Improving biomass growth of Nannochloropsis oceanica with electrical treatment

Abstract

In order to improve photosynthetic carbon fixation efficiency of microalgae, electrochemical responses of Nannochloropsis oceanica were investigated in terms of cell growth and physiological metabolism. A direct current with varying voltage was applied to N. oceanica during cultivation and effects on bio-regulation and electron transfer were assessed. When applied voltage increased from 0 V to 0.005 V and then to 0.5 V, the biomass dry weight first increased due to enhanced effective quantum yield of PSII photochemical energy conversion, chlorophyll a and nitrogen/orthophosphate uptake rates of microalgal cells, and then decreased due to disruption of cell structures. The optimal photosynthetic carbon fixation with 15% CO2 occurred at 0.005 V, resulting in a 32. 09% increase in microalgal biomass compared to that without electrical treatment.