Lipid extraction from microalgae cell using persulfate-based oxidation

In this study, persulfate, a solid-type oxidant, was adopted as a substitute for hydrogen peroxide in extracting lipid from microalgae biomass. Microalgae cells were concentrated at pH 3 and with 200mg/L of ferric chloride, conditions which can activate oxidants such as hydrogen peroxide and persulfate. At a persulfate concentration of 2mM and a reaction temperature of 90°C, exceedingly high extraction efficiency over 95% was obtained, which was higher than with 0.5% hydrogen peroxide at the same temperature. This result showed that persulfate is sufficiently powerful and incomparably cheap enough to replace the potent yet expensive oxidant. It appears that combining iron-based coagulation and persulfate-based lipid extraction is indeed a competitive approach that can possibly lighten the process burden for the microalgae-derived biodiesel production.