Induction of β, ε-carotene-3, 3′-diol (lutein) production in green algae Chlorella salina with airlift photobioreactor: interaction of different aeration and light-related strategies

Abstract

The impact and interaction of light irradiance strength (light intensities), lighting cycle (photoperiod), and aeration rate on biomass concentration and lutein production efficacy of the microalga Chlorella salina in a closed laboratory-scale airlift photobioreactor were investigated via the response surface method. Among the factors assessed, light intensity and aeration rate had significant influence on cell concentration, though a concurrent increment in light intensity noticeably decreased the lutein content. All the parameters were observed to be statistically significant. Best operating conditions for the growth of alga was evaluated to be as follows: light intensity, 200 μmol m−2 s−1; photoperiod, 12:12 h L D; and the aeration rate, 3 lpm. These conditions could substantially enhance the microalgal growth rate (0.82 day−1) and biomass production (665.89 mg). Specific lutein productivity and a recovery of 9.73 mg/L/day were achieved at a day light cycle of 16 h. According to the results of the experimental design, the optimum conditions led to a twofold increase in biomass and lutein productivity compared with unoptimized condition.