Use of agricultural surpluses for production of biomass by marine microalgae.

The marine microalga Phaeodactylum tricornutum was cultivated in semi-continuous culture under mixotrophic conditions with the soluble fractions of potato, rye and wheat flours that had been naturally fermented, at 2% or 4% (w/v). The rye flour produced the highest microalgal cellular density of 90×10(6) cells.ml(-1) when supplemented with NaNO3 and NaH2PO4. The autotrophic control only gave 57×10(6) cells.ml(-1). The value of agricultural surpluses, such as rye flour, can therefore be increased by its use in the production of valuable, microalgal biomass which is rich in protein, pigments and fatty acids.