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水体中生物膜的生长特性及其对微囊藻毒素的吸附与降解研究
Alternative TitleStudy on the Biofilm Growth Characteristics in Aquatic Environment and the Adsorption and Biodegradation of Microcystins by Biofilms
梅琼
Subtype硕士
Thesis Advisor刘剑彤
2007-06-14
Degree Grantor中国科学院水生生物研究所
Place of Conferral水生生物研究所
Keyword东湖 生物膜 微囊藻毒素 吸附 生物降解
Abstract蓝藻水华污染及其释放的微囊藻毒素对环境的危害已成为全球关注的环境问题,水体中微囊藻毒素的去除已成为研究的重点。在自然环境条件下,生物膜存在于几乎所有暴露于水体中的固体表面上,因而生物膜对水体中污染物的转移和归趋有一定的影响。本研究采用一种自行设计的简便生物膜采样装置,在富营养化浅水湖泊—武汉东湖20和100 cm水深处自然培养和收集生物膜,考察其形成、发育及活性特征,旨在深化对水体中生物膜生物化学特性的认识;其次,分别研究了不同水深处的生物膜对微囊藻毒素的吸附和不同水深、相同培养时间以及同一水深、不同培养时间的生物膜对微囊藻毒素的生物降解作用,目的在于揭示生物膜对水体中微囊藻毒素环境行为的作用机制,为用生物手段控制和治理水体微囊藻毒素污染提供理论依据和技术指导。 主要研究结果如下: (1) 水体中生物膜的生长受光照、水温、pH、DO和营养盐等因素的影响,并且,气候和水文条件也会影响生物膜的生长发育。随着生长时间的延长,武汉东湖秋季水体中生物膜生长经历了潜伏适应期、增长期、脱落期和恢复生长期四个阶段,生物膜的胞外聚糖、COD和脱氢酶活性与生物膜的生物量均存在显著性正相关关系,20 cm水深处培养的生物膜的生长速度快于100 cm水深处培养的生物膜,并且,生物量和活性均高于100 cm水深处培养的生物膜。 (2) 东湖水体中培养15d的生物膜可以吸附MC-RR,吸附平衡时间约为6-8h,平衡时最大吸附量占初始MC-RR总量的6.94%。随着MC-RR平衡浓度的增加,MC-RR在生物膜上的吸附量逐渐增加,并且,MC-RR在生物膜上的吸附行为用Langmuir吸附等温式来描述最贴切(R>0.99)。pH值和离子强度都会影响MC-RR在生物膜上的吸附,pH值的降低或离子强度的增大都会促进MC-RR在生物膜上的吸附。 (3) 东湖水体中培养的生物膜在有氧条件下对MC的降解经历了2-3d的延滞期,在降解过程中,溶液的pH值持续上升。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,生物膜对MC的降解效果与生物膜的培养时间密切相关。另外,生物膜对MC的降解过程服从方程y=A/[1+Bexp(-Ct)],降解速率随反应温度的升高和生物膜上微生物量的增加而加快。
Other AbstractThe pollution of microcystins (MC) following the breaking out of cyanobacterial bloom has raised more and more concerns; the removal of MC in water body has been a focus of attention. In natural environment, biofilms formed in the surface of submerged mineral particles, the transport and persistence of pollutant in aquatic system can be influenced by their adsorption onto biofilms and the remobilization of biofilms. In this research, a kind of self-designed simple biofilm collection device was uesd to culture and collect the biofilm in different depths (20 cm and 100 cm water depth) of the Donghu Lake of Wuhan City, and the characteristics of their growth and activity were studied. It aimed to understand further the biochemical characteriatics of biofilms; In the addition, the adsorption of MC on the biofilms in different water depths, and the biodegradation of MC with the biofilms cultured in different water depths for same times as well as in same water depths for different times were investigated. The purpose was to reveal the environmental behaviors of MC, hoping to support theoretical accordings and technique instruction for controlling the MC pollution in aquatic environment with the biology method. The main results were summarized as follows: 1. The growth of biofilms in natural water was influenced by such factors as photic condition, water temperature, pH, dissolved oxygen (DO) and nutrient level, meteorological and hydrological conditions also influenced it. The growth of biofilms formed in Lake Donghu in autumn went through four periods like “the latent adaptation period-the increasing period-the detachment period-the renewing period”, the extraeclluar polysaccharides, COD and dehydrogenase of biofilm were positive correlated with the biofilm biomass, and the growth rate of biofilms developed in the water depth of 20 cm was faster than that in the water depth of 100 cm, furthermore, the biomass of biofilm developed in the water depth of 20 cm was larger and its activity was higher than that in the water depth of 100 cm. 2. The biofilms cultured in Lake Donghu for 15d could adsorb MC-RR, the adsorption balance time was about 6-8h, and the maximum adsorption amount was 6.94% of the initial MC-RR amount. The adsorption amount of MC-RR gradually increased with the balance concentrate of MC-RR increasing, and moreover, the adsorption behavior of MC-RR onto biofilms could be well described by the Langmuir adsorption isotherm(R>0.99). The pH and the ionic strength could affect the adsorption of MC-RR, and the lower pH or increasing ionic strength could enhance the biofilms adsorption of MC-RR. 3. The biodegradation of MC by biofilms cultured in Lake Donghu under oxygen-containing conditions experienced the lag period of 2-3d. During the biodegradation, the pH of solution rise steadily, and the degradation rate with the biofilms cultured in water depth of 20 cm was faster than that in the water depth of 100 cm, and the degradation rate improved as the number of the slides adhering biofilms increased. Also, the degradation of MC was closely relative to the biofilms culture time. The biodegradation process could be described as the equation: y=A/[1+Bexp(-Ct)], the degradation rate increased as the temperature became high or microbial biomass were large.
Pages56
Language中文
Document Type学位论文
Identifierhttp://ir.ihb.ac.cn/handle/342005/12202
Collection学位论文
Recommended Citation
GB/T 7714
梅琼. 水体中生物膜的生长特性及其对微囊藻毒素的吸附与降解研究[D]. 水生生物研究所. 中国科学院水生生物研究所,2007.
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