微藻对壬基酚的响应及去除能效研究

分离筛选11种微藻开展微藻对NP暴露的响应特征和去除能效研究。NP对叶绿素a含量的96 h半抑制效应浓度(EC50)介于0.60~3.33 mg·L~(-1)之间,EC50由小到大依次为:短棘盘星藻羊角月牙藻小球藻衣藻斜生栅藻肥壮蹄形藻卷曲纤维藻二尾栅藻惠氏微囊藻四尾栅藻蛋白核小球藻。除斜生栅藻、羊角月牙藻、肥壮蹄形藻、卷曲纤维藻之外,微藻的生长速率与EC50呈显著的正相关关系。EC50与细胞粒径、表面积以及体积总体上呈负相关关系,与微藻对NP的最大去除速率和半饱和常数呈正相关关系。NP的藻类去除过程符合一级反应动力学方程,且NP的半衰期与微藻起始总表面积呈显著的负相关关系。NP对微藻群落的影响与其浓度相关,其选择性干扰效应主要与微藻耐受性相关。NP耐受性高的种类多表现出高生长速率和去除能力。

Bioremoval of Nonylphenol and Variable Responses of Freshwater Algae under Nonylphenol Exposure

The effects of nonylphenol (NP) on growth, chlorophyll a content of eleven freshwater algae and their bioremoval ability on NP were compared. Acute toxic of NP was conducted with ten concentrations of NP (0.10, 0.16, 0.25, 0.40, 0.63, 1.00, 1.59, 2.52, 4.00, 6.30, 10.06 mg?L￣1), where a final acetone concentration of 0.1% (v/v) was set as control. The NP bioremoval in eleven algal cultures was determined during incubation with 100, 200, 400, 600, 800, 1 000μg?L￣1 of NP in BG￣11 medium after exposure for 1 h, while the changes of NP (1 mg?L￣1 ) in algal cultures were determined at 0 min, 10 min, 30 min, 1 h, 6 h, 12 h and 24 h. The half inhibitory effect con￣centrations (EC50 ) of NP on Chl.a ranged from 0.6 to 3.33 mg?L￣1 after being cultured for 96 h. The EC50 values suggested that the tolerance of algae to NP increased according to the following order:Pediastrum boryanum, Sele￣nastrum capricornutum, Chlorella sp., Chlamydomonas sp., Scenedesmus obliquus, Kirchneriella obesa, Ankistro￣desmusconvolutus, Scenedesmusbicauda, Microcystiswesenbergii, Scenedesmusquadricandaand Chlorellapyre￣noidosa.A positive correlation was detected between algal growth rate and EC50 values, except for S.obliquus, S. capricornutum, K.obesa and A. convolutus. In addition, negative correlations were detected between EC50 values and cell size, surface area and volume, respectively. Removal rate of NP in all algal species were higher than 90%at 24 h, and a positive correlation was detected between NP removal rate and the total cell surface areas. The algal removal of NP (1 mg?L￣1) followed the first￣order kinetics equation. A negative correlation was observed between the half￣life of NP and total algal surface area. Removal rates of NP under different initial NP concentrations were well fitted with Michaelis￣Menten equation. The maximum removal rates of NP ranged from 9.94 to 91 μg?(mg?h)￣1, while half saturated constant ranged from 10.38 to 79.43μg. Positive correlation were detected between EC50 values and the maximum removal rates of NP, EC50 values and half saturated constants, respectively. Effects of NP on growth of algae and structure of community were dependent on the NP concentration. Variation of community was influenced by the tolerance of NP among tested algal species. Algal species with higher tolerance of NP showed higher growth rates and higher bioaccumulation of NP.