Optimization of Cryopreservation Process Using Response Surface Methodology for Chlorella saccharophila and Chlorella zofingiensis

Abstract

The preservation of microalgae in a stable state is a fundamental requirement in pharmaceutical,agricultural, environmental sciences and different industries. Cryopreservation is widely stabilized forachieving long-term storage and has been applied to an increasingly diverse range of microalgae and cellcultures. The continuous storage of actively growing microalgae strains by routine serial subculture isrelatively time-consuming and this technique has possible contamination risks. In this study, theoptimization of cryopreservation process was carried out for two different Chlorella strains using responsesurface methodology (RSM) with three factors (cryoprotectant concentration, incubation time andcryopreservation time) including 19 runs. The optimal cell viability of C. zofingiensis was found at thedimethyl sulfoxide (DMSO) concentration of 12.89% at the incubation time of 8.14 min and with thecryopreservation time of 93.45 day, while C. saccharophila was found at the DMSO concentration of 12.86% at the incubation time of 7.99 min and at cryopreservation time of 95.17 day.