Microalgal biomass surface productivity optimization based on a photobioreactor model

Abstract

In this paper we predict and optimize the biomass surface productivity of microalgae in continuous culture under a constant light source. Surface biomass is identified as a key variable for assessing productivity: we provide both a mathematical and intuitive explanation. For reaching maximal productivities, biomass surface concentration must be such that growth at the culture bottom (assuming a planar geometry orthogonal to the light source) must be equal to respiration. Therefore the optimal biomass concentration depends both on the incident light and culture's depth. We then show how the chlorophyll/carbon ratio must also be carefully controlled to optimize light use in the photobioreactor. Finally, numerical results illustrate our theoretical approach.