Fresh water Chlorella pyrenoidosa XJ01 strain and application thereof in fixing CO2 and producing microalga grease

The invention discloses a fresh water Chlorella pyrenoidosa XJ01 strain and application thereof in fixing CO2 and producing microalga grease. The collection number of the Chlorella strain is CCTCC NO: M 2013103. The Chlorella strain disclosed by the invention can efficiently fix 0.03-20% of CO2, wherein the CO2 fixation efficiency is 140-376 mg/L/d, the biomass (dry weight) concentration is 760-2460 mg/L, and the grease content is 23.7-34.5%; and the grease fatty acid is mainly composed of C16 and C18 short-chain fatty acids, and is suitable for producing bio-diesel. Compared with the reported microalgae, the Chlorella strain disclosed by the invention has higher CO2 fixation efficiency and biomass yield, and can obtain high-yield microalga grease by selecting proper culture conditions, thereby greatly lowering the microalga grease production cost, and providing an excellent production alga strain for preparing bio-diesel from CO2 and microalga grease in an efficient fixing environment.