초록
<P><B>Abstract</B></P> <P>With the aim to optimize the production of exopolysaccharide (EPS) by <I>Porphyridium marinum</I>, cultures in photobioreactors were conducted on a modified Provasoli medium (P) and compared to a new medium (Pm) with an elemental composition of N<SUB>0.0205</SUB>S<SUB>0.0597</SUB>P<SUB>0.005</SUB>. Cultivation on this medium allowed the increase of EPS concentration up to 2.5gL<SUP>−1</SUP>, without modification of the EPS productivity (0.096gL<SUP>−1</SUP>) and EPS structure. In a second time, photosynthetic activity of the strain was monitored as a function of irradiance and temperature, allowing improvement of kinetic parameters of growth and EPS production. A semi-continuous culture, carried out with the Pm medium, an optimal irradiance and temperature of respectively 360μmolphotonsm<SUP>−2</SUP> s<SUP>−1</SUP> and 28°C led to an EPS process productivity of 0.031gh<SUP>−1</SUP> instead of 0.020gh<SUP>−1</SUP> in batch culture.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Porphyridium marinum</I> is a source of sulfated exopolysaccharides. </LI> <LI> Stoechiometry of culture medium influenced the EPS production. </LI> <LI> Optimal conditions of irradiance, pH and temperature optimized EPS production. </LI> <LI> Semi-continuous culture increased EPS productivity. </LI> </UL> </P>