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题名	盐藻细胞的表面特性和气泡吸附采收
作者	崔景芹
学位类别	硕士
答辩日期	2003
授予单位	中国科学院过程工程研究所
授予地点	中国科学院过程工程研究所
导师	蔡昭铃
关键词	盐藻 表面特性 泡沫分离 溶气气浮 速率常数
其他题名	Surface Characteristics of Dunaliella salina and Harvest of Cells by Bubble Adsorption
学位专业	生物化工
中文摘要	盐藻具有很高的经济价值,已实现了大规模培养,但当前采用的细胞采收方法仍有较多不足之处.该文对与采收密切相关的细胞表面特性作了初步研究,并据此考察了不添加表面活性剂的泡沫分离法和不添加絮凝剂的溶气气浮法采收盐藻细胞的可行性,确定了比较适宜的采收条件.
英文摘要	Dunaliella salina, a kind of microalgae with high commercial value, has been successfully cultivated in large scale. However the technology currently used to harvest D. salina cells has many shortages due to cells' frangibility and low cell density in culture liquid. Thus, in this paper, the cell membrane characteristics, one of the key factors that affected the harvest efficiency, was studied, and the harvest of the cells by the methods of foam separation without adding surfactant and dissolved air flotation (DAF) without adding floatation agent was investigated. Membrane -potential of Dunaliella salina cell was measured by the determination of cells'- electrophoretic mobility. It showed that the -potential was negative at neutral pH, and became more negative with increasing pH and decreasing conductivity. By the method of microbial adherence to n-hexadecane, the hydrophobicity of vegetative cells was determined to be 20%~27% at pH 3.5-9.0, and the highest value of 27% at pH7.5. The hydrophobicity increased to 88.6% at pHl 0.5 because of cells' self-aggregation. Experiments of harvesting D. salina cells by batch foam separation (BFS) without adding surfactant were carried out in a 200-ml column. Under the optimum operation conditions obtained by orthogonal experiments, the cell harvest rate (R) reached above 90% and the enrichment factor (E) reached 30. The effects of alga liquid pH, initial cell concentration (Co) and gas flow-rate (Qg) on the cell harvest were also investigated. The results showed that the optimum pH of 7.5 for the harvest was coincident with the pH value at which the cell hydrophobicity was the highest. The hydrophobic adsorption of the cell-bubble was the key factor affecting the cell harvest in BFS. Co and Qg mainly influenced the hydrodynamic characteristics of the harvest system. When their value exceeded a certain range, the harvest efficiency was decreased. Experiments of harvesting D. salina cells were also carried out by batch DAF without adding floatation agent when cells self-aggregated at pH10.5~11.5, and the cell harvest rate was above 90%. But it was less than 40% when pH was lower than 10.5, indicating the formation of floes was necessary to increase the harvest efficiency in DAF. In our experimental condition range, the higher the air dissolving pressure (Ps), the better the harvest efficiency. Water flow rate (Qw) and the ratio (o.wf) of water volume to alga liquid volume affected the hydrodynamic behavior of the system, thereafter the cell floes flow, and both Qw and olwf had optimal values. The kinetics of D. salina cells/flocs harvest process by flotation can be described by the first-order reaction kinetics. In the process of BFS, the rate constant k was greater at lower pH. In the process of BDAF, k increased firstly then decreased with increasing awF and Qw-The great deal of micro bubbles at high Ps contributed to the increase of k. From the experimental results and kinetic analysis, it was drawn that the control step may be the cell-bubble adsorption in BFS process, while in DAF process, may be the rising of floes.
语种	中文
公开日期	2013-09-16
页码	94
内容类型	学位论文
源URL	[http://ir.ipe.ac.cn/handle/122111/1364]
专题	过程工程研究所_研究所（批量导入）
推荐引用方式 GB/T 7714	崔景芹. 盐藻细胞的表面特性和气泡吸附采收[D]. 中国科学院过程工程研究所. 中国科学院过程工程研究所. 2003.

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