Rheological properties of suspensions of the green microalga Chlorella vulgaris at various volume fractions

Abstract

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

A microscopic Gibbs field model for the macroscopic yielding behaviour of a viscoplastic fluid

“…The rheological flow curves measured for a suspension of spherical and electrically charged non-motile micro algae (Chlorella Vulgaris) reveal an abrupt solid-fluid transition and exhibit a strong hysteresis even in the limit of very slow forcing, see Fig. 11 in 5 . In the case of a Carbopol gel where the microscopic interactions are presumably weaker than the interactions between electrically charged Chlorella cell a much smoother solid fluid transition is observed and, in the asymptotic limit of steady forcing, the hysteresis effects become negligibly small, 13 .…”

“…Micrographs of several yield stress materials: (a) commercial shaving gel (Gillette Series) (b) mayonnaise (Carrefour, France) (c) 5% bentonite in water (d) suspension of Chlorella Vulgaris unicellular micro alga (reproduced from Ref 5. ).…”

Absorption and scattering by fractal aggregates and by their equivalent coated spheres

“…The authors hypothesized that aggregation occurred at large cell concentration due to the proximity of the cells to one another. Since larger microalgae cells possess a larger surface charge density compared to smaller cells, the electrostatic repulsion between larger cells is much stronger than that between a large and a small cell [18]. This leads to aggregation of the smaller cells in the space created by the electrostatic repulsion between the larger cells.…”

“…EPS production is part of a protection mechanism activated in response to environmental conditions such as limited Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jqsrt illumination [15], non-optimal temperature [16], high salinity [16], and limited nutrient availability [17]. In addition, a recent study demonstrated reversible cell aggregation in concentrated Chlorella vulgaris cultures used for protein, starch, and lipid production [18]. The authors hypothesized that aggregation occurred at large cell concentration due to the proximity of the cells to one another.…”

Microscopic flows of suspensions of the green non-motile Chlorella micro-alga at various volume fractions: Applications to intensified photobioreactors

“…A more recent study of the rheological behaviour of suspensions of Chlorella Vulgaris with volume fractions spanning a wide range was reported in Ref. [19].…”