Enhancement of microalga Haematococcus pluvialis growth and astaxanthin production by electrical treatment

•Electrical treatment was deployed to enhance the growth of microalga Haematococcus.•Direct electrical treatment of H. pluvialis cells resulted in growth-promoting effects.•Periodic electrical treatment was shown to be more effective.•Our results provide a foundation to increase the productivity of H. pluvialis. In this study, we investigated the effects of electrical treatment on Haematococcus pluvialis growth. The slow growth of H. pluvialis is a major limitation for its mass production. We discovered that electrical treatment may promote the growth of H. pluvialis. To evaluate optimal growth-promoting conditions, the algal growth rate was investigated at various voltages. The optimum current was identified as 100 mA (voltage: 25 V). In comparison with the non-treated cells, those subjected to electrical treatment showed a 1.2 fold increase in cell density. Further experiments confirmed the direct impact of electrical treatment on the growth of H. pluvialis. The periodic application of electrical voltage resulted in a significant increase in the dry weight and astaxanthin production. The astaxanthin content in the periodic application of electrical treatment was 32.6 mg/L, which was a 10% increase compared to those in the non-treated controls. This strategy may serve as a novel approach to enhance H. pluvialis growth as well as astaxanthin production.