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Active microbes likely have larger impact on gut health status compared to inactive or dormant microbes. We investigate the composition of active and total mucosal microbiota of treatment-naïve ulcerative colitis (UC) patients to determine the microbial picture at the start-up phase of disease, using both a 16S rRNA transcript and gene amplicon sequencing. DNA and RNA were isolated from the same mucosal colonic biopsies. Our aim was to identify active microbial members of the microbiota in early stages of disease and reveal which members are present, but do not act as major players. We demonstrated differences in active and total microbiota of UC patients when comparing inflamed to non-inflamed tissue. Several taxa, among them the Proteobacteria phyla and families therein, revealed lower transcriptional activity despite a high presence. The Bifidobacteriaceae family of the Actinobacteria phylum showed lower abundance in the active microbiota, although no difference in presence was detected. The most abundant microbiota members of the inflamed tissue in UC patients were not the most active. Knowledge of active members of microbiota in UC patients could enhance our understanding of disease etiology. The active microbial community composition did not deviate from the total when comparing UC patients to non-IBD controls.

INTRODUCTION AND OBJECTIVES While functional foods have prompted growing interest to enhance the daily intakes of specific nutrients and to prevent deficiencies , their processes and storage can affect stability, solubility and bioavailability. To overcome these limitations, one alternative is the encapsulation of agents acting into carriers. To ensure industrial sustainability, such encapsulating material should be natural food-grade components (biocarriers), using economical and reliable raw materials and processes. The complex coacervation consists in mixing two polymers of opposite charges. Coacervation exploits the balance of electrostatic interactions between the two biopolymers to form a supramolecular assembly. Coacervation may display high shell integrity and encapsulation efficiency, good controlledrelease properties and mild preparation conditions. These features are interesting to reduce the industrial processing costs (Yan & Zhang, 2014). Whey proteins (WP) is by- products of the dairy industry, providing intrinsic biological properties. Two specific whey proteins has been selected β-lactoglobulin (BLG) and Lactoferrin (LF) as they able to co-assemble by complex coacervation. Recently the proof of concept that LF-BLG complex coacervates efficiently entrap vitamin B9 (B9) has been established at laboratory scale (Chapeau et al., 2016). This work focuses on the scale-up production of B9-WP coacervates for potential industrial applications. Coacervation is known to be highly sensitive to processing i.e. working volume, interfaces, and mixing conditions. Empirical scale-up could therefore result in increased costs, resources and efforts (Lemetter et al., 2004). Moreover, B9-WP coacervates should preserve the bioavailability of B9 during oral delivery. As a result, this study aims at: 1) investigating the scale-up production of B9-WP coacervate by comparing two mixing systems (in batch or in continuous), and 2) exploring the bioavailability of orally administered B9-WP coacervates.

Control of molecular assemblies provides possibility of constructing functional materials in a non-covalent bottom-up manner. Adequate mixing of oppositely charged proteins leads to liquid-liquid phase separation with the formation of reversible heteroprotein complex coacervates having great potential for application as functional biomaterials. For instance, the use of complex coacervates as carrier for nutraceuticals and bioactive components is a blooming research field. Here, we investigated the ability of complex coacervates formed between two whey proteins, Beta-lactoglobulin (BLG) and Lactoferrin (LF), to encapsulate an essential vitamin, the vitamin B9.Across a range of B9:Protein ratios, complex coacervation conditions were determined using turbidity and phase contrast microscopy. Biocarrier efficiency of protein coacervates for B9 was quantified. Stability of B9-Proteins coacervates was monitored after storage at 4°C and 20 °C, and freeze drying. Increasing volumes of B9-Proteins coacervates solutions were tested to evaluate the impact of process conditions on the coacervation yield.By plotting screening maps of B9:Protein ratios and B9 carrying efficiencies (Fig. 1A), we found an optimal biocarrier efficiency of ≈ 10 mg B9/g Proteins. This efficiency found for protein coacervates (Fig. 1B) is similar to that reported for other encapsulation technology like spray-drying [1]. B9-Proteins coacervates after centrifugation (Fig. 1C) were stable over a month storage at 4°C and 20°C, and after freeze drying, without any detectable degradation of B9. Working volumes showed an important impact of the homogenization and centrifugation conditions on the recovered coacervated phase.These heteroprotein systems display useful potentialities as carrying biomaterial [2]. Their formation requires minimal energy input and involves co-products of the dairy industry. Few mg of coacervates can cover the recommended daily intake of bioactives and enhance protein intake. They constitute new potential structured biopolymer-based delivery system. They use directly components of the food product as carrying biomaterial, thus limiting the addition of extraneous components to develop natural functional foods or ingredients.

The mechanism of interaction of two oppositely charged macromolecules leading to a liquid-liquid phase separation is called complex coacervation. Examples of complex coacervation between oppositely charged polyelectrolytes are numerous but complex coacervation involving two oppositely charged proteins was only described recently and it results from precise balance of repulsive and attractive interactions between the two proteins1. A better knowledge of the mechanisms of formation and stabilization of such system is essential to design biomaterial with optimized properties such as the encapsulation of bioactives. Here, we investigated the potentiality of two whey proteins, Beta-lactoglobulin (BLG) and Lactoferrin (LF), known for their ability to form complex coacervation2, to spontaneously co-assemble with vitamin B9. Under conditions of LF-BLG coacervation, in contrast to BLG, LF is able to interact with vitamin B9, forming specific nanoparticles3. The ability of such nanoparticles to form coacervates with BLG (B9-LF-BLG coacervates) was further investigated. B9-LF-BLG coacervation was assessed across a range of B9:Proteins mixing ratios and pH conditions by turbidity and phase contrast microscopy. Kinetics of their formation were monitored by light scattering technics. B9 entrapment was evaluated. Storage and time stability of the coacervates were assessed at various temperatures. B9-LF-BLG coacervates were formed in a narrow range of pH, protein concentration and stoichiometry. We evidenced that B9-LF-BLG coacervates exhibited an optimal entrapment of ≈ 10 mg B9/g of proteins. The B9-LF-BLG coacervates were stable over a two weeks storage time. The entrapment efficiency of B9 by the coacervates was found to be similar to that of other encapsulation techniques. Hence the B9-LF-BLG coacervates display useful potentialities as biocarriers for bioactives. They constitute new structured biomaterial based delivery systems with enhanced health benefit to formulate natural and functional ingredient.

Encapsulation of bioactive compounds such as vitamins and micronutrients is a great challenge to develop new functional foods. There is a growing demand from consumers for food products offering health benefits such as products enriched with vitamins. At the same time, consumers tend to favor natural food or products with minimal amount of additives. The encapsulation of bioactives usually resorts to extraneous components that are not natural constituents of the targeted food product. It could therefore be relevant to seek to encapsulate bioactive molecules by means of intraneous components that are natural constituents of the targeted food product. Among food constituents, food proteins are biopolymers that appear suitable for the transport and protection of several bioactives. Recent studies have reported the ability of two oppositely charged milk proteins, beta-lactoglobulin (BLG) and lactoferrin (LF), to spontaneously co-assemble to form heteroprotein complexes called “coacervates” (Anema et al., 2014; Tavares et al., 2015). Complex coacervation is a well-known phase separation between two oppositely charged macromolecules, into a concentrated phase of coacervates and dilute phase. It can be used as an encapsulation technique. In the literature, two general procedures can be found to encapsulate a compound by the complex coacervation of two biopolymers. The objective of this work is to investigate the potentialities of coacervates entirely made from food proteins to encapsulate a bioactive compound according to these procedures. We investigated the potentiality of BLG-LF coacervates to encapsulate the hydrophilic vitamin B9

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The complex effects of mechanical forces and growth factors on articular cartilage development still need to be investigated in order to identify optimal conditions for articular cartilage repair. Strictly controlled in vitro studies under modelled or space microgravity conditions can improve our understanding of the fundamental role of gravity in articular cartilage development. The main objective of this Topical Team is to use modelled microgravity as a tool to elucidate the fundamental science of cartilage regeneration. Particular attention is, therefore, given to the effects of physical forces under altered gravitational conditions, applied using controlled bioreactor systems, on cell metabolism, cell differentiation and tissue development. Specific attention is also directed toward the potential advantages of using magnetic resonance methods for the non-destructive characterisation of scaffolds, chondrocytes-polymer constructs and tissue engineered cartilage. 1. Articular Cartilage