Biomass productivity and characterization of Tetradesmus obliquus grown in a hybrid photobioreactor

Abstract

In this study, the effects of CO₂ addition on the growth performance and biochemical composition of the green microalga Tetradesmus obliquus cultured in a hybrid algal production system (HAPS) were investigated. The HAPS combines the characteristics of tubular photobioreactors (towards a better carbon dioxide dissolution coefficient) with thin-layer cascade system (with a higher surface-to-volume ratio). Experimental batches were conducted with and without CO₂ addition, and evaluated in terms of productivity and biomass characteristics (elemental composition, protein and lipid contents, pigments and fatty acids profiles). CO₂ enrichment positively influenced productivity, and proteins, lipids, pigments and unsaturated fatty acids contents in biomass. The HAPS herein presented contributes to the optimization of microalgae cultures in open systems, since it allows, with a simple adaptation-a transit of the cultivation through a tubular portion where injection and dissolution of CO₂ is efficient-to obtain in TLC systems, greater productivity and better-quality biomass.

Keywords: Lipids; Microalgal biomass; Thin-layer cascade; Tubular photobioreactor.