Enhanced Biomass Productivity and β-cryptoxanthin Content of Chlorococcum sp. through Optimization Via Central Composite Design (CCD)

β-cryptoxanthin is one of the most commercially valuable carotenoids, which is rare in nature and costly to synthesize. Microalgae is a promising alternative and renewable source for β-cryptoxanthin production. This study aimed to optimize the cultivation of the microalgae, Chlorococcum sp. TISTR 8266, in BG–11 medium, to achieve the highest yield of β-cryptoxanthin. Therefore, central composite design (CCD) was employed to optimize the addition of organic carbon and nitrogen sources under mixotrophic and heterotrophic conditions combined with aeration and agitation. The results showed that under the mixotrophic conditions, the BG–11 medium with 1.6 g/L of glucose and 0.16 g/L of urea enhanced the biomass of Chlorococcum sp. to 4.90 ± 0.14 and 4.85 ± 0.07 g/L with aeration and agitation, respectively. Furthermore, under the optimized conditions, β-cryptoxanthin, β-carotene, and lutein content increased to 4.02 ± 0.49, 4.50 ± 0.71, and 12.76 ± 0.26 mg/g dry cell weight (DCW), respectively. In contrast, β-carotene presented the highest content of 5.05 ± 0.52 mg/g DCW for the control (non-modified BG–11 medium). Hence, the cultivation time was 50% decreased (from 14 days to 7 days) while the biomass increased from 2.50 g/L to 4.9 g/L and β-cryptoxanthin content increased from 0.064 mg/g cell dry weight to 4.02 mg/g cell dry weight when compared to the control conditions in our previous study. Overall, these findings offer new and economically feasible perspectives for β-cryptoxanthin production by the selected microalgal strain.