Isolation and Screening of Microalgae with High-lipid Contents in Shanxi Province

Abstract

This study attempted to choose potential oil-producing microalgae candidates across Shanxi province.Thirty-two strains of microalgae were tested.Among these microalgae,29 strains were isolated from water samples collected from four sites in the Fenghe River and the Salt Lakes Area in Yuncheng.Three strains of microalgae were bought from the Freshwater Algae Culture Collection of the Institute of Hydrobiology.Microalgae from the Shanxi province were isolated and purified by Micro-picking method and Spread-plate method.The biomass of 32 strains of microalgae varied between 48.9-422.2 mg/L,which were determined by dry weight.Chloroform-methanol extraction is a traditional total lipid measuring method and Nile red fluorescence is a new technique used for determining neutral lipids.In this study,Chloroform-methanol extraction and Nile red fluorescent staining were combined to determine lipid contents of the 32 strains of microalgae.The results showed that total lipid content of all strains were in the range of 5.4% DW-30.1% DW,and fluorescence value in unit volume were in the range of 4.1-181.5.High lipid productivity is a key selection criterion of species for biodiesel production.According to the lipid productivity of the microalgae,we screened three strains of microalgae that may be potential oil-producing candidates in Shanxi province.These three strains included NY017(Dunaliella salina),NY023(Nitzschia linearis)and NY025(Nitzschia palea).Their lipid productivities were 3.25 mg · L-1 · d-1,3.03 mg · L-1 · d and 2.11 mg · L-1 · d-1 respectively.