Salinity-induced cellular cross-talk in carbon partitioning reveals starch-to-lipid biosynthesis switching in low-starch freshwater algae

• DOI: 10.1016/j.biortech.2017.11.067
• Publication Date: 2017-11-24T09:33:34Z
• Authors: Lijie Zhang; Haiyan Pei; Shuaiqi Chen; Liqun Jiang; Qingjie Hou; Zhigang Yang; Ze Yu
• Keywords: Salinity; 0211 other engineering and technologies; Fresh Water; Starch; Chlorella; 02 engineering and technology; Lipids; Carbon; 6. Clean water; Biofuels; Microalgae; Biomass

Salinity stress has been verified to be a successful approach to enhance lipid production in high-starch marine algae, and salinity-induced carbon flow switching has been proposed as an algal response specific to brackish water. With the aim of testing this assumption, Chlorella sorokiniana SDEC-18, a low-starch freshwater alga, was grown in BG11 medium with NaCl addition at various concentrations (0, 2, 5, 10, 20, and 30 g/L). The results showed that salinity stress promoted carbon redistribution and starch conversion to lipid. The most desirable lipid productivity of 19.66 mg/L·d occurred in the medium with 20 g/L NaCl, about 2.16 times as high as that in the BG11 medium control. Moreover, microalgae with salinity stress were able to produce biodiesel with a more suitable cloud point, due to a decrease in the saturated fatty acid content. This therefore confirms that low-starch freshwater microalgae can also carry out salinity-induced carbon flow switching.