Influence of hydrodynamics and nutrients on biofilm structure

Hydrodynamic conditions control two interlinked parameters; mass transfer and drag, and will, therefore, significantly influence many of the processes involved in biofilm development. The goal of this research was to determine the effect of flow velocity and nutrients on biofilm structure. Biofilms were grown in square glass capillary flow cells under laminar and turbulent flows. Biofilms were observed microscopically under flow conditions using image analysis. Mixed species bacterial biofilms were grown with glucose (40 mg/l) as the limiting nutrient. Biofilms grown under laminar conditions were patchy and consisted of roughly circular cell clusters separated by interstitial voids. Biofilms in the turbulent flow cell were also patchy but these biofilms consisted of patches of ripples and elongated ‘streamers' which oscillated in the flow. To assess the influence of changing nutrient conditions on biofilm structure the glucose concentration was increased from 40 to 400 mg/l on an established 21 day old biofilm growing in turbulent flow. The cell clusters grew rapidly and the thickness of the biofilm increased from 30 μ to 130 μ within 17 h. The ripples disappeared after 10 hours. After 5 d the glucose concentration was reduced back to 40 mg/l. There was a loss of biomass and patches of ripples were re‐established within a further 2 d.

[1]  Z Lewandowski,et al.  Oscillation characteristics of biofilm streamers in turbulent flowing water as related to drag and pressure drop. , 1998, Biotechnology and bioengineering.

[2]  C. Picioreanu,et al.  Influence of biomass production and detachment forces on biofilm structures in a biofilm airlift suspension reactor , 1998, Biotechnology and bioengineering.

[3]  Brain Butterworth.  Biofilm Growth and Hydraulic Performance , 1981 .

[4]  W. G. Characklis.  Bioengineering report: Fouling biofilm development: A process analysis , 1981 .

[5]  M. V. van Loosdrecht,et al.  Heterogeneity of biofilms in rotating annular reactors: Occurrence, structure, and consequences , 1994, Biotechnology and bioengineering.

[6]  J M Tiedje,et al.  Channel structures in aerobic biofilms of fixed-film reactors treating contaminated groundwater , 1995, Applied and environmental microbiology.

[7]  S. Møller,et al.  Impact of nutrient composition on a degradative biofilm community , 1997, Applied and environmental microbiology.

[8]  D. de Beer,et al.  Liquid flow in heterogeneous biofilms , 1994, Biotechnology and bioengineering.

[9]  J. Wimpenny.  Ecological determinants of biofilm formation. , 1996, Biofouling.

[10]  Paul Stoodley,et al.  Relation between the structure of an aerobic biofilm and transport phenomena , 1995 .

[11]  D. Beer,et al.  Liquid flow and mass transport in heterogeneous biofilms , 1996 .

[12]  J. Costerton,et al.  Optical sectioning of microbial biofilms , 1991, Journal of bacteriology.

[13]  Zbigniew Lewandowski,et al.  Effects of biofilm structures on oxygen distribution and mass transport , 1994, Biotechnology and bioengineering.

[14]  I. Ozturk,et al.  The effect of anaerobic pre-treatment on the inert soluble COD of fermentation industry effluents , 1995 .

[15]  J. Costerton,et al.  Observations of fouling biofilm formation. , 1981, Canadian journal of microbiology.

[16]  O. Petrini,et al.  Fungal saprobes and pathogens as endophytes of rice (Oryza sativa L.) , 1992 .

[17]  Peter A. Wilderer,et al.  Anisotropic morphology and fractal dimensions of biofilms , 1996 .

[18]  James D. Bryers,et al.  Early fouling biofilm formation in a turbulent flow system: Overall kinetics , 1981 .

[19]  J. Lawrence,et al.  Analysis of biofilm formation using 2D vs 3D digital imaging , 1993 .

[20]  Alfred B. Cunningham,et al.  Biofilm structure and influence on biofouling under laminar and turbulent flows , 1999 .

[21]  Z. Lewandowski,et al.  Liquid Flow in Biofilm Systems , 1994, Applied and environmental microbiology.

[22]  King Eo,et al.  Two simple media for the demonstration of pyocyanin and fluorescin. , 1954 .

[23]  Bjarke Bak Christensen,et al.  In Situ Gene Expression in Mixed-Culture Biofilms: Evidence of Metabolic Interactions between Community Members , 1998, Applied and Environmental Microbiology.

[24]  Arthur R. M. Nowell,et al.  Turbulent flow in a depth‐limited boundary layer , 1979 .

[25]  Zbigniew Lewandowski,et al.  Flow induced vibrations, drag force, and pressure drop in conduits covered with biofilm , 1995 .

[26]  Waleed M. Zahid,et al.  A technique for a characterization of RBC biofilm surface , 1994 .

[27]  H. Lappin-Scott,et al.  Relationship between mass transfer coefficient and liquid flow velocity in heterogenous biofilms using microelectrodes and confocal microscopy. , 1997, Biotechnology and bioengineering.