蓝藻次生代谢产物所导致的嗅味问题已成为饮用水的主要水质问题之一,然而不同种属蓝藻的产嗅特征往往差别明显.本研究将从洋河水库中分离得到的可高产土臭素(geosmin)的螺旋鱼腥藻(Anabaena sp.)进行扩大化培养,通过测定不同营养源条件下的生物量及土臭素等各项指标的变化,探讨了不同营养盐条件对该螺旋鱼腥藻生长及产嗅特征的影响.结果表明,不同氮源及磷源条件下,产生的土臭素主要分布在藻细胞内,胞外含量基本在0.2%~9.6%的范围内;与氨氮相比,硝氮更能促进螺旋鱼腥藻的生长,最高产嗅量是氨氮条件下的1.4倍;氨氮浓度0.5 mg/L条件下,相应藻细胞及产嗅量均达到最高值,分别为3.8×104cells.mL-1和1.1×104ng.L-1,而硝氮浓度在2.0 mg/L条件下达到最高值,分别为6.6×104cells.mL-1和1.3×104ng.L-1;与氮源条件相比,磷源浓度在0.12 mg/L条件下才能够显著促进藻细胞的生长,是螺旋鱼腥藻生长的限制性营养源.洋河水库中营养盐的浓度已具备螺旋鱼腥藻生长所需的营养条件,为抑制该水库的蓝藻水华及嗅味问题,应有效削减水库中营养盐尤其是磷的含量.
The occurrence of taste and odors,produced by secondary metabolites of cyanobacteria,has been one of the major water quality problems in drinking water.However,the odorous compounds produced by cyanobacteria usually differ significantly with different species.One cyanobacterium isolated from Yanghe reservoir was identified as Anabaena sp.,which can produce high level of geosmin consistently during laboratory culture.By culture expanding experiments,the algal growth and geosmin production characteristics of the Anabaena sp.were studied on different conditions of nitrogen and phosphorus sources.The results indicated that geosmin mainly remained in the intracellular algal cells regardless of the nutrient sources,and the extracellular content was only in the range of 0.2%-9.6%.Compared with ammonia nitrogen conditions,the growth of Anabaena sp.in nitrate nitrogen conditions was much higher,with a 1.4-fold variation in geosmin production.While ammonia nitrogen concentration was 0.5 mg/L,the algal biomass and geosmin production achieved the highest level of 3.8×104cells·mL-1 and 1.1×104 ng·L-1,respectively.When the nitrate nitrogen concentration was 2.0 mg/L,the algal biomass and geosmin production achieved the highest level of 6.6×104 cells·mL-1 and 1.3×104ng·L-1,respectively.Compared with nitrogen sources,the growth of Anabaena sp.could be promoted significantly until phosphorus level attained 0.12 mg/L,indicating that phosphorus is the main limiting nutrient source for Anabaena sp..For Yanghe reservoir,the nutrient level has already been enough for the growth of Anabaena sp..Therefore,the nutrient source content,especially phosphorus,should be reduced effectively to control the cyanobacterium bloom and taste and odor problems.