Enhancement of Lutein Yield from Coagulated Chlorella sp. ESP-6 with Sodium Hypochlorite

Abstract

Applying coagulant such as polyaluminum chloride (PACl) or chitosan can improve harvesting efficiency of microalgae from broth. However, the coagulant molecules have affinity to lutein molecules, so coagulation reduces the lutein yield. This work proposed the addition of NaOCl with coagulant for enhancing lutein recovery from Chlorella sp. ESP-6 cells. Adding PACl or chitosan largely enhanced membrane filtration flux but had no effects on residual solid contents of filter cake. NaOCl released insoluble substances from the biomass matrix and deteriorated soluble lutein in water. When both NaOCl and coagulant were presented, the NaOCl helped to release the lutein out of the biomass, while the PACl and chitosan molecules assisted in capturing the OCl– ions. A practical harvest scheme including applying both PACl and NaOCl to optimize coagulation and maximum yield from Chlorella sp. ESP-6 biomass was discussed.