed on the 30th day for D1. Maximum laccase activity for D2 was observed on the 120th day. D1 and D2 recorded a significant degree of humification compared to D0. The best indicator of humification E4/E6 was observed in D1, where the value reached 2.66 at the end of the treatment period. The D2 treatment showed a remarkable effect improving the fertility of the degraded soil, which confirms that biolignin is a good fertilizer

An optical catechol biosensor based on a desert truffle tyrosinase extract immobilized into a sol–gel silica layered matrix

International audienceAn optical biosensor for the determination of catechol, a widely used yet toxic and carcinogenic molecule, is proposed using a crude extract of desert truffle (Terfezia leonis Tul.) as an enzymatic source of tyrosinase. The biosensor is constructed by the immobilization of tyrosinase crude extract in a bi-layered silica gel film prepared by dip-coating of an alkoxide/colloidal silica solution containing the enzyme on glass slide. Encapsulation has a moderate effect of the enzyme optimal pH stability but largely increases its thermal stability. Immobilized enzymes have a higher substrate affinity towards catechol but smaller maximum conversion velocity. The optical biosensor provides a linear response for catechol in the concentration range of 50–400 µM and a limit of detection was 52 µM. AFM studies show that the enzymes impact on the silica gel structure, preventing further deposition of additional layers. Comparison with similar dopamine biosensors points out that the impact of encapsulation on enzymatic activity may depend on the considered substrate