Separation of microalgae with different lipid contents by dielectrophoresis

Abstract

In this study, the effect of the solution conductivity on the behavior of microalgal cells (Chlorella) with different lipid contents under a non-uniform electric field was investigated. It was found that, for the algal cells with 11wt% lipid content, the crossover frequency is between 2 and 10MHz when the solution conductivity is within 1.4 and 2.95mS/cm, and increases as the solution conductivity increases. As to the microalgal cells with 45wt% lipid content, they experienced negative DEP at frequency below 20MHz when the solution conductivity is within 2.06 and 2.95mS/cm. However, positive DEP was observed when the solution conductivity becomes 1.4mS/cm. In a mixture of the algal cells, those with different lipid contents were successfully separated by DEP at solution conductivity of 2.95mS/cm and frequency of 20MHz.