Continuous cultivation of Dunaliella salina in photobioreactor for the production of β-carotene

A helix tube photobioreactor with a volume of 10 L was designed and manufactured. The facade of the reactor was designed as three-layer frame. The illumination helixes units were 16, illumination area volume was 1.5 L, illuminate specific area was 95 m−1. A marine micro-alga Dunaliella salina was used as a model organism in this study. Results showed that the optimum inoculum concentration was OD630 = 0.15 and the optimum circulation rate of culture fluid was 630 mL/h for the bioreactor. In continuous cultivation, in order to determine the optimum collection of alga solution for the highest yield of β-carotene, three different alga solution collection and addition fresh culture medium volumes were applied: 0.8, 1.5, 2.0 L/day. The biomass and extraction of β-carotene were determined in different cultivation periods. The result suggested that the optimum daily harvest of alga solution was 1.5 L/day for the cultivation of D. salina to obtain the highest production of β-carotene.