Luc Marchal

University of Nantes | UNIV Nantes · Process and Bioprocess Engineering

Nitrogen limitation and changing solar conditions are both known to affect triacylglycerol (TAG) production in microalgae. This work investigates the optimization of TAG production with a continuous nitrogen‐limited culture of Nannochloropsis gaditana in simulated day‐night cycles. The effect of day‐night cycles was firstly investigated in nitrogen...

The aim of this work is to track and optimize lipid recovery from Nannochloropsis gaditana in wet extraction operations. No significant differences in biomass concentration were found when disrupting microalgal suspensions of up to 30 g/L dry weight, but disruption efficiency differed depending on their physiological states. It took 5.8 min in a be...

Energy-storage metabolites such as neutral lipids and carbohydrates are valuable compounds for liquid biofuel production. The aim of this work is to elucidate the main biological responses of two algae species known for their effective energy-rich compound accumulation in nitrogen limitation and day–night cycles: Nannochloropsis gaditana, a seawate...

This work investigates the potential of pulsed electric energy (pulsed electric fields (PEF) and high-voltage electrical discharges (HVED)) and high pressure homogenization (HPH) for extraction of bio-molecules from Parachlorealla kessleri. The applied procedures included individual pulsed electric energy (PEF, HVED), HPH treatments, and their comb...

Integration of solid-liquid and liquid-liquid extractions, SLE and LLE, respectively, for selective recovery of Origanum vulgare subsp. glandulosum phenolics was studied. A Two-Phase Solvent Extraction (TPSE) was performed by maceration at room temperature using a green biphasic solvent system and compared to Centrifugal Partition Extraction (CPE)....

Aqueous extraction assisted by pulsed electric energy (PEE) and ultrasonication (US) were tested for three microalgal species (Nannochloropsis sp., Phaeodactylum tricornutum, Parachlorella kessleri). The PEE treatments were applied using pulsed electrical fields (PEF) and high voltage electrical discharges (HVED) modes. The extraction degrees of ca...

Two-step procedure with the initial aqueous extraction from raw microalgae Nannochloropsis oculata and secondary organic solvent extraction from vacuum dried (VD) microalgae were applied for selective recovery of bio-molecules. The effects of preliminary aqueous washing and high voltage electrical discharges (HVED, 40 kV/cm, 4 ms pulses) were teste...

The effects of physical treatments (pulsed electrical fields (PEF), high voltage electrical discharges (HVED) and ultrasonication (US)) on aqueous extraction of carbohydrates and proteins, and ethanolic extraction of chlorophyll a from three microalgal species (Nannochloropsis sp., P. tricornutum and P. kessleri) have been studied. The total energy...

A multi-step aqueous and non-aqueous extraction procedure was applied to recovery bio-molecules from Phaeodactylum tricornutum. The process include that physical pre-treatments (high voltage electrical discharges (HVED, 40 kV/cm, 1–8 ms, HVED samples) or high pressure homogenization (HPH, 1200 bar, 10 passes, P samples)) (1st step); aqueous extract...

The disintegration efficiencies of microalgal Parachlorella kessleri cells by ultrasonication (US) and high pressure homogenization (HPH) treatments were investigated. The applied procedures included individual US, individual HPH, or combined US followed by HPH treatments. The test concentrations of cell suspensions were 1% and 10% dry matter. The...

Microalgae of Nannochloropsis sp. present valuable source of bio-molecules (pigments, lipids, proteins) that have nutritional potential for the prevention and treatment of human diseases. Moreover, some species of Nannochloropsis are the promising sources of biofuels and excellent candidates for the replacement of classical biofuel crops. This revi...

Treatments with high-voltage electrical discharges (HVED) and high-pressure homogenization (HPH) were studied and compared for the release of ionic components, carbohydrates, proteins, and pigments from microalgae Parachlorella kessleri (P. kessleri). Suspensions (1% w/w) of microalgae were treated by HVED (40 kV/cm, 1–8 ms) or by HPH (400–1200 bar...

For biodiesel applications, microalgae and especially Nannochloropsis sp. are considered as a promising feedstock for lipid production. Main issues are high lipid productivity, but also robust and energy efficient downstream processes. In the biorefinery process, cellular mechanical pretreatment and solvent extraction are investigated nowadays to a...

The industrial potential of pH-zone refining centrifugal partition chromatography has been evaluated by studying the purification of pharmaceutical ingredients at the pilot scale. For the first time, a scale up methodology based on both column capacity and mass transfer efficiency as invariants was developed. The purification of catharanthine and v...

The invention relates to a method for producing membrane polysaccharides from an organism selected from a micro-organisms, unicellular organims and filamentous fungi, said method comprising at least one step of extracting said membrane polysacchraides as well as a smaller-scale extraction of soluble proteins, by mechanical of said organism in a bal...

The method for treating a microalgal biomass, characterized in the following steps: having a microalgal biomass comprising at least 15% by weight of lipids relative to the total weight of the biomass and having a dry matter concentration of between 1 g/l and 200 g/l, milling said biomass by a bead mill, operated under the following conditions: the...

Implementation of continuous processes for production of fine chemicals and pharmaceuticals is an efficient way for process intensification. This study aims at demonstrating the potential of a Centrifugal Partition Chromatography (CPC) apparatus as a novel type of intensified reactor (termed Centrifugal Partition Reactor, CPR) for biphasic (water-o...

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. Operating parameters effects were analyzed and...

The study was aimed at investigation of the potential of pulsed electric field (PEF) pre-treatment as a preliminary step of pH-assisted aqueous extraction of algae components from microalgae Nannochloropsis suspensions. The PEF and sonication (S) were compared as pretreatment methods. They were applied at normal (pH = 8.5) and basic (pH = 11) condi...

A model based on mass transfer resistances and acid-base equilibriums at the liquid-liquid interface was developed for the pH-zone refining mode when it is used in countercurrent chromatography (CCC). The binary separation of catharanthine and vindoline, two alkaloids used as starting material for the semi-synthesis of chemotherapy drugs, was chose...

Centrifugal Partition Chromatography (CPC) is a separation process based on the partitioning of solutes between two partially miscible liquid phases. There is no solid support for the stationary phase. The centrifugal acceleration is responsible for both stationary phase retention and mobile phase dispersion. CPC is thus a process based on liquid-l...

This work studies the potential of the pulsed electric field (PEF) assisted extraction of nutritionally valuable compounds from microalgae Nannochloropsis spp. using the binary mixture of organic solvents (dimethyl sulfoxide, DMSO and ethanol, EtOH) and water. The one-stage (EI) and two stage (EII) extraction procedures were compared. The procedure...

The preindustrial R&D facility AlgoSolis will be devoted to investigations in representative conditions of industrial applications of microalgae (outdoor production, large-scale) and to the integration of technological bricks defining an industrial exploitation of microalgae [cultivation systems (25 lines), harvesting and downstream processing of b...

Marine ressources contain various compounds such as proteins and pigments, lipids or carbohydrates that are highly valuable in food and feed, cosmetic or nutraceutical sectors ... As reliable and environmental technologies, membranes processes (ultra-,nanofiltration...) have found many uses to concentrate, desalt or pre-purify these compounds . Sev...

This work studies the extraction of intracellular components from microalgae Nannochloropsis sp. with application of different cell disruption techniques, including pulsed electric field (PEF) (20kV/cm, 1-4ms, 13.3-53.1kJ/kg), high voltage electrical discharge (HVED) (40kV/cm, 1-4ms, 13.3-53.1kJ/kg), ultrasonication (USN) (200W, 1-8min, 12-96kJ/kg)...

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 48 h, the redu...

Synthetic hydrophobic non-ionizable peptides are not soluble in most common solvents and are thus difficult to purify by preparative reversed-phase HPLC, normally used for industrial production. The challenge exists to develop alternative purification chromatographic processes using suitable solvents and providing good yields, high purity and suffi...

The microalga Porphyridium cruentum is known to produce many components of interest. One of them is B-Phycoerythrin (B-PE), a water-soluble intracellular pigment used as an immunofluorescent probe. Current methods to extract this molecule involve total cell disruption and lead to a mix of all the water-soluble components. Subsequently, the pigment...

A comparative study between "alternative" extraction processes such as centrifugal partition extraction (CPE), supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) and classical solid/liquid used in the laboratory are currently focusing on the efficiency (selectivity and productivity) to obtain bioactive phenolic compounds f...

In this work the extraction of EPSs from culture media of P. cruentum, by dialysis, solvent-precipitation with 3 polar alcohols (methanol, ethanol and isopropanol) and membrane separation techniques has been studied. Diafiltration (DF) using a membrane with a 300 kDa molecular weight cut off was the most efficient technique compared to solvent-extr...

Centrifugal partition extraction (CPE), close to centrifugal partition chromatography, put in contact in a continuous way two immiscible liquid phases. This work presents early experiments on CPE use for solid-liquid-liquid extraction. It was applied to the direct treatment of culture broth for metabolites recovery. Torularhodin is one of the carot...

The aim of this article was to evaluate the influence of the column design of a hydrostatic support-free liquid-liquid chromatography device on the process efficiency when the strong ion-exchange (SIX) development mode is used. The purification of p-hydroxybenzylglucosinolate (sinalbin) from a crude aqueous extract of white mustard seeds (Sinapis a...

The potential of centrifugal partition extraction (CPE) combined with the ion-pair (IP) extraction mode to simultaneously extract and purify natural ionized saponins from licorice is presented in this work. The design of the instrument, a new laboratory-scale Fast Centrifugal Partition Extractor (FCPE300(®)), has evolved from centrifugal partition...

The effect of blanching by ohmic heating (OH) on the kinetics of osmotic dehydration of strawberries was studied. Ohmic heating parameters obtained at two temperatures (65 and 85°C). The osmotic dehydration (OD) parameters are the temperature (26 and 37°C) and the sucrose in osmotic solution (30–70°B). An approximate solution of Fick’s law for unst...

Vacuum impregnation (VI) and ohmic heating (OH) pre-treatments with and without addition of citric acid were used to enhance the mass transfer kinetics during osmotic dehydration (OD) of apple cubes. The VI with citric acid made the following OH treatment more homogeneous and equilibrated the fruit and syrup temperatures. The water loss (WL) and su...

The effect of blanching by ohmic heating (OH) on the damage to apple tissues and subsequent osmotic dehydration kinetics was investigated. Apple cubes were heated ohmically to various blanching scales. Heating temperature and duration were, respectively, 60–95 ± 2°C and 0–6 min. After cooling, the treated samples were put into sucrose solutions (70...

A dedicated CPC prototype permits direct flow pattern visualization in the partition cells of a CPC column. It was used to understand "flooding", a frequent phenomenon associated with large injections. A general strategy was developed to optimize the injection step in the framework of a particular preparative separation: the purification of 5-n-alk...

Centrifugal partition chromatography (CPC) was introduced in 1982 by Sanki Eng. And for almost 20 years this company remained the only one manufacturing such an apparatus. A CPC instrument or a CPC column is a series of channels linked in cascade by ducts and aligned in cartridges or disks in a circle around a rotor; setting the rotor in motion sub...

A centrifugal partition chromatography (CPC) is a one-axis centrifugal system operating with two rotary seals. A CPC column is a series of cells linked in a cascade by ducts and regularly disposed around a rotor as cartridges or disks, and submitted to a constant centrifugal acceleration generated by a rotation. This chapter presents the first assu...

Centrifugal partition chromatography (CPC) is a support-free liquid–liquid separation process that depends for efficiency on the behavior of the two liquid phases. Hydrodynamics of phases was studied according to flow rate and centrifugal acceleration, using a transparent column and a stroboscopic video system. For the heptane-methanol two-phase sy...

Visualization of flow patterns in centrifugal partition chromatography (CPC) was performed with an asynchronous camera and a stroboscope triggered by the CPC rotor, allowing a channel to be selected and observed regardless of rotational speed. Three main types of flow states were noted as a function of rotational speed and flow-rate: jets stuck alo...