Lipid accumulation properties of Chlorella vulgaris and Scenedesmus obliquus in membrane photobioreactor (MPBR) fed with secondary effluent from municipal wastewater treatment plant

In this study, green algae Chlorella vulgaris and Scenedesmus obliquus were cultured in membrane photobioreactor (MPBR) with continuous flow of secondary effluent from the municipal wastewater treatment plant (MWWTP) to study the lipid accumulation properties of microalgae cultured in MPBR with low nutrient culture medium. Lipid contents in algal cells were determined daily by sulpho-phospho-vanillin (SPV) colorimetric method. The results indicated that the lipid cell contents of Chlorella vulgaris and Scenedesmus obliquus were strongly related to their growth phase in the reactors. In the stationary growth phase, the average lipid cell contents of Chlorella vulgaris and Scenedesmus obliquus were 29.8% and 36.9%, respectively, much higher than that achieved during logarithmic growth phase (16.3% for Chlorella vulgaris and 20.2% for Scenedesmus obliquus), suggesting that microalgae with higher lipid cell content can be obtained by controlling the growth of microalgae in the MPBR at a stationary phase. The results of this study are of significance for optimizing the operation of MPBR in order to realize the high efficiency of algal lipid production.