Chlorella vulgaris heterotrophic colony development and interaction

Jing Zhang (1, 2) , Thi-Bich-Thuy Tran (1, 2) , Behnam Taidi (1, 2) , Pin Lu (1, 2) , Patrick Perre (1, 2)

1 CEBB - Centre Européen de Biotechnologies et Bioéconomie
2 LGPM - Laboratoire de Génie des Procédés et Matériaux

This study is a first outcome of a series of works on immobilized cultures of Chlorella vulgaris. Colonies were grown independently on solid media under heterotrophic conditions and their growth was followed by continuous three-dimensional microscopy and image analysis. The growth was assessed by 3D imaging using a structured light microscope and subsequent image processing. Based on the expressions proposed for the height and radius growth dynamics, we concluded that the colonies expanded at a constant rate in the horizontal direction and a decreasing rate in the vertical direction. A spherical cap best describes the shape of the colonies during the growth period. During development, the packing density of the cells in the colony was calculated to occupy 25-40% of the available space. The cell yield was initially much lower than published values and approached those values at the end, indicating that the glucose consumption was dependent on not only the growth and division of cells but also on the activity of old cells. Finally, no colony-colony intraspecies interaction was observed when two colonies were grown in proximity.

Mots clés: Chlorella vulgaris; Heterotrophic growth; 3D imagery; Colony growth model; Packing factor; Glucose consumption

Domaines: Sciences de l'ingénieur [physics]

Jing Zhang, Thi-Bich-Thuy Tran, Behnam Taidi, Pin Lu, Patrick Perre. Chlorella vulgaris heterotrophic colony development and interaction. Algal Research - Biomass, Biofuels and Bioproducts, 2020, 49, pp.101907. ⟨10.1016/j.algal.2020.101907⟩. ⟨hal-03140224⟩