ABSTRACT
A novel approach was developed for the construction of biofilms with defined internal architecture using AC electrokinetics and flocculation. Artificial structured microbial consortia (ASMC) consisting of localized layered microcolonies of different cell types were formed by sequentially attracting different cell types to high field regions near microelectrodes using dielectrophoresis. Stabilization of the microbial consortia on the electrode surface was achieved by crosslinking the cells using the flocculant polyethyleneimine (PEI). Consortia of Escherichia coli, Micrococcus luteus, and Saccharomyces cerevisiae were made as model systems. Also, more natural consortia were made of the bacteria Pseudomonas putida, Clavibacter michiganense, and Methylobacterium mesophilum, which are found together in consortia during biodegradation of metal-cutting waste fluids.
Subject(s)
Bacterial Adhesion/drug effects , Biofilms/growth & development , Cell Culture Techniques/methods , Electrophoresis/methods , Polyethyleneimine/pharmacology , Actinomycetales/cytology , Actinomycetales/drug effects , Actinomycetales/physiology , Bacterial Adhesion/radiation effects , Biofilms/drug effects , Biofilms/radiation effects , Dose-Response Relationship, Drug , Electromagnetic Fields , Escherichia coli/cytology , Escherichia coli/drug effects , Escherichia coli/physiology , Flocculation , Methylobacterium/cytology , Methylobacterium/drug effects , Methylobacterium/physiology , Micrococcus luteus/cytology , Micrococcus luteus/drug effects , Micrococcus luteus/physiology , Pseudomonas putida/cytology , Pseudomonas putida/drug effects , Pseudomonas putida/physiology , Saccharomyces cerevisiae/cytology , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/physiologyABSTRACT
A method was developed for the measurement of the bacterial particle conductivity, based on the measurement of the conductivity of a bacterial cell suspension sigma(s) and the suspending medium sigma(m). A line plotted through sigma(s) - sigma(m) versus sigma(m) crosses the x-axis at sigma(m) = sigma(p), independent of the bacterial cell concentration. The method does not require anything more complex than a centrifuge and a conductivity meter. Knowledge of the bacterial particle conductivity is of importance in, for example, the dielectrophoretic separation, manipulation and trapping of bacterial cells, as well as the study of their physiological state.
