Optimal cultivation towards enhanced biomass and floridean starch production by Porphyridium marinum

Optimal conditions for maximal biomass and starch production by the marine red microalgae Porphyridium marinum were investigated. Box-Behnken Design was used to model the effect of light intensity, NaNO3 concentration and salinity on the growth of microalgae but also on their starch and protein contents. These three factors increased biomass production by 13.6% in optimized conditions. A maximum starch production (140.21 mu g.mL(-1)), 30.6% higher than that of the control, was attained at a light intensity of 100 mu mol photons.m(-2).s(-1), a NaNO3 concentration of 1 g.L-1 and a NaCl concentration of 20 g.L-1. FT-IR spectroscopy was used to estimate the biochemical composition (carbohydrate accumulation) of P. marinum and revealed significant changes (P < 0.05) depending on culture conditions. FT-IR analysis highlighted also that the culture conditions leading to highest starch production by P. marinum corresponded to lowest sulfated polysaccharide and protein contents. (C) 2019 Elsevier B.V. All rights reserved.