微藻在不同氨氮条件下固定CO2耦合净化废水实验

为探究小球藻同步固定CO₂、净化废水及生产蛋白质的潜力,实验研究不同氨氮浓度(30,60,90 mg/L NH₄Cl)和CO₂体积分数(0.038%和10%)对小球藻(Chlorella vulgaris)生长、固碳、氮磷营养盐去除及蛋白质生产的影响,并将Logistic方程与改进的Monod方程相结合,描述小球藻比生长速率与氮、磷营养盐的关系。结果表明:10% CO₂组生物量(380.16~499.52 mg/L)是0.038% CO₂组生物量(44.73~120.00 mg/L)的3.54~8.30倍,同时,10% CO₂组中氨氮和磷酸盐消耗速率明显高于0.038% CO₂组。小球藻比生长速率、固碳速率、蛋白质含量均与生物量呈正相关(R2≥0.83,P<0.05),且在10% CO₂和60 mg/L NH₄Cl条件下获得最大值,分别为0.21 d-1、42.62 mg/(L·d)和228.43 mg/L。此外,拟合结果显示Logistic方程与改进的Monod方程联合应用可较好地描述小球藻的生长过程(R2=0.39~0.96),且10% CO₂条件下的营养盐更易被小球藻吸收。实验结果可为微藻同步固定CO₂、净化废水及副产物(如蛋白质)生产的应用提供理论参考。

EXPERIMENTAL STUDY ON CO2 FIXATION COUPLED WITH WASTEWATER PURIFICATION BY CHLORELLA VULGARIS UNDER DIFFERENT AMMONIUM CONCENTRATIONS

To explore the potential of Chlorella vulgaris(C. vulgaris) in fixing CO₂, purifying wastewater and producing protein simultaneously, the effects of different ammonium concentrations(30 mg/L, 60 mg/L, 90 mg/L NH₄Cl) and CO₂ concentrations(0.038% and 10%) on the growth, CO₂ fixation, nutrients removal and protein production of C. vulgaris were studied. The combination of Logistic function and the modified Monod function was also used to describe the relationship between C. vulgaris specific growth rate and concentration of ammonium(NH+₄-N) and phosphate(PO3-₄-P), respectively.Resultsshowed that the biomass of 10% CO₂ group(380.16~499.52 mg/L) was 3.54~8.30 times that of 0.038% CO₂ group(44.73~120.00 mg/L). Meanwhile, the consumption rates of ammonium and phosphate in the 10% CO₂ group were significantly higher than those in the 0.038% CO₂ group. Correlation analysis showed that specific growth rate, carbon fixation rate, protein were all positively correlated with C. vulgaris biomass(R2>0.86, P<0.05). With 10% CO₂ and 60 mg/L NH₄Cl, the maximum values of specific growth rate, carbon fixation rate, and protein were 0.21 d-1, 42.62 mg/(L·d), and 228.43 mg/L, respectively. In addition, the fitting results indicated that the combination of Logistic function and the modified Monod function could well describe C. vulgaris growth(correlation coefficient R2 is 0.39~0.96), and nutrients were more easily utilized by C. vulgaris at 10% CO₂. This experiment could provide a theoretical reference for fixing CO₂, purifying wastewater and producing protein simultaneously by microalgae.