Locomotion of bacteria in liquid flow and the boundary layer effect on bacterial attachment.
The formation of biofilm greatly affects the performance of biological reactors, which highly depends on bacterial swimming and attachment that usually takes place in liquid flow. Therefore, bacterial swimming and attachment on flat and circular surfaces with the consideration of flow was studied experimentally. Besides, a mathematical model comprehensively combining bacterial swimming and motion with flow is proposed for the simulation of bacterial locomotion and attachment in flow. Both experimental and theoretical results revealed that attached bacteria density increases with decreasing boundary layer thickness on both flat and circular surfaces, the consequence of which is inherently related to the competition between bacterial swimming and the non-slip motion with flow evaluated by the Péclet number. In the boundary layer, where the Péclet number is relatively higher, bacterial locomotion mainly depends on bacterial swimming. Thinner boundary layer promotes bacterial swimming towards the surface, leading to higher attachment density. To enhance the performance of biofilm reactors, it is effective to reduce the boundary layer thickness on desired surfaces.
Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030, China; Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030, China. Electronic address: zhangchao@cqu.edu.cn.
Chao
C
Zhang
Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030, China; Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030, China. Electronic address: lqzx@cqu.edu.cn.
Qiang
Q
Liao
Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030, China; Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030, China. Electronic address: rchen@cqu.edu.cn.
Rong
R
Chen
Key Laboratory of Low-grade Energy Utilization Technologies and Systems (Chongqing University), Ministry of Education, Chongqing 400030, China; Institute of Engineering Thermophysics, Chongqing University, Chongqing 400030, China. Electronic address: zhuxun@cqu.edu.cn.
Xun
X
Zhu
D001422:Bacterial Adhesion / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D003198:Computer Simulation; D004926:Escherichia coli / Q000166:cytology* / Q000502:physiology*; D008124:Locomotion / Q000502:physiology*; D008954:Models, Biological; D009038:Motion; D012212:Rheology / Q000379:methods*; D033081:Shear Strength / Q000502:physiology; D013314:Stress, Mechanical
Attachment; Bacteria; Biofilm; Boundary layer; Liquid flow; Locomotion