Growth-promoting effects of alginate-derived oligosaccharides on marine microalgae

This study evaluated the effects of different doses of alginate-derived oligosaccharides (ADOs; 5 to 100 mg L-1) on the growth of nine marine microalgae in batch culture. The growth-promoting effects of ADOs on Phaeodactylum tricornutum and Chlorella sp. were the most obvious. Particularly, the specific growth rate of P. tricornutum increased from 0.45 day(-1) (without ADOs added) to 0.88 day(-1) (100 mg L-1 ADOs added). The specific growth rate of Chlorella sp. increased from 0.25 to 0.75 day(-1). ADO treatment did not significantly change the photosynthetic electron transport activity of Chlorella sp. but increased that of P. tricornutum. Therefore, ADOs can be used as an organic carbon source by Chlorella sp. through mixotrophic assimilation and as a photosynthetic regulator to promote the growth of P. tricornutum. Our study thus provides a novel strategy for promoting the growth of marine microalgae.