Publications by authors named "Dubessay Pascal"

The olive oil industry generates 30 million cubic meters of olive mill wastewaters (OMWWs) annually. OMWWs are a major environmental concern in the Mediterranean region due to their high organic matter content, suspended solids, unpleasant odor, and dark color. The application of primary treatments such as coagulation-flocculation, adsorption, and hybrid systems combining coagulation-flocculation with adsorption has enabled to remove part of the organic matter, color, turbidity, and growth-inhibiting compounds from OMWWs.

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The ongoing discussion regarding the use of mixed or pure cultures of hydrogenotrophic methanogenic archaea in Power-to-Methane (P2M) bioprocess applications persists, with each option presenting its own advantages and disadvantages. To address this issue, a comparison of methane (CH) yield between a novel methanogenic archaeon belonging to the species Methanothermobacter marburgensis (strain Clermont) isolated from a biological methanation column, and the community from which it originated, was conducted. This comparison included the type strain M.

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Microalgae are capable of generating numerous metabolites that possess notable biological activities and hold substantial promise for various industrial applications. Nevertheless, the taxonomic diversity of these photosynthetic microorganisms has not received thorough investigation. Using the 18S rRNA encoding gene, a recently discovered strain originating from the Tunisian coast (the governorate of Mahdia) was identified as a member of the genus.

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Despite being one of the first enzymes discovered in 1883, the determination of laccase activity remains a scientific challenge, and a barrier to the full use of laccase as a biocatalyst. Indeed, laccase, an oxidase of the blue multi-copper oxidases family, has a wide range of substrates including substituted phenols, aromatic amines and lignin-related compounds. Its one-electron mechanism requires only oxygen and releases water as a reaction product.

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Marine algae are the most abundant resource in the marine environment and are still a promising source of bioactive compounds including hydrocolloids. This study contributes to the evaluation of the biological and biotechnological potentials of two water soluble polysaccharides, namely alginates (AHS) and fucoidan (FHS), extracted and purified from Halopteris scoparia, an abundant Tunisian brown macroalgae collected in Tunisia (Tabarka region). The total sugars, neutral monosaccharides, uronic acids, proteins, polyphenols, and sulfate groups contents were quantified for both fractions, as well as their functional groups and primary structural features by Fourier transform infrared spectroscopy, ionic and/or gas chromatography and nuclear magnetic resonance analyses.

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Cyanobacterial exopolysaccharides (EPS) are potential candidates for the production of sustainable biopolymers. Although the bioactive and physicochemical properties of cyanobacterial-based EPS are attractive, their commercial exploitation is limited by the high production costs. Bioprospecting and characterizing novel EPS-producing strains for industrially relevant conditions is key to facilitate their implementation in various biotechnological applications and fields.

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Taken separately, a single sweet sorghum stem bioconversion process for bioethanol and biomethane production only leads to a partial conversion of organic matter. The direct fermentation of crushed whole stem coupled with the methanization of the subsequent solid residues in a two-stage process was experimented to improve energy bioconversion yield, efficiency, and profitability. The raw stalk calorific value was 17,144.

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Article Synopsis
  • This study focuses on enhancing the properties of industrial lignin using an enzymatic process involving laccase from a specific type of fungus, tested under various pH levels and concentrations with a mediator.
  • The optimal conditions found were a pH of 4.5 over longer incubation times, which increased laccase activity against kraft lignin.
  • Multiple analytical techniques, including FTIR, DSC, and GC-MS, were used to analyze the structural changes and chemical modifications of lignin, confirming that laccase treatment can effectively modify marine pine kraft lignin.
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Alginates extracted from two Moroccan brown seaweeds and their derivatives were investigated for their ability to induce phenolic metabolism in the roots and leaves of tomato seedlings. Sodium alginates (ALSM and ALCM) were extracted from the brown seaweeds and , respectively. Low-molecular-weight alginates (OASM and OACM) were obtained after radical hydrolysis of the native alginates.

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Glucuronan is a polysaccharide composed of β-(1,4)-linked d-glucuronic acids having intrinsic properties and biological activities recoverable in many fields of application. Currently, the description of M5N1CS mutant bacterial strain as the sole source of glucuronan makes it relevant to the exploration of new microorganisms producing glucuronan. In this study, the strain (Rhizobia), was identified as a wild producer of an exopolysaccharide (RhrBR46) related to glucuronan.

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The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from   Medik. seeds, spontaneous shrub collected in Southern of Algerian Sahara were investigated. Their water extraction followed by alcoholic precipitation was conducted to obtain two water-soluble polysaccharides extracts (WSPAM1 and WSPAM2).

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In this present work, we developed a phenol grafted polyglucuronic acid (PGU) and investigated the usefulness in tissue engineering field by using this derivative as a bioink component allowing gelation in extrusion-based 3D bioprinting. The PGU derivative was obtained by conjugating with tyramine, and the aqueous solution of the derivative was curable through a horseradish peroxidase (HRP)-catalyzed reaction. From 2.

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Microsporidia are obligate intracellular pathogens capable of infecting a wide variety of hosts ranging from invertebrates to vertebrates. The infection process requires a step of prior adherence of Microsporidia to the surface of host cells. A few studies demonstrated the involvement of proteins containing a ricin-B lectin (RBL) domain in parasite infection.

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Polysaccharides extracted from marine algae have attracted much attention due to their biotechnological applications, including therapeutics, cosmetics, and mainly in agriculture and horticulture as biostimulants, biofertilizers, and stimulators of the natural defenses of plants. This study aimed to evaluate the ability of alginate isolated from from the Moroccan coast and oligoalginates derivatives to stimulate the natural defenses of tomato seedlings. Elicitation was carried out by the internodal injection of bioelicitor solutions.

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Bifunctional enzymes created by the fusion of a glucuronan lyase (TrGL) and a chitinase (ThCHIT42) from sp. have been constructed with the aim to validate a proof of concept regarding the potential of the chimera lyase/hydrolase by analyzing the functionality and the efficiency of the chimeric constructions compared to parental enzymes. All the chimeric enzymes, including or nor linker (GGGGS), were shown functional with activities equivalent or higher to native enzymes.

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is the main spoilage microbial agent in red wines. The use of fungal chitosan has been authorized since 2009 as a curative treatment to eliminate this yeast in conventional wines and in 2018 in organic wines. As this species is known to exhibit great genetic and phenotypic diversity, we examined whether all the strains responded the same way to chitosan treatment.

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Article Synopsis
  • * Neem seeds from Zidim produced higher quality oil and better biodiesel characteristics than those from Maroua, with average oil content of 56.75% versus 53.98%.
  • * Although the biodiesel produced has comparable qualities to petrodiesel, its relatively high free fatty acid content reduces yield (89.02%) and necessitates additional processing to enhance efficiency.
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Microalgae and their metabolites have been an El Dorado since the turn of the 21st century. Many scientific works and industrial exploitations have thus been set up. These developments have often highlighted the need to intensify the processes for biomass production in photo-autotrophy and exploit all the microalgae value including ExoPolySaccharides (EPS).

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Research on marine microalgae has been abundantly published and patented these last years leading to the production and/or the characterization of some biomolecules such as pigments, proteins, enzymes, biofuels, polyunsaturated fatty acids, enzymes and hydrocolloids. This literature focusing on metabolic pathways, structural characterization of biomolecules, taxonomy, optimization of culture conditions, biorefinery and downstream process is often optimistic considering the valorization of these biocompounds. However, the accumulation of knowledge associated with the development of processes and technologies for biomass production and its treatment has sometimes led to success in the commercial arena.

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The alpha-pinene oxide lyase (Prα-POL) from Pseudomonas rhodesiae CIP107491 belongs to catabolic alpha-pinene degradation pathway. In this study, the gene encoding Prα-POL has been identified using mapping approach combined to inverse PCR (iPCR) strategy. The Prα-POL gene included a 609-bp open reading frame encoding 202 amino acids and giving rise to a 23.

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The oxidation of natural polysaccharides by TEMPO has become by now an "old chemical reaction" which led to numerous studies mainly conducted on cellulose. This regioselective oxidation of primary alcohol groups of neutral polysaccharides has generated a new class of polyuronides not identified before in nature, even if the discovery of enzymes promoting an analogous oxidation has been more recently reported. Around the same time, the scientific community discovered the surprising biological and techno-functional properties of these anionic macromolecules with a high potential of application in numerous industrial fields.

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Article Synopsis
  • Poly-ADP ribosylation (PARylation) is a post-translational modification linked to DNA repair, with PARP-I being the main active form in Drosophila.
  • The study chemically induced strand-breaks in Drosophila S2 cells, observing minimal changes in PARylation during the damage and a slight increase in PARP mRNAs during recovery, which contrasts with human cells where PARylation is more active.
  • While PARP is crucial for maintaining DNA integrity in Drosophila, the findings suggest it is not essential for the actual repair of strand-breaks, indicating a tightly regulated PARylation process.
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DNA repair mechanisms are key components for the maintenance of the essential mitochondrial genome. Among them, base excision repair (BER) processes, dedicated in part to oxidative DNA damage, are individually well known in mitochondria. However, no large view of these systems in differential physiological conditions is available yet.

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The consequences of aging are characterized by a decline in the main cellular functions, including those of the mitochondria. Although these consequences have been much studied, efforts have often focused solely on a few parameters used to assess the "state" of mitochondrial function during aging. We performed comparative measurements of several parameters in young (a few days) and old (8 and 12 weeks) adult male Drosophila melanogaster: respiratory complex activities, mitochondrial respiration, ATP synthesis, lipid composition of the inner membrane, concentrations of respiratory complex subunits, expression of genes (nuclear and mitochondrial) coding for mitochondrial proteins.

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