LAUSR

Biofilms are microbial colonies that are encapsulated in the extracellular polymer secreted by cells through their proliferation and differentiation. Biofilm exists on solid surfaces, liquid surfaces or in liquid media, where the growth of bacterial biofilm is closely related to the velocity of secondary flow, the main flow and the geometry of the channel; which are hard to measure in the natural fluid environment, making the study of the biofilm streamer growth process is difficult. In this paper, we use microfluidic channels made of polydimethylsiloxane to study the growth dynamics of Bacillus subtilis biofilm streamer in flow. We observed that the biofilm streamer growth undergoes three stages with different growth characteristics: firstly, we find that the initial growth of the streamer locates at the position with the maximum value of P= Secondary flow velocity×main flow velocity. Secondly, the biofilm undergoes the floating growth around the micro column obstacle. Finally, after the transition stage, the last growth stage includes two types due to different attaching strength and mechanical properties of the biofilm. Our research provides new insights into the formation and shedding of biofilm streamer in natural and industrial environments, and helps us better understand the biofilm growth in fluid flow.