Showing papers on "Biofilm published in 1986"
01 Nov 1986
TL;DR: The metabolic activity of diatoms appears to be the rate-limiting process in biofilm development on illuminated surfaces under conditions of low bulk-water dissolved organic carbon.
Abstract: Algal-bacterial consortia attached to polystyrene surfaces were prepared in the laboratory by using the marine diatom Amphora coffeaeformis and the marine bacterium Vibrio proteolytica (the approved name of this bacterium is Vibrio proteolyticus. The organisms were attached to the surfaces at cell densities of approximately 5 x 10/sup 4/ cells cm/sup -2/ (diatoms) and 5 x 10/sup 6/ cells cm/sup -2/ (bacteria). The algal-bacterial consortia consistently exhibited higher rates of (/sup 3/H)thymidine incorporation than did biofilms composed solely of bacteria. The rates of (/sup 3/H)thymidine incorporation by the algal-bacterial consortia were fourfold greater than the rates of incorporation by monobacterial biofilms 16 h after biofilm formation and were 16-fold greater 70 h after biofilm formation. Extracellular material released from the attached Amphora cells supported rates of bacterial activity (0.8 x 10/sup -21/ mol to 17.9 x 10/sup -21/ mol of (/sup 3/H)thymidine incorporated cell /sup -1/ h/sup -1/) and growth (doubling time, 29.5 to 1.4 days) comparable to values reported for a wide variety of marine and freshwater ecosystems. In the presence of sessile diatom populations, DNA synthesis by attached V. proteolytica cells was light dependent and increased with increasing algal abundance. The metabolic activity of diatoms thus appears tomore » be the rate-limiting process in biofilm development on illuminated surfaces under conditions of low bulk-water dissolved organic carbon.« less
93 citations
TL;DR: Moore et al. as discussed by the authors used the marine diatom Amphora coffeaeformis and the marine bacterium Vibrio proteolyticus to construct polystyrene surfaces and found that the algal-bacterial consortia consistently exhibited higher rates of [H]thymidine incorporation than did biofilms composed solely of bacteria.
Abstract: Algal-bacterial consortia attached to polystyrene surfaces were prepared in the laboratory by using the marine diatom Amphora coffeaeformis and the marine bacterium Vibrio proteolytica (the approved name of this bacterium is Vibrio proteolyticus [W. E. C. Moore, E. P. Cato, and L. V. H. Moore, Int. J. Syst. Bacteriol. 35:382-407, 1985]). The organisms were attached to the surfaces at cell densities of approximately 5 x 10 cells cm (diatoms) and 5 x 10 cells cm (bacteria). The algal-bacterial consortia consistently exhibited higher rates of [H]thymidine incorporation than did biofilms composed solely of bacteria. The rates of [H]thymidine incorporation by the algal-bacterial consortia were fourfold greater than the rates of incorporation by monobacterial biofilms 16 h after biofilm formation and were 16-fold greater 70 h after biofilm formation. Extracellular material released from the attached Amphora cells supported rates of bacterial activity (0.8 x 10 to 17.9 x 10 mol of [H]thymidine incorporated cell h) and growth (doubling time, 29.5 to 1.4 days) comparable to values reported for a wide variety of marine and freshwater ecosystems. In the presence of sessile diatom populations, DNA synthesis by attached V. proteolytica cells was light dependent and increased with increasing algal abundance. The metabolic activity of diatoms thus appears to be the rate-limiting process in biofilm development on illuminated surfaces under conditions of low bulk-water dissolved organic carbon.
92 citations
TL;DR: In this article, it has been shown theoretically that the diffusional resistance to the transport in the biofilm of the inorganic carbon species as affected by the acidity production in a nitrifying biofilm gives rise to a decreased pH in the interior of the biofilms.
85 citations
TL;DR: Exopolysaccharide secreted by the bacteria develops a matrix or glycocalyx that appears to protect the biofilm-forming sessile bacteria from antibiotics.
37 citations
TL;DR: In this paper, the loss of biofilm during a conventional preparation procedure was evaluated and a different technique was devised to carry a biofilm sample through the preparation stage with reduced losses.
32 citations
TL;DR: Direct observation of theBiofilm mode of bacterial growth on Hemasites suggests that the colonizing organisms will not be completely recovered by routine microbiologic techniques and that bacteria in the biofilm will tend to resist both host clearance mechanisms and antibiotic therapy.
16 citations
Dissertation•
01 Jan 1986
TL;DR: Investigation of the effect of calcium on cellular reproduction and extracellular polymer formation by Pseudomonas aeruginosa in a biofilm suggests that free calcium (or calcium-assisted ligands) is essential to the structural integrity of the biofilm.
Abstract: Bacteria exhibit a tendency for adsorbing to and colonizing surfaces which are submerged in aquatic environments. Adsorption is mediated by extracellular polymeric material which is formed by the bacteria and extends from the cell to the attachment surface. The attached cells reproduce and form additional extracellular polymer increasing the mass of the deposit. The cellular-extracellular matrix is termed a bipfilm. The purpose of this study was to investigate the effect of calcium on cellular reproduction and extracellular polymer formation by Pseudomonas aeruginosa in a biofilm. Experiments were conducted with a pure culture of Ps. aeruginosa using fixed film bioreactors with glucose serving as the limiting nutrient. Results indicate calcium increases the rate and extent of cellular carbon accumulation at the surface. However, there was no effect of calcium on the amount of polymer carbon accumulated on the surface. Results also suggest that free calcium (or calcium-assisted ligands) is essential to the structural integrity of the biofilm. The energy required for biochemical conversion of glucose into biomass by suspended or immobilized culture of Ps. aeruginosa was constant and was independent of time, biomass concentration, specific cellular growth rate, and calcium concentration in the medium. THE INFLUENCE OF CALCIUM ON BIOFILM PROCESSES by Mukesh Harilal Turakhia A thesis submitted in partial fulfillment, of the requirements for the degree of Doctor of Philosophy in ■ ' Chemical Engineering MONTANA STATE UNIVERSITY Bozeman, Montana March 1986.
8 citations
TL;DR: A mathematical biofilm model considering diffusion and decomposition of a single substrate was developed, and simplified approximate relationships between net removal rates and normalized biofilm parameters were obtained theoretically.
Abstract: A mathematical biofilm model considering diffusion and decomposition of a single substrate was developed, and simplified approximate relationships between net removal rates and normalized biofilm parameters were obtained theoretically. Long term experiments on acetate treatment with methanogen attached biofilm reactors were carried out, and removal rates were analized by using the present model. Variations of biofilm parameters which specified treatment characteristics were represented as a function of the attached biomass. By using these parameters, treatment characteristics of methanogen attached biofilm reactors are simply and accurately evaluated.
7 citations
01 Jan 1986
Abstract: In order to get basic information concerning the application of a biological treatment to the ammonia nitrogen removal from drinking water, we considered the relation between the biofilm development of nitrifying bacteria and the fluid flow The experiment showed the high dependence of the biofilm development on the shear velocity There exists a suitable shear velocity which gives the maximum biofilm accumulation The increase of the shear velocity accelerated both the ammonia removal and biofilm detachment We made a biofilm growth model and examined the growth curve in relation to the shear velocity
1 citations
TL;DR: Time-dependent biofilm formation effects on continuous fermenter operation are modelled here for a binary culture of microorganisms growing on a single substrate.
Abstract: Time-dependent biofilm formation effects on continuous fermenter operation are modelled here for a binary culture of microorganisms growing on a single substrate. Dynamic computer solutions are detailed for a mixed culture of one microbe a having a higher growth rate than a second microbe b for two hypothetical scenarios of microbe b having different magnitudes of cellular deposition rate. A stability analysis of the resultant steady-states is also provided. Biofilm effects on the estimation of kinetic and stoichiometric parameters in a chemostat plus the impact of biofilms on mixed culture dynamics are discussed.
1 citations