Influence of UV stress on lipid content and phenolic compounds concentration of Arthrospira platensis

Phenolic compounds found in Arthrospira platensis has been considered as a source of antioxidant with several therapeutic properties. The aim of this study was to investigate the influence of growth conditions on chemical composition and added value compounds production from A. platensis. To such a purpose, the cyanobacterium has been grown in a tubular photobioreactor for 8 days. UV light was exposed after this period for one, two and three days (3 h/day) and lipid and poliphenol contents were measured. UV stress did not influence the final concentration of the biomass which resulted to be 4.8 g/L. While the lipid content increased 95, 168 and 261% when UV was used for 3, 6 and 9 hours, respectively. Total polyphenols extracted from dry cyanobacterium increased from 5.8 to 15.7 mg/g after three days in control tests. Compared to the control growth, stressed caused by UV exposure for 3, 6 and 9 hours resulted to decrease total polyphenol concentration of 32, 27 and 24%, respectively. The results of this study confirm that UV exposure during the growth of A. platensis can be employed as a crucial operative parameter which positively influenced the lipid contents while decreasing the phenolic concentration.