Characterization of the new microalgal strains, Oogamochlamys spp., and their potential for biofuel production

Isolation of novel lipid-producing microalgae that can easily grow under photoautotrophic conditions is promising for biofuel production. In this study, we isolated indigenous microalgal strains and screened their lipid-producing activity. Freshwater supplemented with several nutrients was used for the cultivation of indigenous microalgae to minimize enrichment bias. Photoautotrophic cultivation in microplates resulted in 388 unialgal strains, and 59 strains of them were stained by Nile Red. Phylogenetic studies based on 18S ribosomal DNA suggested that these belonged to 6 genera including Chlorella, Scenedesmus, Monoraphidium, Coccomyxa, Macrochloris, and Oogamochlamys. Considering the cellular lipid content and biomass yield under photoautotrophic conditions, Oogamochlamys spp. IKE31 and IKE32 show promise for biofuel production. These strains are rich in unsaturated fatty acids, which implies that they may also be useful as feed for animals and aquaculture species. Lipid productivity of the strains was dramatically increased by phosphate limitation, which may be beneficial for industrial applications.