POTRA domains of the TamA insertase interact with the outer membrane and modulate membrane properties.

The outer membrane (OM) of gram-negative bacteria serves as a vital organelle that is densely populated with OM proteins (OMPs) and plays pivotal roles in cellular functions and virulence. The assembly and insertion of these OMPs into the OM represent a fundamental process requiring specialized molecular chaperones. One example is the translocation and assembly module (TAM), which functions as a transenvelope chaperone promoting the folding of specific autotransporters, adhesins, and secretion systems.

Recovery of Water-Soluble Compounds from .

This work aims at studying the techno-economic feasibility to produce an extract, at a small industrial-production scale, from a 's paste, in view of cosmetic applications. The paste was first thawed, diluted and centrifuged to get a crude water extract. Then, two successive stages of membrane filtration were carried out: the first one to essentially remove/retain the particles (cellular debris) by microfiltration and the second one to concentrate (ultrafiltration) the soluble compounds of the permeate from the previous step.

Filterability of exopolysaccharides solutions from the red microalga by tangential filtration on a polymeric membrane.

The red microalga is exploited industrially for its exopolysaccharides (EPS) and pigments production. EPS produced by are partially released and dissolved into the surrounding environment, they can be recovered from the culture medium after removing the cells. This paper presents a parametric study of the ultrafiltration of EPS solutions on organic membrane.

Effect of filtration rate on coal-sand dual-media filter performances for microalgae removal.

This study tested the efficiency of granular filtration using a bilayer sand filter for microalgae removal from culture dilutions ranging from 10,000 to 17,000 cells/mL. The objective is to evaluate the removal capacity of the filter without chemical coagulation. Two filter media, sand and anthracite, with mean grain sizes of 0.

Porous membranes for ballast water treatment from microalgae-rich seawater.

The ballast waters from ships pose a major threat to oceans, notably because of the spread of microorganisms. The present study evaluates the techno-economic feasibility of implementing the membrane process to remove microalgae from seawater to be ballasted in a single step during planktonic bloom. The optimal conditions for the microfiltration of complex and reproducible synthetic seawater are a permeate flux and specific filtered volume of 100 L.

Optimization of bead milling parameters for the cell disruption of microalgae: process modeling and application to Porphyridium cruentum and Nannochloropsis oculata.

A study of cell disruption by bead milling for two microalgae, Nannochloropsis oculata and Porphyridium cruentum, was performed. Strains robustness was quantified by high-pressure disruption assays. The hydrodynamics in the bead mill grinding chamber was studied by Residence Time Distribution modeling.

One-step purification of R-phycoerythrin from the red edible seaweed Grateloupia turuturu.

A one-step chromatographic method for the purification of R-phycoerythrin (R-PE) of Grateloupia turuturu Yamada is described. Native R-PE was obtained with a purity index of 2.89 and a recovery yield of 27% using DEAE-Sepharose Fast Flow chromatography with a three-step increase in ionic strength.

Marennine, promising blue pigments from a widespread Haslea diatom species complex.

In diatoms, the main photosynthetic pigments are chlorophylls a and c, fucoxanthin, diadinoxanthin and diatoxanthin. The marine pennate diatom Haslea ostrearia has long been known for producing, in addition to these generic pigments, a water-soluble blue pigment, marennine. This pigment, responsible for the greening of oysters in western France, presents different biological activities: allelopathic, antioxidant, antibacterial, antiviral, and growth-inhibiting.

Harvesting Chlorella vulgaris by natural increase in pH: effect of medium composition.

The freshwater microalga Chlorella vulgaris was harvested by autoflocculation resulting from the precipitation of magnesium or calcium compounds induced by a slow increase in pH in the absence of CO2 input. Autoflocculation was tested in two culture media with, respectively, ammonium (NH4+) and nitrate (NO3-) ions as nitrogen source. The culture pH increased because of photosynthesis and CO2 stripping.

Seawater ultrafiltration: role of particles on organic rejections and permeate fluxes.

The role of natural compounds of seawater and added particles on mechanisms of membrane fouling and organic matter rejection has been investigated. Ultrafiltration (100 kDa) has been conducted in both dead-end (out/in) and tangential (in/out) modes on polysulfone hollow fibre membranes. The permeate fluxes are approximately three times higher for tangential ultrafiltration than for dead-end ultrafiltration without differences between settled and non-settled seawaters (NS-SWs) (51-55 L h(-1) m(-2) for tangential and 17-22 L h(-1) m(-2) for dead-end ultrafiltration).

Physicochemical factors affecting the stability of two pigments: R-phycoerythrin of Grateloupia turuturu and B-phycoerythrin of Porphyridium cruentum.

Phycoerythrin is a major light-harvesting pigment of red algae, which could be used as a natural dye in foods. The stability of R-phycoerythrin of Grateloupia turuturu and B-phycoerythrin of Porphyridium cruentum in relation to different light exposure times, pHs, and temperatures was studied. Regarding the light exposure time, after 48h, the reduction in concentrations of B-phycoerythrin and R-phycoerythrin were 30±2.

The culture of Chlorella vulgaris in a recycled supernatant: effects on biomass production and medium quality.

Reusing supernatant of microalgae culture medium can have inhibitory or toxic effects on the biomass production because of the release of organic metabolites by cells in the culture medium during their growth. This work investigated the impact of Chlorella vulgaris medium recycling on culture productivity, cells quality and accumulation of excreted metabolites in the culture medium. No significant impact on the C.

Development and validation of a minimal growth medium for recycling Chlorella vulgaris culture.

When microalgae culture medium is recycled, ions (e.g. Na(+), K(+), Ca(2+)) that were not assimilated by the microalgae accumulate in the medium.

Performance of a sand filter in removal of micro-algae from seawater in aquaculture production systems.

In this study, a sand filter was used to remove micro-algae from seawater feeding aquaculture ponds. A lab-scale sand filter was used to filter 30,000 cells/mL of Heterocapsa triquetra suspension, a non-toxic micro-alga that has morphological and dimensional (15-20 microm) similarities with Alexandrium sp., one of the smallest toxic micro-algae in seawater.

Estimated costs of implementation of membrane processes for on-site greywater recycling.

Greywater reuse inside buildings is a possible way to preserve water resources and face up to water scarcity. This study is focused on a technical-economic analysis of greywater treatment by a direct nanofiltration (NF) process or by a submerged membrane bioreactor (SMBR) for on-site recycling. The aim of this paper is to analyse the cost of recycled water for two different configurations (50 and 500 inhabitants) in order to demonstrate the relevance of the implementation of membrane processes for greywater recycling, depending on the production capacity of the equipment and the price of drinking water.

Membrane process treatment for greywater recycling: investigations on direct tubular nanofiltration.

On-site greywater recycling and reuse is one of the main ways to reduce potable water requirement in urban areas. Direct membrane filtration is a promising technology to recycle greywater on-site. This study aimed at selecting a tubular nanofiltration (NF) membrane and its operating conditions in order to treat and reuse greywater in buildings.

Impact of ultrafiltration and nanofiltration of an industrial fish protein hydrolysate on its bioactive properties.

Background: Numerous studies have demonstrated that in vitro controlled enzymatic hydrolysis of fish and shellfish proteins leads to bioactive peptides. Ultrafiltration (UF) and/or nanofiltration (NF) can be used to refine hydrolysates and also to fractionate them in order to obtain a peptide population enriched in selected sizes. This study was designed to highlight the impact of controlled UF and NF on the stability of biological activities of an industrial fish protein hydrolysate (FPH) and to understand whether fractionation could improve its content in bioactive peptides.

Formulation of synthetic greywater as an evaluation tool for wastewater recycling technologies.

On-site greywater recycling is one of the main ways of preserving water resources in urban or arid areas. This study aims to formulate model synthetic greywater (SGW) in order to evaluate and compare the performances of several recycling processes on a reproducible effluent. The formulated SGW is composed of septic effluent to provide indicators of faecal contamination, and technical quality chemical products to simulate organic pollution of greywater.

Enzymatic hydrolysis of cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) viscera using commercial proteases: effects on lipid distribution and amino acid composition.

Total lipid and phospholipid recovery as well as amino acid quality and composition from cuttlefish (Sepia officinalis) and sardine (Sardina pilchardus) were compared. Enzymatic hydrolyses were performed using the three proteases Protamex, Alcalase, and Flavourzyme by the pH-stat method (24 h, pH 8, 50 degrees C). Three fractions were generated: an insoluble sludge, a soluble aqueous phase, and an oily phase.

Recovery of valuable soluble compounds from washing waters generated during small fatty pelagic surimi processing by membrane processes.

This work focuses on the treatment of washing waters coming from surimi manufacturing using ultrafiltration technology at a laboratory scale. Four membrane materials (poly-ether sulfone, polyacrilonytrile, poly vinylidene fluoride and regenerated cellulose) and 5 Molecular Weight Cut-Off (from 3 to 100 kDa) have been studied at bench laboratory scale using the pilot Rayflow 100, commercialised by Rhodia Orelis. The investigation deals with the ability for membranes to offer a high retention of biochemical compounds (proteins and lipids).

Arthrospira platensis harvesting with membranes: fouling phenomenon with limiting and critical flux.

The present work deals with the harvesting of Arthrospira platensis (Spirulina) from a diluted culture medium. This cyanobacterium was retained by the European Space Agency as food supply for long term manned spatial missions, and integrated in the MELiSSA project: an artificial microecosystem which supports life in space. Membranes techniques seem to be adapted to efficiency, reliability and safety constraints, even if a well-known limitation is the progressive fouling and permeation flux decrease.

The role of exopolysaccharides in fouling phenomenon during ultrafiltration of microalgae (Chlorellasp. and Porphyridium purpureum): advantage of a swirling decaying flow.

Ultrafiltration of two microalgae species, Chorellasp. and Porphyridium purpureum, has been performed in two filtration units of different configurations: a module generating a classical tangential-plane flow and another one inducing a swirling decaying flow. The swirling motion is generated by a unique tangential inlet at the bottom of an annulus.

Coupling ultrafiltration with an activated carbon cloth for the treatment of highly coloured wastewaters: a techno-economic study.

This work investigates the coupling of a membrane technique, ultrafiltration, with a recent adsorbent, activated carbon cloth for the treatment of industrial highly coloured wastewaters. A first experimental part shows the high treatment ability of this process for fountain-pen inks effluents arising from the rinsing of vats in which inks were produced. Whereas ultrafiltration enables more than 97% of colour removal, COD and DOC are not completely retained and a residual value of 1,700 mg l(-1) of DOC is obtained in the permeate.

Stabilized landfill leachate treatment by combined physicochemical-nanofiltration processes.

Landfill leachate is a complex wastewater which the composition and concentration of contaminants are influenced by the type of waste deposited and the age of landfill. In the last years, several processes or process combinations were developed and tested to reach requirements for the discharge of leachate. Among the new processes, membrane processes are considered as promising: reverse osmosis is one of the most widely used treatment in the Northwestern European countries and nanofiltration is gained in popularity during the last 5 years.

Effects of shear on two microalgae species. Contribution of pumps and valves in tangential flow filtration systems.

The circulation of microorganisms in tangential flow filtration systems induces perturbations and then the damage of brittle cells. This work is focused on the shearing of two marine microalgae species (Skeletonema costatum and Haslea ostrearia), both largely cultivated in western France (Région des Pays de la Loire). We have studied the effects of the circulation of these cells in pumps and valves.