The Effects of Physicochemical Factors and Cell Density on Nitrite Transformation in a Lipid-Rich Chlorella.
To understand the effects of physicochemical factors on nitrite transformation by microalgae, a lipid-rich Chlorella with high nitrite tolerance was cultured with 8 mmol/l sodium nitrite as sole nitrogen source under different conditions. The results showed that nitrite transformation was mainly dependent on the metabolic activities of algal cells rather than oxidation of nitrite by dissolved oxygen. Light intensity, temperature, pH, NaHCO3 concentrations, and initial cell densities had significant effects on the rate of nitrite transformation. Single-factor experiments revealed that the optimum conditions for nitrite transformation were light intensity: 300 μmol/m(2); temperature: 30°C; pH: 7-8; NaHCO3 concentration: 2.0 g/l; and initial cell density: 0.15 g/l; and the highest nitrite transformation rate of 1.36 mmol/l/d was achieved. There was a positive correlation between nitrite transformation rate and the growth of Chlorella. The relationship between nitrite transformation rate (mg/l/d) and biomass productivity (g/l/d) could be described by the regression equation y = 61.3x (R(2) = 0.9665), meaning that 61.3 mg N element was assimilated by 1.0 g dry biomass on average, which indicated that the nitrite transformation is a process of consuming nitrite as nitrogen source by Chlorella. The results demonstrated that the Chlorella suspension was able to assimilate nitrite efficiently, which implied the feasibility of using flue gas for mass production of Chlorella without preliminary removal of NOX.
Institute of Bioengineering, Zhengzhou Normal University, Zhengzhou 450044, P.R. China.|Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P.R. China.
Fang
F
Liang
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P.R. China.|University of Chinese Academy of Sciences, Beijing 100049, P.R. China.
Kui
K
Du
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P.R. China.
Xiaobin
X
Wen
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P.R. China.
Liming
L
Luo
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P.R. China.
Yahong
Y
Geng
Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, P.R. China.
Yeguang
Y
Li
D018533:Biomass; D002452:Cell Count; D002708:Chlorella / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism* / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D008027:Light; D009573:Nitrites / Q000378:metabolism*; D017693:Sodium Bicarbonate / Q000378:metabolism; D013696:Temperature
D009573:Nitrites; D017693:Sodium Bicarbonate
Chlorella; NOX; flue gas; nitrite transformation