不同氮源对2种微藻生长及总脂含量的影响

采用一次培养的方式研究硝态氮（NaNO3）、氨态氮（NH4Cl）、有机氮（尿素）及硝铵混合氮（NH4NO3）（氮浓度17.6 mmol.L-1）对新分离的两株热带淡水微藻——网状空星藻Coelastrum reticulatum及栅藻Scenedesums sp.生长情况及总脂含量的影响。结果表明,2株微藻在不同氮源影响下生长状况不同,并且造成最终的干质量、总脂含量也有较为明显的差异。2种藻添加NaNO3和NH4Cl情况下分别获得了最高的生物量（（0.72±0.08）g.L-1和（0.80±0.03）g.L-1）和最高总脂含量（（38.35±1.32）%和（30.24±3.13）%）。最终二者在添加NaNO3的情况下单位体积总脂产量最高,分别为199.26 mg.L-1和190.76 mg.L-1,均可作为生物柴油的良好来源。

Effects of nitrogen sources on growth and total lipid contents of Coelastrum re- ticulatum and Scenedesums sp.

Microalgal lipids are regarded as the feedstock for sustainable biodiesel production because microalgae have much higher growth rates and photosynthetic efficiencies than conventional terrestrial plants. However, relatively high production costs have been one of the major obstacles impeding their commercial production. While the lipid yield determines the costs of the cultivation process, biomass concentration and lipid content affect significantly the downstream processing costs. Nitrogen sources in the culture media can regulate a degree of biomass/cellular lipid accumulations. In this work, effects of different nitrogen sources, i.e. nitrate, ammonium and urea （17.6 mmol.L-1） on the growth and total lipid contents of Coelastrum reticulatum and Scenedesums sp., were studied. The results showed clearly that there was a significant difference on nitrogen use efficiency and lipid content of the two microalgal species. The relationship among cell growth, lipid content, and cell pigments content were discussed. It was found that maximum biomass （（0.72±0.08） g.L 1 and （0.80±0.03） g.L-1, respectively） and lipid content （（38.35± 1.32%） dw and （30.24±3.13）% dw, respectively） was obtained as C. reticulatum and S.sp. were cultured in BGll medium containing NaNO3 and NH4Cl. Lipid yield of C. reticulatum and S. sp. cultured in BG11 medium containing NaNO3 （199.26 mg.L-1 and 190.76 mg.L-1） make them potential source for biodiesel production in tropical regions.