Production characteristics of Dunaliella salina at two-phase pilot cultivation (Crimea)

Abstract

Productional and biochemical characteristics of green alga Dunaliella salina (Dunal) Teodoresco were studied during pilot cultivation at the south-west of Crimean Peninsula, Russia. Two-phase cultivation was carried out in ponds located in the greenhouse module. In the “green” phase, biomass concentration reached 1.2 g/l, with maximum cell density of 1.69·106 cell/ml and the maximum productivity of 0.08 g/(l·day) (7 g/(m2·day)). Twofold culture dilution was applied for carotenogenesis induction. The maximum cell density in the “red” phase was 0.84·106 cell/ml, while biomass reached 0.95 g/l. Mean net carotenoid accumulation rate at the second stage (1-6 day) was 0.65 mg/(l·day). Carotenoids content in culture doubled compared to initial values and reached about 20 mg/l or 800 mg/m2. Carotenoids/chlorophyll a ratio of 11.6 was observed by the end of the “red” phase. Night biomass loss was higher in the “red” phase (up to 9.5% of biomass) compared to the “green” phase (up to 5.6%). Optimal duration of both the first and the second cultivation stages was found to be 10-12 days for the studied weather conditions, which enables production of 3 g of carotenoids from 1 m2 (100 l) of starter culture. In conclusion, Crimea is a prospective region for D. salina algobiotechnology.