Enhanced production of astaxanthin by Chromochloris zofingiensis in a microplate-based culture system under high light irradiation

Abstract

The green microalga Chromochloris zofingiensis is a promising producer of natural astaxanthin. In the present study, C. zofingiensis was first cultivated in shake flasks under low light irradiation and then subjected to continuous high light irradiation, which effectively promoted astaxanthin production. In addition, a microplate-based culture system in concert with high light irradiation from blue light and white light above 150μmolm^-2s^-1 was constructed and applied to improve astaxanthin production. Blue light exerted more positive influences on astaxanthin accumulation, but when the light intensity was increased to 300μmolm^-2s^-1, astaxanthin biosynthesis was substantially inhibited. Conversely, in a nitrogen-deprived culture under white light, the highest astaxanthin content for C. zofingiensis, 7.1mg/g, was obtained. The highest astaxanthin yield achieved was 38.9mg/L in a culture with 0.1g/L nitrate under the same culture conditions. This study demonstrates that C. zofingiensis has great potential for natural astaxanthin production.

Keywords: Astaxanthin; Blue light; Chromochloris zofingiensis; Microplate-based culture; White light.