利用富营养化水体生物膜降解微囊藻毒素研究

Study on Biodegradation of Microcystin Using Biofilms in Eutrophic Water Body

采用一种自行设计的简便生物膜采集装置,自然培养和收集富营养化湖泊——武汉东湖水体中不同深度(20 cm和100 cm)处的生物膜,研究不同水深、相同培养时间以及同一水深、不同培养时间所得生物膜在有氧条件下对微囊藻毒素(MC)的降解过程。结果表明,东湖水体生物膜对MC的降解经历了2～3 d的延滞期,约11 d后可使之降解完全;20 cm水深处培养的生物膜对MC的降解速率快于100 cm水深处培养的生物膜;随着附着生物膜载玻片数量的增多,对MC的降解速率加快;对MC的降解效果与生物膜的培养时间密切相关,按对MC降解速率的快慢排序为:14 d>21 d>7 d;在降解MC的过程中,溶液的pH值持续上升。经分析,生物降解是去除东湖水体中MC的主要途径之一。

A kind of self-designed simple biofilm collection device was used to culture and collect the biofilms in different depths （20 cm and 100 cm water depth） of Donghu Lake of Wuhan City, and the biodegradation of microcystin with the biofilms cultured in different water depths for same times as well as in same water depth for different times under oxygen-containing conditions was studied. The results indicate that the biofilms are capable of degrading microcystin after 11 days with a lag period of 2 to 3 days. The degradation rate with the biofilms cultured in water depth of 20 cm is faster than that in the water depth of 100 cm. Moreover, the degradation rate can be improved as the number of the slides adhering biofilms increases. The degradation effect of microcystin is relative to the culture time of the biofilms, and their degradation rates are as follows： 14 d 〉21 d 〉7 d. During the biodegradation, the pH of solution can rise steadily. The results also show that the biodegradation is one of the main approaches to microcystin removal in Donghu Lake aquatic environment.