Screening and Characterization of Oleaginous Microalgal Species from Northern Xinjiang

A total of 646 strains, including green algae and diatoms, were isolated from 220 samples to screen microalgae with high lipid productivity (LP). The samples were obtained from nine habitats in Northern Xinjiang, China in June 2013. This study initially identified eight lipidrich strains, namely, Desmodesmus intermedius XJ-498, D. intermedius XJ-145, D. intermedius XJ- 99, Monoraphidium pusillum XJ-489, M. dybowskii XJ-435, M. dybowskii XJ-151, Mychonastes homosphaera XJ-488, and Podohedriella falcata XJ-176, based on 18S rDNA sequencing. The strains were cultured in a photobioreactor for the same period. Results showed that the specific growth rate (day(-1)) of M. pusillum XJ-489 was the highest (1.14 ± 0.06), and the biomass concentration (g/l) of D. intermedius XJ-99 was the highest (2.84 ± 0.3). Futhermore, the lipid content (%) of M. dybowskii XJ-151 was the highest (33.5 ± 4.38), and the lipid productivity (mg l(-1) day(-1)) of My. homosphaera XJ-488 was the highest (86.41 ± 9.04). C16 to C18 accounted for 86% to 98% of the total lipid, and the biodiesel qualities of the selected algae corresponded to international standards. This study suggests that My. homosphaera XJ-488, D. intermedius XJ-99, and M. dybowskii XJ-151 are the most potential strains for biodiesel production among all the isolated strains.