Metabolic differentiation in biofilms as indicated by carbon dioxide production rates
Date
2010
Authors
Bester E.
Kroukamp O.
Wolfaardt G.M.
Boonzaaier L.
Liss S.N.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The measurement of carbon dioxide production rates as an indication of metabolic activity was applied to study biofilm development and response of Pseudomonas sp. biofilms to an environmental disturbance in the form of a moving air-liquid interface (i.e., shear). A differential response in biofilm cohesiveness was observed after bubble perturbation, and the biofilm layers were operationally defined as either shear-susceptible or non-shear-susceptible. Confocal laser scanning microscopy and image analysis showed a significant reduction in biofilm thickness and biomass after the removal of the shear-susceptible biofilm layer, as well as notable changes in the roughness coefficient and surface-to-biovolume ratio. These changes were accompanied by a 72% reduction of whole-biofilm CO2 production; however, the non-shear-susceptible region of the biofilm responded rapidly after the removal of the overlying cells and extracellular polymeric substances (EPS) along with the associated changes in nutrient and O2 flux, with CO2 production rates returning to preperturbation levels within 24 h. The adaptable nature and the ability of bacteria to respond to environmental conditions were further demonstrated by the outer shear-susceptible region of the biofilm; the average CO2 production rate of cells from this region increased within 0.25 h from 9.45 ± 5.40 fmol of CO2 · cell -1 ·; h-1 to 22.6 ± 7.58 fmol of CO 2 ·cell-1 ·h-1 when cells were removed from the biofilm and maintained in suspension without an additional nutrient supply. These results also demonstrate the need for sufficient monitoring of biofilm recovery at the solid substratum if mechanical methods are used for biofouling control. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Description
Keywords
Bio-film thickness, Biofilm development, Biofouling control, Biovolumes, Confocal laser scanning microscopy, Differential response, Environmental conditions, Environmental disturbances, Extracellular polymeric substances, Mechanical methods, Metabolic activity, Moving air, Nutrient supply, Production rates, Pseudomonas sp, Roughness coefficient, Solid substrata, Bacteria, Biofilms, Carbon dioxide, Confocal microscopy, Image analysis, Metabolism, Nutrients, Phase interfaces, Biofilters, carbon dioxide, green fluorescent protein, recombinant protein, biofilm, biofouling, carbon dioxide, environmental disturbance, image analysis, nutrient cycling, perturbation, scanning electron microscopy, article, biofilm, biological model, biomechanics, confocal microscopy, flow kinetics, genetics, growth, development and aging, kinetics, metabolism, microbiology, physiology, plankton, Pseudomonas, shear strength, Biofilms, Biomechanics, Carbon Dioxide, Environmental Microbiology, Green Fluorescent Proteins, Kinetics, Microscopy, Confocal, Models, Biological, Plankton, Pseudomonas, Recombinant Proteins, Rheology, Shear Strength, Pseudomonas sp.
Citation
Applied and Environmental Microbiology
76
4
76
4