研究了不同浓度NaNO3对CO2间断通气培养与NaHCO3添加培养条件下发状念珠蓝细菌生长、光合速率、胞外多糖积累、蛋白质含量、色素含量、磷酸根与硝酸根消耗、细胞固碳率以及光合效率的影响。结果表明，在CO2通气条件下添加NaNO3能够显著促进发状念珠蓝细菌的生长。2.0 g/L的NaNO3为最佳浓度，干重达到1.56 g/L，为对照的2.29倍，呼吸与净光合速率达到最大。当NaNO3浓度达到2.5 g/L时，藻细胞干重停止增加。细胞叶绿素含量随着NaNO3浓度的增加而增加。硝酸钠添加组胞外多糖的含量相比不添加组均下降，但添加组的多糖含量随NaNO3浓度的增加而增加。细胞蛋白质含量随NaNO3浓度的增加而增加，在2.0 g/L时达到最高。与生物量的增加相对应，细胞对两种盐分的利用率在NaNO3为2.0 g/L时达到最大。CO2通气培养时添加NaHCO3可进一步促进细胞的生长。在两种碳源同时存在时，NaNO3对细胞的生长促进作用与单一碳源存在培养时类似。

In this study, the effect of different concentrations of NaNO3 on the growth, photosynthetic rate, exopolysaccharide accumulation, protein and pigment content, phosphate and nitrate consumption, cell sequestration rate, and photosynthetic efficiency of Nostoc flagelliforme, incubated with intermittent CO2 flow, was investigated. The results showed that addition ofNaNO3with intermittent flow of CO2 could significantly promote the growth of N. flagelliforme. The optimal NaNO3 concentration for biomass production was 2 g/Land the dry weight could reach up to 1.56 g/L, which was 2.29 times as much as that for the control. Maximum respiration as well as net photosynthetic rate was achieved. However, when the concentration of NaNO3 was increased to 2.5 g/L, the biomass no longer increased. Cell chlorophyll content increased with increasing NaNO3 concentration. However, in the NaNO3 group, exopolysaccharide content decreased compared with the groups without NaNO3, and polysaccharide content increased with increasing NaNO3 concentration. The protein content of N. flagelliforme cells increased with increasing NaNO3 concentration and reached maximum value at 2.0 g/L. Corresponding to the increase in biomass, the highest utilization rate of nitrite and phosphate was achieved when the concentration of NaNO3 was 2.0 g/L. With intermittent CO2 flow incubation, addition of NaHCO3 could further promote cellular growth. When two carbon sources co-existed, the growth-promoting effect of NaNO3on cells was similar to that when there was only one carbon source.

天津科技大学自然科学研究基金（20130108）