Philippe Michaud

Université Clermont Auvergne | Univ BPC · Clermont Auvergne INP - Institut Pascal

Exopolysaccharides (EPS) from the microalgae Porphyridium cruentum, Chrysotila dentata, Pavlova sp., Diacronema sp., Glossomastix sp., Phaeodactylum tricornutum, and Synechococcus sp. were isolated and depolymerized. First, EPS were submitted to a high pressure pre-treatment step, followed by a solid acid-catalyzed hydrolysis step carried out in a...

Biologically active compounds, including polysaccharides isolated from microalgae, have various properties. Although Nannochloropsis spp. have the potential to produce secondary metabolites important for biotechnology, only a small part of the research on these microalgae has focused on their ability to produce polysaccharide fractions. This study...

Chitosan is a polysaccharide resulting from chitin deacetylation. It has demonstrated interesting characteristics in the field of adhesion but loses most of its adhesive resistance in moist environment. A chemical crosslinking of chitosan with genipin has been implemented to improve its adhesive properties in the presence of water. The study of cr...

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...

The urgent need to tackle the significant public health challenge of diabetes mellitus requires a prompt focus on the exploration of novel and effective antidiabetic medications with limited side effects. The primary objective of this study was to examine the influence of the partial acid hydrolysis of a polysaccharide derived from Plantago ciliata...

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 ind...

Phycobiliproteins are photosynthetic light-harvesting pigments isolated from microalgae with fluorescent, colorimetric and biological properties, making them a potential commodity in the pharmaceutical, cosmetic and food industries. Hence, improving their metabolic yield is of great interest. In this regard, the present review aimed, first, to prov...

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...

This study explored the impact of date palm seeds ethanolic extract (DSEE) on the microbiological, physicochemical, and sensory qualities of chicken breast meat kept refrigerated at 4 °C. DSEE was applied at 0.156% (DSEE1), 0.312% (DSEE2), and 0.624% (DSEE4). Microbiological parameters, chemical stability, and sensory features of DSEE were monitore...

Mild cognitive impairment (MCI) is characterized by an abnormal decline in mental and cognitive function compared with normal cognitive aging. It is an underlying condition of Alzheimer's disease (AD), an irreversible neurodegenerative disease. In recent years, neuroinflam-mation has been investigated as a new leading target that contributes to MCI...

Here, we report work on developing an enzymatic process to improve the functionalities of industrial lignin. A kraft lignin sample prepared from marine pine was treated with the high-redox-potential laccase from the basidiomycete fungus Pycnoporus cinnabarinus at three different concentrations and pH conditions, and with and without the chemical me...

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 Sargassum muticum and Cystoseira myriophylloides, respectively. Low-molecular-weight alginat...

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 Sinorhyzobium meliloti M5N1CS mutant bacterial strain as the sole source of glucuronan makes it relevant to the exploration of new microorganisms...

Ultrasound pretreatment and microwave-assisted extraction (MAE) techniques were used to extract pectin from watermelon rind. This work investigated the effect of the power and time of pretreatment on the yield and characteristics of the extracted pectin. Imaging studies showed that ultrasonic pretreatment changed the morphology of the raw powder, l...

According to the FAO and WHO, half of the world’s population (nearly eight billion people) is protein deficient. Protein deficiency is the most important nutritional problem in the world. Proteins can be animal- (meat and offal, fish, milk, eggs) or plant- (cereals, legumes, oilseeds) based, microbiologically synthesized (from yeast and a variety o...

Algae constitute a significant part of marine biodiversity. They represent a renewable source of bioactive metabolites from drug development and therapeutic fields. Fucoxanthin and β-carotene from the brown macroalgae Halopteris scoparia, were extracted using conventional organic solvent extraction, then purified, to homogeneity, based on various c...

Extrusion and hot compressing molding processes were used to create bio-polyethylene (BioPE) composites reinforced with argan byproducts (shell, pulp, and argan cake) as bio-fillers. The thermal stability of the composites wass analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Dynamical mechanical analysis an...

Thanks to their various promising properties, bioactive peptides extracted from microalgae have recently attracted great attention from scientists. These compounds have been mostly obtained by enzymatic hydrolysis. In the present study, proteins from the marine microalga Rhodomonas sp. were hydrolysated into peptides using alcalase and pepsin. Afte...

The objective of the current work is to extract a new mucilage fraction from Astragalus gyzensis Bunge. seeds, which are collected from the El-Oued province (septentrional Algerian Sahara) and evaluated for their antidiabetic potential. The mucilage fraction is obtained using hot water extraction followed by alcoholic precipitation of polysaccharid...

Due to growing health concerns, the urban population is utterly inclined towards a healthy lifestyle and incorporated nutritional food supplements to lower common health risks. The ω-3 and ω-6 PUFAs consumption is increasing, hence alternative commercial production is essentially developed. The microbial source is an emerging platform to overcome t...

Parachlamydia acanthamoebae and Simkania negevensis, two Chlamydia-like bacteria, have been recently recognized as emerging human respiratory pathogens. The prevalence and frequency of these bacteria in the environment and among atypical pneumonia patients are still underestimated by classical culture, immunohistochemistry and serology which are no...

Sweet sorghum stalks energy recovery is one of the most interesting alternatives to meet the current challenge of energy security. The usual ethanol production process from this biomass proves to be less profitable due to very expensive juice extraction step. This study aims to improve the performance and efficiency of this process experimenting ne...

Unlike photoautotrophy, heterotrophy is a mode in which the absence of light, organic carbon dissolved in the culture media are used as substrates for energy production and growth in aerobic using respiration. Mixotrophy is another process of a culture where microalgae combine the two modes (photoautotrophy and heterotrophy). Indeed, during mixotro...

Microalgae are widely used to produce sorbitol, ethyl and methyl alcohols, acetone, organic acids, esters, pigments, chlorophylls, carotenoids, and other compounds. The purpose of this work was to study the potential of the Baltic Sea microalgae Arthrospira platensis and Chlorella vulgaris, as new ingredients for functional bread. Bread was baked w...

Lignins are by-products from biorefinery and paper industries. Their chemical structures are complex, and they are currently mainly used for energy and heat production generated by their combustion. In a context of higher value applications of lignins, lignin-based composites with lignosulfonate matrix and wood fibers reinforcement were pre-treated...

Sorghum (Sorghum bicolor L. Moench) is a flowering plant in the grass family (Poaceae) characterized by a great genotypic and phenotypic diversity, making it a cereal species of major interest cultivated in warm climate worldwide. Fifth most cultivated cereal in the world and second in Africa, sorghum is the main cultivated species in the Sahelian...

Argan nut shell represents the most generated by-product during the process of the extraction of argan oil. For the first time, argan nut shell was characterized and assessed as a new potential feedstock for bioethanol production using a combination of mechanical and enzymatic pretreatment. Argan shell samples were first disintegrated using the Sta...

Clematis flammula is widely used for its pharmacological properties in Tunisia. This work aimed to explore, in a rat model, the cardiopreventive capacity of polysaccharides extracted from C. flammula (CFPS) after a myocardial injury caused by isoproterenol. Structural analyses suggested that the average molecular weight of CFPS was 1.82 × 105 g/mol...

Human respiratory infections caused by a large variety of microbial pathogens are the most common diseases responsible for hospitalization, morbidity and mortality. Parachlamydia acanthamoebae, a Chlamydia-related bacterium, has been found to be potentially associated with these diseases. An early and accurate diagnosis of this pathogen could be us...

The Baltic Sea algae species composition includes marine euryhaline, freshwater euryhaline, and true brackish water forms. This study aimed to isolate a lipid–pigment complex from microalgae of the Baltic Sea (Kaliningrad region) and investigate its antimicrobial activity against Gram-positive and Gram-negative bacteria. Microalgae were sampled usi...

Healthy foods containing omega-3/omega-6 polyunsaturated fatty acids (PUFAs) have been in great demand because of their unique dietary and health properties. Reduction in chronic inflammatory and autoimmune diseases has shown their therapeutic and health-promoting effects when consumed under recommended ratio 1:1-1:4, however imbalanced ratios (>1:...

Due to the increase in industrial demand for new biosourced molecules (notably bioactive exopolysaccharides (EPS)), microalgae are gaining popularity because of their potential nutraceutical and health benefits. Such health effects are delivered by specific secondary metabolites, e.g., pigments, exopolysaccharides, polyunsaturated fatty acids, prot...

Microalgae are rich in proteins, carbohydrates, lipids, polyunsaturated fatty acids, vitamins, pigments, enzymes, and other biologically active substances. This research aimed to study the composition and antioxidant and antimicrobial activity of proteins, lipids, and carbohydrates of microalgae found in the Filinskaya Bay of the Kaliningrad region...

A novel sulfated xylogalactan (JASX) was extracted and purified from the rhodophyceae Jania adhaerens. JASX was characterized by chromatography (GC/MS-EI and SEC/MALLS) and spectroscopy (ATR-FTIR and 1H/13C NMR) techniques. Results showed that JASX was constituted by repeating units of (→3)-β-d-Galp-(1,4)-3,6-α-l-AnGalp-(1→)n and (→3)-β-d-Galp-(1,4...

Phycoremediation of heavy metals from contaminated waters by oleaginous microalgae is an eco-friendly and emerging trend. Different concentrations of toxic metals such as nickel (Ni), chromium (Cr) and cobalt (Co) were added in Tetraselmis sp. culture media. Mixture Design was used to model the effect of these metals on cell growth, lipid productio...

Microalgae are photoautotrophic microorganisms known as producers of a large variety of metabolites. The taxonomic diversity of these microorganisms has been poorly explored. In this study, a newly isolated strain was identified based on the 18S rRNA encoding gene. The phylogenetic analysis showed that the isolated strain was affiliated with the Rh...

The brown Tunisian seaweed Halopteris scoparia was used as a feedstock for producing renewable bioethanol, biogas, and biodiesel to demonstrate the proof of concept for the North African energy sector. A quantitative and qualitative quantification of H. scoparia composition using different colorimetric methods was completed to highlight its bioconv...

Lignocellulose, the main component of plant cell walls, comprises polyaromatic lignin and fermentable materials, cellulose and hemicellulose. It is a plentiful and renewable feedstock for chemicals and energy. It can serve as a raw material for the production of various value-added products, including cellulase and xylanase. Cellulase is essential...

Methods for purifying, detecting, and characterizing protein concentrate, carbohydrates, lipids, and neutral fats from the microalgae were developed as a result of research. Microalgae were collected from natural sources (water, sand, soil of the Kaliningrad region, Russia). Microalgae were identified based on morphology and polymerase chain reacti...

Given the increasing interest that is being paid to polysaccharides derived from algae as plant natural defense stimulators, the degree of sulfation of exopolysaccharides produced by P. sordidum for inducing defense responses in date palm vitroplants was investigated. Firstly, the culture parameters of P. sordidum were optimized to maximize the amo...

Alginate is a hydrocolloid from algae, specifically brown algae, which is a group that includes many of the seaweeds, like kelps and an extracellular polymer of some bacteria. Sodium alginate is one of the best-known members of the hydrogel group. The hydrogel is a water-swollen and cross-linked polymeric network produced by the simple reaction of...

The development of eco-friendly cosmetic such as those from microalgae for skin regeneration and collagen synthesis has gained a great interest worldwide. Accordingly, the potential of microalgae biomass as source of anti-aging cosmetic cream with high antioxidant activity has been investigated. Stabilities and sensory characteristics of cosmetic c...

Sulfated glycoproteins extracted for the first time from the Moroccan green seaweed Codium decorticatum were investigated for their ability to induce a natural defense metabolism in the roots and the upper leaves of tomato seedlings. The crude (AGB) and the purified fractions (AGP) were characterized chemically (Colorimetric assays) and structurall...

The coronavirus pandemic (COVID-19) has created an urgent need to develop effective strategies for prevention and treatment. In this context, therapies against protease Mpro, a conserved viral target, would be essential to contain the spread of the virus and reduce mortality. Using combined techniques of structure modelling, in silico docking and p...

The influence of soaking and germination on the physicochemical characteristics of tigernut tubers (Cyperus esculentus L.) are investigated. Tubers (Ø > 1 cm) were soaked in an ascorbic acid solution (0.1%) for 48 h at 40 °C before undergoing germination for 6 days. The textural profile, the capacity and germination energy and the biochemical compo...

The beneficial properties of algae make them perfect functional ingredients for food products. Algae have a high energy value and are a source of biologically active substances, proteins, fats, carbohydrates, vitamins, and macro- and microelements. They are also rich in polyunsaturated fatty acids, proteins, mycosporine-like amino acids, polysaccha...

Lignocellulosic by-products are frequently disposed by means of combustion. This study investigates an alternative route for corn cob and Kraft lignin resources in order to support circular economy. The respective plant-based fibres and filler were compounded for the first time together with a poly(lactic acid) (PLA) matrix. Consecutively, seven di...

Glucuronan and succinoglycan are two anionic exopoysaccharides produced by some soil bacteria and abundantly published by the community working on high valuable hydrocolloids. The glucuronan is a linear homopolymer of β-(1,4)-D�glucuronic acids sometimes subsituted by O-acetyl, whereas succinoglycan is ramified heteropolymer of β-(1,6) and β-(1,4)...

In the current context of the COVID-19 pandemic, it appears that our scientific resources and the medical community are not sufficiently developed to combat rapid viral spread all over the world. A number of viruses causing epidemics have already disseminated across the world in the last few years, such as the dengue or chinkungunya virus, the Ebol...

Nowadays, microalgae and cyanobacteria have become a promising and sustainable source of useful products, thanks to their richness in bioactive metabolites of high value (antibiotics, toxins, pharmaceutically active compounds, plant growth regulators, and others). These photoautotroph microorganisms generate biomass using photosynthesis. This revie...

Recent years, algal polysaccharides were mainly investigated for pharmaceutical, nutraceuticals and biomedical applications due to their promising bioactive properties. Moreover, it is now becoming a potential source for several non-medical and non-food applications in which biofuels are a major sector. The marine algae contain a variety of polysac...

The COVID-19 new variants spread rapidly all over the world, and until now scientists strive to find virus-specific antivirals for its treatment. The main protease of SARS-CoV-2 (Mpro) exhibits high structural and sequence homology to main protease of SARS-CoV (93.23% sequence identity), and their sequence alignment indicated 12 mutated/variant res...

In many African countries, the Bayoud is a common disease spread involving the fungus Fusarium oxusporum f. sp. albedinis (Foa). The induction of plant natural defenses through the use of seaweed polysaccharides to help plants against pathogens is currently a biological and ecological approach that is gaining more and more importance. In the presen...

Three-dimensional (3D) printing or additive manufacturing is a technology that has drastically developed in recent years for numerous industrial applications. Among the 3D printing methods, fused deposition modeling requires filaments to generate 3D objects. Currently, the polymers used in this technology are synthetic ones derived from nonrenewabl...

As a general rule, in a sustainable food model for the future of the growing world population, food biotechnology could be considered as a reliable for improving and increasing food production and processing. Food biotechnology consist of (1) genetic engineering approach (on plants, animals, or microorganisms) to improve food quality, (2) commercia...

The anti-inflammatory and antihyperglycemic effects of polysaccharides extracted from Alhagi maurorum 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). They were...

Alhagi maurorum Medik. (Fabaceae) is a spontaneous shrub native to the region extending from Russia to the Mediterranean and used by rural and Saharan Algerian people for its medicinal effects. This study aims to document the medicinal uses of A. maurorum in Illizi (southern Algeria). Ethnobotanical survey was carried out in Illizi between June and...

Polysaccharides are complex macromolecules long regarded as energetic storage resources or as components of plant and fungal cell walls. They have also been described as plant mucilages or microbial exopolysaccharides. The development of glycosciences has led to a partial and difficult deciphering of their other biological functions in living organ...