Isolation of a novel strain of Monoraphidium sp. and characterization of its potential application as biodiesel feedstock

A novel green microalgae strain from Lake Fuxian has been isolated and identified as a potential feedstock for biodiesel production. The novel strain was named Monoraphidium sp. FXY-10 based on its morphological and genomic characterization. The lipid productivities, fatty acid profiles, and microalgae recovery efficiency (ηa) of FXY-10 were investigated and compared under autotrophic and heterotrophic conditions. FXY-10 under autotrophic conditions exhibited a higher cellular lipid content (56.8%) than those under heterotrophic conditions (37.56%). However, FXY-10 growing under heterotrophic conditions exhibited more than 20-fold increase in lipid productivity compared with that under autotrophic conditions (148.74 mg L−1 d−1 versus 6.88 mg L−1 d−1). Moreover, higher saturated and monounsaturated fatty acids (77.5%) of FXY-10 was obtained under heterotrophic culture conditions, suggesting its potential as a biodiesel feedstock. Gravity sedimentation was proposed as the harvesting biomass method based on the 97.9% microalgae recovery efficiency of heterotrophic cells after settling for 24 h.