Biofilm development

Zellner, G., Geveke, M., de Macario, E. C., and Diekmann, H., Population Dynamics of Biofilm Development During Start-Up of a Butyrate-Degrading Fluidized-Bed Reactor, Appl. Microbiol. Biotechnol., 36 404 (1991)... 

Fig. 2. Scanning electron micrograph showing a natural microbial biofilm developed on surface of immobilized surface when dimethylphthalate was used as the sole source of carbon and energy after dehydration and critical-point dried and coating with palladium and gold (unpublished results). 

Some less-than-rapid methods may also be considered in process if they are used to modify or enhance the process. Cheung et al. did some work in examining alterations in extracellular substances during biofilm development of Pseudomonas aeruginosa on aluminum plates.25 The FT-IR spectra, taken over days, showed changes by the fifth day. They believe that structural changes or... 

Koo, H., Nino de Guzman, P., Schobel, B. D., Vacca Smith, A. V., and Bowen, W. IT. (2006). Influence of cranberry juice on glucan-mediated processes involved in Streptococcus mutans biofilm development. Caries Res. 40, 20-27. 

These techniques are limited to systems that are compatible with the higher temperatures needed to achieve sanitization, such as stainless steel and some polymer formulations. Although thermal methods control biofilm development, they are not effective in removing established biofilms. 

O Toole, G. A., and R. Kolter. 1998. Flagellar and twitching motility are necessary for Pseudomonas aeruginosa biofilm development. Molecular Microbiology 30 295-304. 

Sinsabaugh, R. L., S. W. Golladay, and A. E. Linkins. 1991. Comparison of epilithic and epixylic biofilm development in a boreal river. Freshwater Biology 25 179-187. 

Pichette, C., H. Zhang, W. Davison, and S. Sauve. 2007. Preventing biofilm development on devices using metals and antibiotics. Talanta 72 716-722. 

The buildup of biofilm on the membrane surface means an additional resistance to solvent flow as well as the possibility of enhancement of CP level by the biofilm, which is similar to the case of colloidal fouling [32,36], In general, the diffusivity is linked to the tortuosity factor of the biofilm [37]. Hence, it is likely that the backdiffusion of solutes in the biofilm on RO is hindered. The enhanced CP is important for two reasons. Firstly, the elevated concentration of solutes at the membrane wall means an increase in the osmotic pressure (CEOP) and hence a loss in the effective TMP. Secondly, the nutrient level is also enhanced and this will further accelerate the growth of the biofilm [32,36]. So, biofouling in RO becomes an interplay between C P and biofilm development. 

Figure 11. A-B illustrating the effect of the NaOH/AgNC>3 wet treatment of native PVC on survival of biofilm cells. Graph A. illustrates the evolution of the total biofilm population for both native and NaOH + AgNCh treated PVC. B illustrates the sterility of the supernatant following the Na0H/AgN03 modification (right), where the supernatant following biofilm development on the native PVC surface is illustrated on the left.18...

M. H. Rashid, K. Rumbaugh, L. Passador, D. G. Davies, N. Hamood, B. H. Iglewski and A. Kornberg (2000b). Polyphosphate kinase is essential for biofilm development, quorum sensing, and virulence of Pseudomonas aeruginosa. Proc. Natl. Acad. Sci. USA, 97, 9636-9641. 

The EHD method with a RDE has been applied to the characterisation of porous layers of corrosion products formed on carbon steel [110], for the characterisation of salt films formed on copper [90, 111, 112] and iron [113], and for biofilms developed in natural seawater [114]. Corrosion inhibition films formed by an organic surfactant acting on the surface of pure iron have been characterised in this way, too [115]. An effect of a... 

Junker, L.M. and Clardy, J. 2007. High-throughput screens for small-molecule inhibitors of Pseudomonas aeruginosa biofilm development. Antimicrob. Agents Chemother. 51, 3582-3590. 

Environmental conditions related to rock surface exposure have profound effects on biofilm development, as metabolic activity and growth are directly connected to the availability of water, energy sources and nutrients, as well as to conditions of temperature and irradiation. Another important factor for establishment of subaerial biofilms is the resistance of the supporting substrate to environmentally and biologically influenced disintegration and dissolution (wear-down). Rapidly weathering rock surfaces (e.g. porous sandstone in an intertidal coastal zone) show little or... 

Purevdoij-Gage, B., Orr, M.E., Stoodley, R, Sheehan, K.B., Hyman, L.E. (2007). The role of FLOll in Saccharomyces cerevisiae biofilm development in a laboratory based flow-cell system. FFMS Yeast Res., 7, 372-379. 

Biofilm development is affected by both physical and chemical factors. The abundance and condition of bacteria in the water column plays a major role in initial rate of settlement on a surface 181]. Surface factors such as wettability [82] and critical surface tension [83], surface hydrophobicity [84], fluid dynamic forces [85], shear stress [86], electrolyte concentration [87] and metabolic inhibitors [88] can all affect microbial attachment, adhesion or growth. The low surface energy of a gorgonian octocoral has been implicated as a passive fouling resistance mechanism used in conjunction with other antifouling defences [82]. 

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