Isolation and identification of Choricystis minor Fott and mass cultivation for oil production

The use of wastewater-grown algae for biofuel production is economical and eco-friendly. In the present study, an algal strain was isolated from the wastewater of a local dairy farm. On the basis of the morphology, ultrastructure, and 18S rRNA gene sequences, the specimen was identified to be conspecific with Choricystis minor Fott, which is a newly reported species in China. The C. minor cells accumulated predominantly neutral lipids that accounted for 60.82% of total lipids with 35.61% being triacylglycerol. Enlarged oil droplets were observed under nitrogen-depleted condition. C. minor was further cultivated outdoors on a larger scale, in which we employed both flat-plate and tubular photobioreactors (PBRs). The algae quickly adapted to the outdoor conditions and exhibited good growth performance (biomass and lipid productivities were 162.86 and 36 mg L− 1 day− 1 in flat-plate PBRs). Taken together, these results support the finding that C. minor is a promising source of low-cost, high-quality oil for biofuel production.