Shear-enhanced membrane filtration of model and real microalgae extracts for lipids recovery in biorefinery context.

In this work, the hydrodynamic effects of rotating disk filtration (with maximum shear rates of 16,000 s and 66,000 s) were evaluated and compared with the crossflow filtration (16,000 s) in the recovery of lipids from a model solution that simulates the characteristics of Parachlorella kessleri aqueous extracts. Four polymeric membranes were tested. The PAN 500 kDa membrane along with the rotating disk filtration presented the best performances for lipid concentration and coalescence.

Mechanical cell disruption of Parachlorella kessleri microalgae: Impact on lipid fraction composition.

Samples of nitrogen-starved Parachlorella kessleri containing intact cells (IC), cells ground by bead milling (BM), and cells subjected to high-pressure cell disruption (HPD), together with their supernatants after centrifugation, were compared for granulometry and lipid profiles. The effects of disruption on the lipid profile and organisation were evaluated. The quantity of lipids available for extraction increased with disruption, and up to 81% could be recovered in supernatants after centrifugation, but a marked reorganization occurred.

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.

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.

[Hemoptysia and postoperative pulmonary edema after general anesthesia for amygdalectomy].

Acute postoperative negative pressure pulmonary edema with hemoptysia as a complication of general anesthesia is seldom. Its is related to an obstacle on airway, with important negative intrathoracic depression during inspiration leading to pulmonary edema and hemoptysia. Physiopathology and treatment of such complication have been discussed.