Department of Environmental Science and Engineering, Xiangtan University, Xiangtan 411105, PR China.
Aquat Toxicol. 2013 Aug 15;138-139:81-7. doi: 10.1016/j.aquatox.2013.04.010. Epub 2013 Apr 29.
The removal of nutrients by algae is regarded as a vital process in wastewater treatment, however algal cell activity can be inhibited by some toxic chemicals during the biological process. This study investigated the uptake of ammonia nitrogen (NH₄⁺) and total phosphorus (TP) by a green alga (Chlorella vulgaris) and algal cell responses under the stress of cetyltrimethyl ammonium bromide (CTAB), a representative for quaternary ammonium compounds (QACs, cationic surfactants). When the concentration of CTAB increased from 0 to 0.6 mg/L, the uptake efficiencies of NH₄⁺ and TP decreased from 88% to 18% and from 96% to 15%, respectively. Algal cell responses showed a decline in photosynthesis activity as indicated by the increase of chlorophyll autofluorescence from 2.9 a.u. to 25.3 a.u.; and a decrease of cell viability from 88% to 51%; and also a drop in esterase activity as indicated by the decrease in fluorescence of fluorescein diacetate stained cells from 71.5 a.u. to 4.7 a.u. Additionally, a transcription and translation response was confirmed by an enhancement of PO peak and amide II peak in algal cellular macromolecular composition stimulated by CTAB. The results suggest that QACs in wastewater may inhibit nutrient uptake by algae significantly through declining algal cell activities.
藻类去除营养物质被认为是废水处理中的一个重要过程，然而在生物过程中，一些有毒化学物质会抑制藻类细胞的活性。本研究调查了绿藻（普通小球藻）对氨氮（NH₄⁺）和总磷（TP）的吸收，以及在十六烷基三甲基溴化铵（CTAB）的胁迫下藻类细胞的反应，CTAB 是季铵化合物（QACs，阳离子表面活性剂）的代表。当 CTAB 浓度从 0 增加到 0.6mg/L 时，NH₄⁺和 TP 的吸收效率分别从 88%降至 18%和从 96%降至 15%。藻类细胞的反应表现为光合作用活性下降，叶绿素自发荧光从 2.9a.u.增加到 25.3a.u.；细胞活力从 88%降至 51%；酯酶活性也下降，荧光素二乙酸酯染色细胞的荧光从 71.5a.u.降至 4.7a.u.。此外，CTAB 刺激藻类细胞大分子组成中 PO 峰和酰胺 II 峰的增强，证实了转录和翻译反应。结果表明，废水中的 QACs 可能通过降低藻类细胞的活性，显著抑制藻类对营养物质的吸收。
