Simultaneous enhancement on renewable bioactive compounds from Porphyridium cruentum via a novel two-stage cultivation

Porphyridium cruentum is a versatile cell factory to produce various bioactive and vital substances for food, feed, cosmetics and pharmaceuticals. In this study, a novel two-stage cultivation was the first time to establish for microalgal growth and bioactive compounds production by regulating light-emitting diodes wavelengths using marine microalga Porphyridium cruentum. Firstly, the best light light-emitting diodes wavelength(s) was/were optimized for microalgal growth, and B-phycoerythrin, polyunsaturated fatty acids and exopolysaccharides production by microalga. Results showed that green wavelength significantly enhanced microalgal cell growth (2.93 g/L), and B-phycoerythrin (51.65 mg/g biomass) and exopolysaccharides (255.62 mg/L) synthesis, while white wavelength promoted total fatty acids (7.51%) and polyunsaturated fatty acids (48.21 mg/g biomass) accumulation. Then, a two-stage cultivation was developed and re-evaluated. It was found that microalga grown in the two-stage cultivation (12 days for green wavelength and then 6 days for white wavelength) had similar biomass and achieved higher bioactive substances contents compared with the one-stage cultivation with green wavelength. The developed two-stage cultivation could address the issue about the decrease in B-phycoerythrin content by the one-stage cultivation. Overall, this two-stage cultivation was an efficient strategy for microalgal growth and renewable bioactive substances production by P. cruentum.

Automated summary

A novel two-stage cultivation method was developed for Porphyridium cruentum microalgae using different wavelengths of light-emitting diodes to optimize growth and bioactive substances production. Green wavelength enhanced cell growth and bioactive compounds synthesis, while white wavelength promoted fatty acid accumulation. Compared to one-stage cultivation, the two-stage cultivation showed higher efficiency in microalgal growth and productivity.