Effect of Hydrodynamic Conditions of Photobioreactors on Lipids Productivity in Microalgae

Abstract

This research presents the effect of hydrodynamic conditions at different rates of aeration (1.4, 1.8, and 2.3 vvm) and the geometry of two photobioreactors with internal lighting on lipid productivity and other parameters of Chlorella vulgaris. A two-step nitrogenreduction cultivation mode was applied for promoting lipid accumulation. The inoculum was cultivated initially at 90 mg L −1 N-NH 4 + , and at the end of the exponential phase, it was fed to 11 L photobioreactor at 20 mg L −1 of N-NH 4 +. The results showed that with similar aeration rates, the hydrodynamic regime in both photobioreactors was different. However, the increase in shear rate and agitation did not cause cell damage or photoinhibition. The maximum cell growth was 12 × 10 6 cells mL −1. The highest consumption of nitrogen was 19% and shear rates were of 120-340 s −1. The highest lipid productivity was reached in bubble column at 1.8 vvm with 0.650 mg•L −1 d −1 .

The Application of Poly-dispersed Flow on Rectangular Airlift Photobioreactor Mixing Performance

“…The microalgae cultivation can be done in open systems such as open-ponds or closed systems named photobioreactor 8) . Both systems require the intensity of light as a critical factor affecting the growth 9) .…”

Recommended turbulent energy dissipation rate for biomass and lipid production of Scenedesmus obliquus in an aerated photosynthetic culture system

“…It is generally believed that aeration directly affects the hydrodynamic conditions in the culture medium while changing the concentrations of CO 2 . Some studies have shown that hydrodynamic conditions affect the growth, Responsible Editor: Ta Yeong Wu physiology, and lipid content of microalgae (Heredia et al 2018;Lee et al 2019). Hondzo and Wang (2002) found that Spirogyra had the largest biomass when the shear velocity was 7 × 10 −3 m s −1 .…”