Optimization of the growth and marennine production by the diatom Haslea ostrearia in photobioreactor

Submerged membrane photobioreactor for the cultivation of Haslea ostrearia and the continuous extraction of extracellular marennine

Haslea ostrearia is a marine diatom known to produce and excrete the marenine blue pigment. Its controlled, continuous and intensified cultivation remains a challenge. Thus, a submerged membrane photobioreactor (MPBR) was implemented in order to simultaneously and continuously cultivate H. ostrearia and extract marennine. The MPBR was compared with a similar air-lift photobioreactor (without membrane), both working at a dilution rate equal to 0.1, 0.3 and 0.5 d^-1. Contrary to the air-lift photobioreactor, the MPBR successfully operated at high dilution rate without biomass washout. The MPBR allowed continuously recovering marennine and reaching high cell density (555 ± 25 × 10⁶ cells L^-1 at D = 0.1 d^-1), marennine concentration (36.00 ± 0.02 mg L^-1 at D = 0.1 d^-1) and marenine productivity (7.20 ± 0.01 mg L^-1 d^-1 at D = 0.5 d^-1).