Application of growth-phase based light-feeding strategies to simultaneously enhance Chlorella vulgaris growth and lipid accumulation

Abstract

Considering the variations of optimal light intensity required by microalgae cells along with growth phases, growth-phase light-feeding strategies were proposed and verified in this paper, aiming at boosting microalgae lipid productivity from the perspective of light conditions optimization. Experimental results demonstrate that under an identical time-averaged light intensity, the light-feeding strategies characterized by stepwise incremental light intensities showed a positive effect on biomass and lipid accumulation. The lipid productivity (235.49 mg L−1 d−1) attained under light-feeding strategy V (time-averaged light intensity: 225 μmol m−2 s−1) was 52.38% higher over that obtained under a constant light intensity of 225 μmol m−2 s−1. Subsequently, based on light-feeding strategy V, microalgae lipid productivity was further elevated to 312.92 mg L−1 d−1 employing a two-stage based light-feeding strategy V560 (time-averaged light intensity: 360 μmol m−2 s−1), which was 79.63% higher relative to that achieved under a constant light intensity of 360 μmol m−2 s−1.