Rapid induction of edible lipids in Chlorella by mild electric stimulation.

• Rapid induction of lipids in Chlorella by mild electric treatment (31 mA and 4 h). • 2.1-fold improvement of triacylglycerol (TAG) content relative to the control. • Promotion of biosynthesis of polyunsaturated linoleic and linolenic acids. • Electric lipid stimulation through transformation and de novo biosynthesis. In this work, a new stress-based method for rapid induction of triacylglycerol (TAG) and total and polyunsaturated fatty acid accumulations in Chlorella sp. by mild electric stimulation is presented. When a cathodic current of 31 mA (voltage: 4 V) was applied to the algal cells for 4 h, the TAG content of the electro-treated cells was sharply increased to a level 2.1 times that of the untreated control. The contents of the polyunsaturated linoleic (C18:2n6) and linolenic (C18:3n3) acids in the electro-treated cells were also 36 and 57% higher than those in the untreated cells, respectively. Cyclic voltammetry and various biochemical analyses indicate that TAG and fatty acid formations are electro-stimulated via de novo fatty acid biosynthesis and metabolic transformation in the Chlorella cells. [ABSTRACT FROM AUTHOR]