Abstract
Many metal reducing bacteria are motile with their run-and-tumble behavior exhibiting series of flights and waiting-time spanning multiple orders of magnitude. While several models of bacterial processes do not consider their ensemble motion, some models treat motility using an advection diffusion equation (ADE). In this study, Geobacter and Pelosinus, two metal reducing species, are used in micromodel experiments for study of their motility characteristics. Trajectories of individual cells on the order of several seconds to few minutes in duration are analyzed to provide information on (1) the length of runs, and (2) time needed to complete a run (waiting or residence time). A Continuous Time Random Walk (CTRW) model to predict ensemble breakthrough plots is developed based on the motility statistics. The results of the CTRW model and an ADE model are compared with the real breakthrough plots obtained directly from the trajectories. The ADE model is shown to be insufficient, whereas a coupled CTRW model is found to be good at predicting breakthroughs at short distances and at early times, but not at late time and long distances. The inadequacies of the simple CTRW model can possibly be improved by accounting for correlation in run length and waiting time.
Highlights
The complex and interacting processes of bacterial transport impart a self-propelling character to many species[1]
As a first step in an effort to develop improved simulators for metal bioremediation, we studied motility characteristics and construct simple micro-scale transport models for two microorganisms: the model metal-reducing bacterium Geobacter sulfurreducens and Pelosinus strain JHL-11, an organism isolated from the uranium- and nitrate-contaminated groundwater of the 300 Area, and chromium contaminated groundwater of the 100 Area, of the U.S Department of Energy’s (DOE’s) Hanford Site, in southeastern Washington State[21]
Though many metal reducing bacteria are motile with their run-lengths and waiting-time spanning a wide range of values, existing models of contaminant bioreduction do not account for the movement of microorganisms, either passive movement with flowing groundwater or active movement by motile bacteria
Summary
The complex and interacting processes of bacterial transport impart a self-propelling character to many species[1]. Many models used to study the ensemble behavior of bacterial transport are based on the use of advection-diffusion equation (ADE)[10,11,12,13,14,15]. As a first step in an effort to develop improved simulators for metal bioremediation, we studied motility characteristics and construct simple micro-scale transport models for two microorganisms: the model metal-reducing bacterium Geobacter sulfurreducens (strain PCA, the type strain of the species) and Pelosinus strain JHL-11, an organism isolated from the uranium- and nitrate-contaminated groundwater of the 300 Area, and chromium contaminated groundwater of the 100 Area, of the U.S Department of Energy’s (DOE’s) Hanford Site, in southeastern Washington State[21]. We present here experiments and models using motile strains of Geobacter and Pelosinus to quantify their motion properties and ensemble transport in unobstructed medium, as a prelude to development and testing of new models of bacterial transport during bioremediation
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
