A cell retention system composed of cellulose acetate hollow fiber membranes for cultivation of Dunaliella salina in a helical photobioreactor

Abstract

AbstractBackgroundOne of the challenges in commercial‐scale cultivation of Dunaliella salina is low biomass productivity and concentration. In addition, cultivations in wastewaters may encounter some nutrient limitations. Hence, there is a need for a cultivation system which is capable of continuous provision of nutrients while the cells are retained in the system. In this study, the feasibility of using a cell retention system (CRS) for increasing biomass productivity and concentration of D. salina was investigated. The CRS was composed of cellulose acetate hollow fiber membranes (HFMs) coupled with a helical photobioreactor.ResultsUsing the produced HFMs with mean pore size of 124 nm and overall porosity of 78.9%, the rejection of D. salina microalgae was as high as 93.2%. Continuous cultivation of D. salina in the helical photobioreactor at a dilution rate of 0.48 day−1 resulted in a biomass productivity (concentration) of 4.9 × 107 cells L−1 h−1 (2.7 × 106 cells mL−1). Interestingly, cultivation at the same initial dilution rate (0.48 day−1) in the helical photobioreactor coupled with the CRS resulted in a biomass productivity (concentration) of 9.3 × 107 cells L−1 h−1 (6.7 × 106 cells mL−1).ConclusionsThe results revealed the potential of the proposed system for enhancing biomass productivity by 90% and biomass concentration by more than twofold. The cultivation system is also proposed as a potential tool for cultivations in wastewaters. © 2019 Society of Chemical Industry