Valorization of edible plant by-products by fermentation for the production of added value compounds

Les enjeux de développement durable et de gestion des déchets sont de plus en plus considérés dans nos sociétés. Dans ce contexte, il est nécessaire de développer des recherches dans le but d’enrichir les connaissances scientifiques, et permettre de développer des systèmes de valorisation efficients. Parmi les voies de valorisation pour le recyclage des sous-produits végétaux, issus de l’industrie agroalimentaire, la fermentation peut être utilisée pour la production de métabolites à valeur ajoutée. Le projet dans le cadre duquel j’ai préparé ma thèse a été mené avec l’appui de cinq industriels du secteur agroalimentaire qui souhaitaient travailler sur la valorisation spécifique de leurs sous-produits végétaux : Charles et Alice, Florette, Panzani, Philibert Savours et Pierre Martinet. Les sous-produits associés sont respectivement des peaux de pommes, des épluchures de salades, du son de blé, du levain de germe de blé et de la pulpe de carottes. Dans un premier temps, des caractéristiques physico-chimiques (pH, teneur en eau, aw), biochimiques (acidité titrable, fractions azotées), et biologiques (flores microbiennes des produits bruts) de chacune de ces 5 matrices ont été déterminées. Couplé à des essais de fermentation spontanée, les résultats ont dans un premier temps permis de sélectionner une matrice de référence, la pulpe de carottes. La fermentation spontanée des sous-produits a été étudiée en faisant varier les paramètres d’incubation, selon un plan d’expérience factoriel, pour la matrice modèle. Les observations réalisées ont permis de sélectionner les conditions de fermentation des quatre autres sous-produits. Les mesures d’acidité (pH et acidité titrable) et le suivi de flores microbiennes au cours du temps ont montré la fermentescibilité des sous-produits. Pour la pulpe de carotte, les paramètres de culture choisis (broyage, température, pourcentage d’eau et rafraîchis) et les niveaux fixés, n’ont pas permis de favoriser la production de molécules d’intérêt parmi celles suivies : les composés phénoliques, les acides organiques et les composés volatils. En accord avec les partenaires du projet, la troisième partie avait pour objectif de sélectionner une souche de Lactobacillus, à partir de la matrice modèle, pour produire de l’acide L-lactique. La souche de Lactobacillus paracasei A1L sélectionnée a montré sa capacité à produire de l’acide L-lactique dans des quantités plus importantes qu’en fermentation spontanée, bien que celles-ci restent faibles pour envisager une application industrielle (quantité maximale produite = 0,974 g/L). Les essais réalisés selon un plan d’expérience D-optimal ont permis d’évaluer les effets de la température, du pH, de l’ajout d’enzymes (hémicellulase et protéase) et du taux d’ensemencement. Les résultats montrent que la production d’acide L-lactique est favorisée à une température de 25°C, un pH initial de 8 et une quantité de microorganismes ensemencée de 10E+8 UFC/mL. Au terme du projet, les connaissances acquises sur les dynamiques de fermentation, spontanée ou dirigée, sont des éléments qui permettront d’adapter les conditions de fermentationSustainable development and waste management issues are increasingly being considered in our societies. In this context, it is necessary to develop research to enrich scientific knowledge and enabling the development of efficient valorisation systems. Among the valorisation ways for the recycling of plant by-products from the food industry, fermentation can be used for the production of value-added compounds. My Ph D thesis project was carried out with the support of five food companies who wish to investigate specific valorisation routes for their by-products: Charles et Alice, Florette, Panzani, Philibert Savours and Pierre Martinet. The corresponding by-products are apple skins, salad peelings, wheat bran, wheat germ sourdough, and carrot pulp, respectively. First, matrix-specific physico-chemical (pH, water content, water activity (aW)), biochemical (nitrogen fractions, titratable acidity), and biological (microbial flora of the raw products) characteristics were determined. Coupled with spontaneous fermentation trials, the results enabled the selection of carrot pulp as a reference matrix, for further experiments. Incubation parameters of the spontaneous fermentation of carrot pulp were then varied according to a factorial experimental design. The results made it possible to select the fermentation conditions for the other four by-products. Acidity measurements (pH and titratable acidity) and monitoring of microbial flora over time showed the fermentability of by-products. For carrot pulp, the selected culture parameters (grinding of raw material, temperature, percentage of water and refreshments) and the levels set did not favour the production of molecules of interest among those monitored: phenolic compounds, organic acids, and volatile compounds. A screening allowed to isolate a L-lactic acid producing Lactobacillus strain from carrot pulp. The selected Lactobacillus paracasei A1L strain showed its ability to produce L-lactic acid in higher quantities than in spontaneous fermentation, however this concentration remains too low for an industrial application (maximum quantity produced = 0,974 g/L). Trials built according to a D-optimal experimental design tested the effect of temperature, pH, enzyme addition (hemicellulase and protease) and inoculum load. The results show that L-lactic acid production is favoured at a temperature of 25°C, an initial pH of 8, and a 10E+8 CFU/mL amount of microorganisms inoculated. The knowledge acquired on the dynamics of spontaneous fermentation or fermentation after inoculation, are elements that will allow to adapt the fermentation conditions in the futur

Valorisation de sous-produits végétaux par fermentation pour la production de composés à valeur ajoutée : Production d’acide L-lactique par fermentation de pulpe de carottes

Sustainable development and waste management issues are increasingly being considered in our societies. In this context, it is necessary to develop research to enrich scientific knowledge and enabling the development of efficient valorisation systems. Among the valorisation ways for the recycling of plant by-products from the food industry, fermentation can be used for the production of value-added compounds. My Ph D thesis project was carried out with the support of five food companies who wish to investigate specific valorisation routes for their by-products: Charles et Alice, Florette, Panzani, Philibert Savours and Pierre Martinet. The corresponding by-products are apple skins, salad peelings, wheat bran, wheat germ sourdough, and carrot pulp, respectively. First, matrix-specific physico-chemical (pH, water content, water activity (aW)), biochemical (nitrogen fractions, titratable acidity), and biological (microbial flora of the raw products) characteristics were determined. Coupled with spontaneous fermentation trials, the results enabled the selection of carrot pulp as a reference matrix, for further experiments. Incubation parameters of the spontaneous fermentation of carrot pulp were then varied according to a factorial experimental design. The results made it possible to select the fermentation conditions for the other four by-products. Acidity measurements (pH and titratable acidity) and monitoring of microbial flora over time showed the fermentability of by-products. For carrot pulp, the selected culture parameters (grinding of raw material, temperature, percentage of water and refreshments) and the levels set did not favour the production of molecules of interest among those monitored: phenolic compounds, organic acids, and volatile compounds. A screening allowed to isolate a L-lactic acid producing Lactobacillus strain from carrot pulp. The selected Lactobacillus paracasei A1L strain showed its ability to produce L-lactic acid in higher quantities than in spontaneous fermentation, however this concentration remains too low for an industrial application (maximum quantity produced = 0,974 g/L). Trials built according to a D-optimal experimental design tested the effect of temperature, pH, enzyme addition (hemicellulase and protease) and inoculum load. The results show that L-lactic acid production is favoured at a temperature of 25°C, an initial pH of 8, and a 10E+8 CFU/mL amount of microorganisms inoculated. The knowledge acquired on the dynamics of spontaneous fermentation or fermentation after inoculation, are elements that will allow to adapt the fermentation conditions in the futureLes enjeux de développement durable et de gestion des déchets sont de plus en plus considérés dans nos sociétés. Dans ce contexte, il est nécessaire de développer des recherches dans le but d’enrichir les connaissances scientifiques, et permettre de développer des systèmes de valorisation efficients. Parmi les voies de valorisation pour le recyclage des sous-produits végétaux, issus de l’industrie agroalimentaire, la fermentation peut être utilisée pour la production de métabolites à valeur ajoutée. Le projet dans le cadre duquel j’ai préparé ma thèse a été mené avec l’appui de cinq industriels du secteur agroalimentaire qui souhaitaient travailler sur la valorisation spécifique de leurs sous-produits végétaux : Charles et Alice, Florette, Panzani, Philibert Savours et Pierre Martinet. Les sous-produits associés sont respectivement des peaux de pommes, des épluchures de salades, du son de blé, du levain de germe de blé et de la pulpe de carottes. Dans un premier temps, des caractéristiques physico-chimiques (pH, teneur en eau, aw), biochimiques (acidité titrable, fractions azotées), et biologiques (flores microbiennes des produits bruts) de chacune de ces 5 matrices ont été déterminées. Couplé à des essais de fermentation spontanée, les résultats ont dans un premier temps permis de sélectionner une matrice de référence, la pulpe de carottes. La fermentation spontanée des sous-produits a été étudiée en faisant varier les paramètres d’incubation, selon un plan d’expérience factoriel, pour la matrice modèle. Les observations réalisées ont permis de sélectionner les conditions de fermentation des quatre autres sous-produits. Les mesures d’acidité (pH et acidité titrable) et le suivi de flores microbiennes au cours du temps ont montré la fermentescibilité des sous-produits. Pour la pulpe de carotte, les paramètres de culture choisis (broyage, température, pourcentage d’eau et rafraîchis) et les niveaux fixés, n’ont pas permis de favoriser la production de molécules d’intérêt parmi celles suivies : les composés phénoliques, les acides organiques et les composés volatils. En accord avec les partenaires du projet, la troisième partie avait pour objectif de sélectionner une souche de Lactobacillus, à partir de la matrice modèle, pour produire de l’acide L-lactique. La souche de Lactobacillus paracasei A1L sélectionnée a montré sa capacité à produire de l’acide L-lactique dans des quantités plus importantes qu’en fermentation spontanée, bien que celles-ci restent faibles pour envisager une application industrielle (quantité maximale produite = 0,974 g/L). Les essais réalisés selon un plan d’expérience D-optimal ont permis d’évaluer les effets de la température, du pH, de l’ajout d’enzymes (hémicellulase et protéase) et du taux d’ensemencement. Les résultats montrent que la production d’acide L-lactique est favorisée à une température de 25°C, un pH initial de 8 et une quantité de microorganismes ensemencée de 10E+8 UFC/mL. Au terme du projet, les connaissances acquises sur les dynamiques de fermentation, spontanée ou dirigée, sont des éléments qui permettront d’adapter les conditions de fermentatio

Evolution of carrot pulps during spontaneous fermentation

International audienceThe spontaneous fermentation of carrot pulps was followed under different conditions during nine consecutive days. Trials were carried out to obtain interesting compounds: organic acids and volatile molecules. Factors were tested with a two-level full factorial design: temperature (24°C/37°C), grinding (with/without), addition of water (0%/50% w/w) and refreshment of the fermentation medium (without/after 3 or 7 days of incubation). During the course of the fermentations, different parameters were measured: microbial gross composition and diversity (REP-PCR), pH, lactic and acetic acids, ethanol, phenolic and volatiles compounds (SPME-GC-MS). Whatever the culture conditions tested, the pulp ecosystem remained quantitatively stable from the beginning to the end of the culture step. It was dominated by lactic acid bacteria (LAB), followed by Enterococci, yeasts, moulds and acetic acid bacteria (AAB); Enterobacteriaceae, Bacillus and Pseudomonas were found at low levels. However, the composition of each population changed. As a consequence, the LAB proved to be the most influencing population on the production of ethanol, acetic acid and lactic acid. 2-Butanol was also detected in the fermented pulps; but no relation was found with the microorganisms looked for. Among the factors tested, the rise in temperature led to a decrease in the production of acetic acid, ethanol and D-lactic acid

Evolution of carrot pulps during spontaneous fermentation

International audienceThe spontaneous fermentation of carrot pulps was followed under different conditions during nine consecutive days. Trials were carried out to obtain interesting compounds: organic acids and volatile molecules. Factors were tested with a two-level full factorial design: temperature (24°C/37°C), grinding (with/without), addition of water (0%/50% w/w) and refreshment of the fermentation medium (without/after 3 or 7 days of incubation). During the course of the fermentations, different parameters were measured: microbial gross composition and diversity (REP-PCR), pH, lactic and acetic acids, ethanol, phenolic and volatiles compounds (SPME-GC-MS). Whatever the culture conditions tested, the pulp ecosystem remained quantitatively stable from the beginning to the end of the culture step. It was dominated by lactic acid bacteria (LAB), followed by Enterococci, yeasts, moulds and acetic acid bacteria (AAB); Enterobacteriaceae, Bacillus and Pseudomonas were found at low levels. However, the composition of each population changed. As a consequence, the LAB proved to be the most influencing population on the production of ethanol, acetic acid and lactic acid. 2-Butanol was also detected in the fermented pulps; but no relation was found with the microorganisms looked for. Among the factors tested, the rise in temperature led to a decrease in the production of acetic acid, ethanol and D-lactic acid

Characterization of milkisin, a novel lipopeptide with antimicrobial properties produced by Pseudomonas sp. UCMA 17988

International audienc

Past, Present, and Future of Non-invasive Brain Stimulation Approaches to Treat Cognitive Impairment in Neurodegenerative Diseases: Time for a Comprehensive Critical Review

International audienceLow birth rates and increasing life expectancy experienced by developed societies have placed an unprecedented pressure on governments and the health system to deal effectively with the human, social and financial burden associated to aging-related diseases. At present, ∼24 million people worldwide suffer from cognitive neurodegenerative diseases, a prevalence that doubles every five years. Pharmacological therapies and cognitive training/rehabilitation have generated temporary hope and, occasionally, proof of mild relief. Nonetheless, these approaches are yet to demonstrate a meaningful therapeutic impact and changes in prognosis. We here review evidence gathered for nearly a decade on non-invasive brain stimulation (NIBS), a less known therapeutic strategy aiming to limit cognitive decline associated with neurodegenerative conditions. Transcranial Magnetic Stimulation and Transcranial Direct Current Stimulation, two of the most popular NIBS technologies, use electrical fields generated non-invasively in the brain to long-lastingly enhance the excitability/activity of key brain regions contributing to relevant cognitive processes. The current comprehensive critical review presents proof-of-concept evidence and meaningful cognitive outcomes of NIBS in eight of the most prevalent neurodegenerative pathologies affecting cognition: Alzheimer’s Disease, Parkinson’s Disease, Dementia with Lewy Bodies, Primary Progressive Aphasias (PPA), behavioral variant of Frontotemporal Dementia, Corticobasal Syndrome, Progressive Supranuclear Palsy, and Posterior Cortical Atrophy. We analyzed a total of 70 internationally published studies: 33 focusing on Alzheimer’s disease, 19 on PPA and 18 on the remaining neurodegenerative pathologies. The therapeutic benefit and clinical significance of NIBS remains inconclusive, in particular given the lack of a sufficient number of double-blind placebo-controlled randomized clinical trials using multiday stimulation regimes, the heterogeneity of the protocols, and adequate behavioral and neuroimaging response biomarkers, able to show lasting effects and an impact on prognosis. The field remains promising but, to make further progress, research efforts need to take in account the latest evidence of the anatomical and neurophysiological features underlying cognitive deficits in these patient populations. Moreover, as the development of in vivo biomarkers are ongoing, allowing for an early diagnosis of these neuro-cognitive conditions, one could consider a scenario in which NIBS treatment will be personalized and made part of a cognitive rehabilitation program, or useful as a potential adjunct to drug therapies since the earliest stages of suh diseases. Research should also integrate novel knowledge on the mechanisms and constraints guiding the impact of electrical and magnetic fields on cerebral tissues and brain activity, and incorporate the principles of information-based neurostimulation

Antimicrobial potential of cyclic lipopeptide Milkisin, a new member of amphisin family

International audienc

Characterization of Milkisin, a Novel Lipopeptide With Antimicrobial Properties Produced By Pseudomonas sp. UCMA 17988 Isolated From Bovine Raw Milk

Biosurfactants such as lipopeptides are amphiphilic compounds produced by microorganisms such as bacteria of the genera of Pseudomonas and Bacillus. Some of these molecules proved to have interesting antimicrobial, antiviral, insecticide, and/or tensioactive properties that are potentially useful for the agricultural, chemical, food, and pharmaceutical industries. Raw milk provides a physicochemical environment that is favorable to the multiplication of a broad spectrum of microorganisms. Among them, psychrotrophic bacterial species, especially members of the genus Pseudomonas, are predominant and colonize milk during cold storage and/or processing. We isolated the strain Pseudomonas sp. UCMA 17988 from raw cow milk, with antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica Newport. Antimicrobial molecules involved in the antagonistic activity of this strain were characterized. A mass spectrometry analysis highlighted the presence of four lipopeptides isoforms. The major isoform (1409 m/z), composed of 10 carbons in the lipidic chain, was named milkisin C. The three other isoforms detected at 1381, 1395, and 1423 m/z, that are concomitantly produced, were named milkisin A, B, and D, respectively. The structure of milkisin, as confirmed by nuclear magnetic resonance analyses, is closely related to amphisin family. Indeed, the peptidic chain was composed of 11 amino acids, 6 of which are conserved among the family. In conclusion, Pseudomonas sp. UCMA 17988 produces new members of the amphisin family which are responsible for the antagonistic activity of this strain

Table_1_Characterization of Milkisin, a Novel Lipopeptide With Antimicrobial Properties Produced By Pseudomonas sp. UCMA 17988 Isolated From Bovine Raw Milk.docx

<p>Biosurfactants such as lipopeptides are amphiphilic compounds produced by microorganisms such as bacteria of the genera of Pseudomonas and Bacillus. Some of these molecules proved to have interesting antimicrobial, antiviral, insecticide, and/or tensioactive properties that are potentially useful for the agricultural, chemical, food, and pharmaceutical industries. Raw milk provides a physicochemical environment that is favorable to the multiplication of a broad spectrum of microorganisms. Among them, psychrotrophic bacterial species, especially members of the genus Pseudomonas, are predominant and colonize milk during cold storage and/or processing. We isolated the strain Pseudomonas sp. UCMA 17988 from raw cow milk, with antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica Newport. Antimicrobial molecules involved in the antagonistic activity of this strain were characterized. A mass spectrometry analysis highlighted the presence of four lipopeptides isoforms. The major isoform (1409 m/z), composed of 10 carbons in the lipidic chain, was named milkisin C. The three other isoforms detected at 1381, 1395, and 1423 m/z, that are concomitantly produced, were named milkisin A, B, and D, respectively. The structure of milkisin, as confirmed by nuclear magnetic resonance analyses, is closely related to amphisin family. Indeed, the peptidic chain was composed of 11 amino acids, 6 of which are conserved among the family. In conclusion, Pseudomonas sp. UCMA 17988 produces new members of the amphisin family which are responsible for the antagonistic activity of this strain.</p

Presentation_1_Characterization of Milkisin, a Novel Lipopeptide With Antimicrobial Properties Produced By Pseudomonas sp. UCMA 17988 Isolated From Bovine Raw Milk.pdf

<p>Biosurfactants such as lipopeptides are amphiphilic compounds produced by microorganisms such as bacteria of the genera of Pseudomonas and Bacillus. Some of these molecules proved to have interesting antimicrobial, antiviral, insecticide, and/or tensioactive properties that are potentially useful for the agricultural, chemical, food, and pharmaceutical industries. Raw milk provides a physicochemical environment that is favorable to the multiplication of a broad spectrum of microorganisms. Among them, psychrotrophic bacterial species, especially members of the genus Pseudomonas, are predominant and colonize milk during cold storage and/or processing. We isolated the strain Pseudomonas sp. UCMA 17988 from raw cow milk, with antagonistic activity against Listeria monocytogenes, Staphylococcus aureus, and Salmonella enterica Newport. Antimicrobial molecules involved in the antagonistic activity of this strain were characterized. A mass spectrometry analysis highlighted the presence of four lipopeptides isoforms. The major isoform (1409 m/z), composed of 10 carbons in the lipidic chain, was named milkisin C. The three other isoforms detected at 1381, 1395, and 1423 m/z, that are concomitantly produced, were named milkisin A, B, and D, respectively. The structure of milkisin, as confirmed by nuclear magnetic resonance analyses, is closely related to amphisin family. Indeed, the peptidic chain was composed of 11 amino acids, 6 of which are conserved among the family. In conclusion, Pseudomonas sp. UCMA 17988 produces new members of the amphisin family which are responsible for the antagonistic activity of this strain.</p