A review of strategies enhancing lipid production from Chlorella: Progress and comparative analysis

Abstract

Various strategies have been developed to improve lipid production in microalgae. However, owing to the various microalgal species and experimental conditions used in studies, identifying the effectiveness of lipid enhancement strategies just by comparing lipid yields is challenging. The key to identifying effective strategies is to investigate the increase in lipid yield caused by different strategies based on the same microalgal species. This review focuses on the oleaginous microalga Chlorella sp. In addition to the statistical lipid yield of Chlorella sp. under different strategies, the corresponding lipid increments were calculated and compared. A comprehensive analysis revealed that regulating the carbon to nitrogen (C/N) ratio is the most effective approach for enhancing lipid production. Strategies centered around nitrogen limitation, such as nitrogen limitation coupled with phosphorus repletion and exogenous phytohormones, also show feasibility. Moreover, the commonly used stage conversion time in the two-stage cultivation strategy is challenging, suggesting its potential impracticality.