不同C/N下硫对斜生栅藻生长与油脂积累的调控

Regulation of sulfur on growth and lipid accumulation of Scenedesmus obliquus under different C/N ratio

为探究不同C/N污水下下硫对微藻生长、水体净化与油脂积累的调控作用,以斜生栅藻为研究对象,通过改变NH_(4)^(+)-N浓度配制了4种不同C/N的实验用水,对比研究了斜生栅藻在无硫和含硫条件下经5 d培养后的生长、碳氮利用与油脂合成情况。结果表明,外源硫添加可有效促进微藻的生长,当C/N为15时,藻细胞密度达到最大,为1.23×10^(7)cells·mL^(−1),较无硫条件提高了90%;同时,外源硫也有助于提升藻细胞对碳氮的利用效率,微藻对有机物的利用效率随着C/N的降低而升高,并在C/N为7.5时最大,为80.33%,较无硫条件提升了63%;当C/N为7.5时NH_(4)^(+)-N去除率为73.6%,较无硫条件提升了149%,其余实验组别NH_(4)^(+)-N去除率均达100%;此外,在含硫条件下,油脂产率和油脂含量均随着C/N升高而降低,均在C/N为7.5时达到最大,油脂产率为5.04 mg·(L·d)^(−1),相较于无硫条件提升了50.51%,油脂含量为15.4%,较无硫条件下降了33.3%,表明硫加入可有效提升油脂产率但不利于油脂积累,在低C/N条件下促进作用更强。综合来看,当C/N在7.5—15时,外源硫加入取得的综合效益最佳。通过探究微藻生长、碳氮利用、油脂积累的适宜条件,可为微藻的精细化培养提供参考。

To explore the regulating effect of sulfur on the growth and lipid accumulation of Scenedesmus obliquus under different C/N ratio conditions,taked Scenedesmus obliquus as the research object,set 4 kinds of experimental water with different C/N ratios by changing the concentration of ammonia nitrogen,and comparatively studied the growth and lipid synthesis of microalgae after 5 days of culture under both sulfur-free and sulfur-containing conditions.The results showed that the addition of exogenous sulfur can effectively promote the growth of microalgae.When C/N ratio was 15,the density of microalgae reached the maximum,which was 1.23×10^(7)cells·mL^(−1),it was 90%higher than the sulfur-free condition.Additional sulfur also helped to improve the carbon and nitrogen utilization efficiency of microalgae.The utilization efficiency of organic matter by microalgae increased with the decrease of carbon to nitrogen ratio,when C/N was 7.5,it reached 80.33%,which was 63%higher than that of sulfur-free conditions,while the ammonia nitrogen removal efficiency was 73.6%,which was 149%higher than the sulfur-free condition,and the removal efficiency of the remaining experimental groups reached 100%.In addition,under the sulfur-containing condition,the lipid yield and lipid content both decreased with the increase of carbon to nitrogen ratio.When C/N ratio was 7.5,the lipid yield was highest,which was 5.04 mg·(L·d)^(−1),it was 50.51%higher than that of sulfur-free conditions.When the C/N ratio was 7.5,the lipid content was 15.4%,which was 33.3%lower than the sulfur-free condition,indicating that sulfur addition can effectively increase the lipid yield but was not conducive to the accumulation of lipid,and exogenous sulfur had a stronger promoting effect under low carbon to nitrogen ratio conditions.In summary,when the C/N ratio was between 7.5 and 15,the overall benefits were relatively best.By exploring the appropriate conditions for microalgae growth,carbon and nitrogen utilization,and lipid accumulation,This research can provide references for the refined cultivation of microalgae.