scholarly journals Pronounced Effect of the Nature of the Inoculum on Biofilm Development in Flow Systems

2010 ◽  
Vol 76 (18) ◽  
pp. 6025-6031 ◽  
Author(s):  
Otini Kroukamp ◽  
Romeo G. Dumitrache ◽  
Gideon M. Wolfaardt
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Removal Rate ◽  
Maximum Activity ◽  
Nutrient Concentrations ◽  
Lag Phase ◽  
Dominant Form ◽  
Biofilm Growth ◽  
Flow Systems ◽  
Biofilm Development

ABSTRACT Biofilm formation renders sessile microbial populations growing in continuous-flow systems less susceptible to variation in dilution rate than planktonic cells, where dilution rates exceeding an organism's maximum growth rate (μmax) results in planktonic cell washout. In biofilm-dominated systems, the biofilm's overall μmax may therefore be more relevant than the organism's μmax, where the biofilm μmax is considered as a net process dependent on the adsorption rate, growth rate, and removal rate of cells within the biofilm. Together with lag (acclimation) time, the biofilm's overall μmax is important wherever biofilm growth is a dominant form, from clinical settings, where the aim is to prevent transition from lag to exponential growth, to industrial bioreactors, where the aim is to shorten the lag and rapidly reach maximum activity. The purpose of this study was to measure CO2 production as an indicator of biofilm activity to determine the effect of nutrient type and concentration and of the origin of the inoculum on the length of the lag phase, biofilm μmax, and steady-state metabolic activity of Pseudomonas aeruginosa PA01 (containing gfp), Pseudomonas fluorescens CT07 (containing gfp), and a mixed community. As expected, for different microorganisms the lengths of the lag phase in biofilm development and the biofilm μmax values differ, whereas different nutrient concentrations result in differences in the lengths of lag phase and steady-state values but not in biofilm μmax rates. The data further showed that inocula from different phenotypic origins give rise to lag time of different lengths and that this influence persists for a number of generations after inoculation.

Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589

2008 ◽  
Vol 58 (6) ◽  
pp. 1221-1229 ◽  
Author(s):  
D. H. Dusane ◽  
Y. V. Nancharaiah ◽  
V. P. Venugopalan ◽  
A. R. Kumar ◽  
S. S. Zinjarde
Keyword(s):  
Yarrowia Lipolytica ◽  
Biofilm Formation ◽  
Edible Oils ◽  
Carbon Sources ◽  
Three Dimensional ◽  
Ecological Niches ◽  
Lag Phase ◽  
Biofilm Growth ◽  
Water Media ◽  
Biofilm Development

Biofilm formation by Yarrowia lipolytica, a biotechnologically important fungus in microtitre plates, on glass slide surfaces and in flow cell was investigated. In microtitre plates, there was a short lag phase of adhesion followed by a period of rapid biofilm growth. The fungus formed extensive biofilms on glass slides, whereas in flow-cells a multicellular, three-dimensional microcolony structure was observed. The isolate formed biofilms in seawater and in fresh water media at neutral pH when grown in microtitre plates. The carbon sources differentially affected formation of biofilms in microtitre plates. Lactic acid, erythritol, glycerol, glucose and edible oils supported the formation of biofilms, while alkanes resulted in sub-optimal biofilm development. A variation in the morphology of the fungus was observed with different carbon sources. The results point to the possible existence of highly structured biofilms in varied ecological niches from where the yeast is isolated.

scholarly journals Influence of sub-inhibitory antibiotics and flow condition on Staphylococcus aureus ATCC 6538 biofilm development and biofilm growth rate: BioTimer assay as a study model

2014 ◽  
Vol 67 (11) ◽  
pp. 763-769 ◽  
Author(s):  
Francesca Berlutti ◽  
Alessandra Frioni ◽  
Tiziana Natalizi ◽  
Fabrizio Pantanella ◽  
Piera Valenti
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Rate ◽  
Flow Condition ◽  
Biofilm Growth ◽  
Biofilm Development

scholarly journals Microfluidic study of effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength in microchannels

2018 ◽  
Author(s):  
Na Liu ◽  
Tormod Skauge ◽  
David Landa-Marbán ◽  
Beate Hovland ◽  
Bente Thorbjørnsen ◽  
...  
Keyword(s):  
Porous Media ◽  
Flow Velocity ◽  
Water Purification ◽  
Adhesive Strength ◽  
Nutrient Concentration ◽  
Nutrient Concentrations ◽  
Porous System ◽  
Hydrodynamic Conditions ◽  
Biofilm Growth ◽  
Biofilm Development

AbstractBiofilm accumulation in the porous media can cause plugging and change many physical properties of porous media. Up to now, applications of desired biofilm growth and its subsequent bioplugging have been attempted for various practices. A deeper understanding of the relative influences of hydrodynamic conditions including flow velocity and nutrient concentration, on biofilm growth and detachment is necessary to plan and analyze bioplugging experiments and field trials. The experimental results by means of microscopic imaging over a T-shape microchannel show that flow velocity and nutrient concentrations can have significant impacts on biofilm accumulation and adhesive strength in both flowing and stagnant microchannels. Increase in fluid velocity could facilitate biofilm growth, but that above a velocity threshold, biofilm detachment and inhibition of biofilm formation due to high shear stress were observed. High nutrient concentration prompts the biofilm growth, but was accompanied by a relatively weak adhesive strength. This research provides an overview of biofilm development in a hydrodynamic environment for better predicting and modelling the bioplugging associated with porous system in petroleum industry, hydrogeology, and water purification.IMPORTANCEIn the recent decade, the use of bacteria has become more and more important in many applications. Bioplugging caused by bacteria growth in porous media has been explored as a viable technique for some applications, such as bioremediation, water purification and microbial enhanced oil recovery (MEOR). In order to control biofilms/biomasses selectively/directionally plugging in desirable places, the role of hydrodynamic conditions on biofilm growth and detachment is essential to investigate. Herein, a T-shape microchannel was prepared to study effects of flow velocity and nutrient concentration on biofilm accumulation and adhesive strength at pore scale. Our results suggest that flow velocity and nutrient concentration could control biofilm accumulation in microchannels. The finding helps explain and predict the engineering bioplugging in porous media, especially for the selective plugging strategy of a MEOR field trial.

Kinetics and Modelling of Aerobic and Anaerobic Film Growth

1990 ◽  
Vol 22 (1-2) ◽  
pp. 147-170 ◽  
Author(s):  
B. Capdeville ◽  
K. M. Nguyen
Keyword(s):  
Growth Rate ◽  
Steady State ◽  
Accumulation Rate ◽  
Removal Rate ◽  
Carbon Substrate ◽  
Substrate Removal ◽  
Stable Conditions ◽  
Active Bacteria ◽  
Aerobic And Anaerobic ◽  
Very High

Our fundamental studies of the kinetics of growth and substrate removal by aerobic and anaerobic biofilms have shown that the process comprises six phases : the latent, dynamic, linear, decrease, stabilization and detachment phases. During these experiments we also observed:-steady state functioning in the liquid bulk from the end of the dynamic phase. At this point a very thin pseudo-thickness of biofilm was observed (50 µm maximum).-steady state functioning relative to the observed biofilm mass, reached in the stabilization phase, the corresponding thickness being generally several hundred microns. To explain this phenomenon we suggest a new biofilm modelling hypothesis, based on physiological aspects, which consists of defining two types of bacteria : active bacteria (Ma) responsible for substrate removal and characterized by a specific growth rate (µo), and inert or deactivated bacteria (Md) which play no role in the removal process but are responsible for the observed accumulation of biofilm. Using this hypothesis, it is possible to modelize the dynamic and linear phases of growth of total biofilm dry matter (Mb) and carbon substrate removal kinetics. This model enables the exponential growth rate (µo), the accumulation rate (K) and the maximum quantity of active bacteria (Ma)max to be calculated. In another series of experiments, we studied the influence on these parameters of several factors which affect growth, such as the carbon substrate concentration provided by the feed (So) and the dissolved oxygen for the aerobic biofilms. The results demonstrate that the biological constants are strongly dependent on (So). The same is true for the volumetric substrate removal rate(kov), which shows that the process always depends on the reaction. Thus we have established that the substrate metabolization reaction occurs at the biofilm-liquid interface, and that it is preferable to use thin biofilms for an attached culture industrial process. This has been done by optimizing the surface and volume properties of new granular materials called OSBG (Optimized Support for Biological Growth). Initial results, notably for three-phase fluidized bed carbon removal, show that it is possible to eliminate very high carbon loading (10 to 15 kg TOD.m3.day−1) under very stable conditions with a very small quantity of active biomass (0.5 D.W. m). In addition, excess sludge production is relatively low and respirometric studies performed in situ with a gas phase mass spectrometer confirm the very high catabolic activity of thin biofilm.

Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589

2008 ◽  
Vol 58 (12) ◽  
pp. 2467-2475 ◽  
Author(s):  
D. H. Dusane ◽  
Y. V. Nancharaiah ◽  
V. P. Venugopalan ◽  
A. R. Kumar ◽  
S. S. Zinjarde
Keyword(s):  
Yarrowia Lipolytica ◽  
Biofilm Formation ◽  
Edible Oils ◽  
Carbon Sources ◽  
Three Dimensional ◽  
Ecological Niches ◽  
Lag Phase ◽  
Biofilm Growth ◽  
Water Media ◽  
Biofilm Development

Biofilm formation by Yarrowia lipolytica, a biotechnologically important fungus in microtitre plates, on glass slide surfaces and in flow cell was investigated. In microtitre plates, there was a short lag phase of adhesion followed by a period of rapid biofilm growth. The fungus formed extensive biofilms on glass slides, whereas in flow-cells a multicellular, three-dimensional microcolony structure was observed. The isolate formed biofilms in seawater and in fresh water media at neutral pH when grown in microtitre plates. The carbon sources differentially affected formation of biofilms in microtitre plates. Lactic acid, erythritol, glycerol, glucose and edible oils supported the formation of biofilms, while alkanes resulted in sub-optimal biofilm development. A variation in the morphology of the fungus was observed with different carbon sources. The results point to the possible existence of highly structured biofilms in varied ecological niches from where the yeast is isolated.

Steady State Measurement of Oxygenation Capacity

1985 ◽  
Vol 17 (2-3) ◽  
pp. 303-311
Author(s):  
Kees de Korte ◽  
Peter Smits
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Plug Flow ◽  
Usual Method ◽  
Steady State Method ◽  
State Measurement ◽  
Flow Systems ◽  
Air System ◽  
State Method ◽  
Steady State Measurement

The usual method for OC measurement is the non-steady state method (reaeration) in tapwater or, sometimes, in activated sludge. Both methods are more or less difficult and expensive. The steady state method with activated sludge is presented. Fundamentals are discussed. For complete mixed aeration tanks, plug flow systems with diffused air aeration and carousels the method is described more in detail and the results of measurements are presented. The results of the steady state measurements of the diffused air system are compared with those of the reaeration method in tapwater. The accuracy of the measurements in the 3 systems is discussed. Measurements in other aeration systems are described briefly. It is concluded that the steady state OC measurement offers advantages in comparison with the non-steady state method and is useful for most purposes.

Shear Loss Characteristics of an Aerobic Biofilm

1992 ◽  
Vol 26 (3-4) ◽  
pp. 595-600 ◽  
Author(s):  
S. M. Rao Bhamidimarri ◽  
T. T. See
Keyword(s):  
Growth Rate ◽  
Shear Stress ◽  
Film Thickness ◽  
Removal Rate ◽  
Surface Growth ◽  
Phenol Removal ◽  
Concentric Cylinder ◽  
Substrate Utilisation ◽  
Utilisation Rate ◽  
Net Growth Rate

Growth and shear loss characteristics of phenol utilizing biofilm were studied in a concentric cylinder bioreactor. The net accumulation of the biofilm and the substrate utilisation were measured as a function of torque. Uniform biofilms were obtained up to a thickness of around 300 microns, beyond which the surface growth was non-uniform. The substrate utilisation rate, however, reached a constant value beyond film thickness of 50 to 100 microns depending on the operational torque. The maximum phenol removal rate was achieved at a shear stress of 3.5 Nm-2. The effect of shear stress on net growth rate was found to be described byand a zero net growth was obtained at a shear stress of 18.7 Nm-2.

Relations between carbon removal rates, biofilm size and density of a novel anaerobic reactor: the inverse turbulent bed

2000 ◽  
Vol 41 (4-5) ◽  
pp. 253-260 ◽  
Author(s):  
P. Buffière ◽  
R. Moletta
Keyword(s):  
Removal Rate ◽  
Removal Rates ◽  
Carbon Removal ◽  
Biofilm Growth ◽  
Loading Rates ◽  
Biomass Activity ◽  
High Turbulence ◽  
The One ◽  
High Level ◽  
Very High

An anaerobic inverse turbulent bed, in which the biogas only ensures fluidisation of floating carrier particles, was investigated for carbon removal kinetics and for biofilm growth and detachment. The range of operation of the reactor was kept within 5 and 30 kgCOD· m−3· d−1, with Hydraulic Retention Times between 0.28 and 1 day. The carbon removal efficiency remained between 70 and 85%. Biofilm size were rather low (between 5 and 30 μm) while biofilm density reached very high values (over 80 kgVS· m−3). The biofilm size and density varied with increasing carbon removal rates with opposite trends; as biofilm size increases, its density decreases. On the one hand, biomass activity within the reactor was kept at a high level, (between 0.23 and 0.75 kgTOC· kgVS· d−1, i.e. between 0.6 and 1.85 kgCOD·kgVS · d−1).This result indicates that high turbulence and shear may favour growth of thin, dense and active biofilms. It is thus an interesting tool for biomass control. On the other hand, volatile solid detachment increases quasi linearly with carbon removal rate and the total amount of solid in the reactor levels off at high OLR. This means that detachment could be a limit of the process at higher organic loading rates.

scholarly journals Characterisation of Lactobacillus rhamnosus VT1 and its effect on the growth of Candida maltosa YP1

2008 ◽  
Vol 25 (No. 5) ◽  
pp. 272-282 ◽  
Author(s):  
D. Liptáková ◽  
Ľ. Valík ◽  
A. Lauková ◽  
V. Strompfová
Keyword(s):  
Growth Rate ◽  
Incubation Temperature ◽  
Lactobacillus Rhamnosus ◽  
Microbial Interactions ◽  
Lag Phase ◽  
Regression Equations ◽  
Candida Maltosa ◽  
Food Protection ◽  
Spoilage Yeast ◽  
Standard Response

The combined effect of initial amount of 18 h <i>L. rhamnosus</i> VT1 inoculum and incubation temperature on the growth of <i>Candida maltosa</i> YP1, an oxidative food spoilage yeast strain, was primarily modelled and studied by standard response surface methodology. This study resulted in the following linear regression equations characterising lag time and growth rate of <i>C. maltosa</i> YP1 in milk in competition with the potentially protective lactobacillus strain. Lag-phase of <i>C. maltosa</i> was strongly influenced by the amount of lactobacillus inoculum (<i>V</i><sub>0</sub>) and incubation temperature (1/<i>T</i>). The synergic effect of both these factors was also evident as results from the equation lag = –33.50 + 186.38 × <i>V</i><sub>0</sub> × 1/<i>T</i> + 512.27 × 1/<i>T</i> – 5.511 × <i>V</i><sub>0</sub> (<i>R</i><sup>2</sup><sub>(λ)</sub> = 0.849). The growth rate was sufficiently described by the linear relation: <i>Gr</i><sub>Cm</sub> = –0.00046 + 0.0033 × <i>T</i> – 0.0016 × <i>V</i><sub>0 (<i>R</i><sup>2</sup><sub>(Gr)</sub> = 0.847). On the basis of these equations, the mutual microbial interactions and the potential application of the lactobacillus strains to food protection are discussed.

Bifunctional Composites for Biofilms Modulation on Cervical Restorations

2021 ◽  
pp. 002203452110181
Author(s):  
A.A. Balhaddad ◽  
I.M. Garcia ◽  
L. Mokeem ◽  
M.S. Ibrahim ◽  
F.M. Collares ◽  
...  
Keyword(s):  
Free Energy ◽  
Surface Free Energy ◽  
Contact Angles ◽  
Bacterial Biofilm ◽  
Dental Composite ◽  
Log P ◽  
Rrna Gene ◽  
Cervical Lesions ◽  
Biofilm Growth ◽  
Biofilm Development

Cervical composites treating root carious and noncarious cervical lesions usually extend subgingivally. The subgingival margins of composites present poor plaque control, enhanced biofilm accumulation, and cause gingival irritation. A potential material to restore such lesions should combine agents that interfere with bacterial biofilm development and respond to acidic conditions. Here, we explore the use of new bioresponsive bifunctional dental composites against mature microcosm biofilms derived from subgingival plaque samples. The designed formulations contain 2 bioactive agents: dimethylaminohexadecyl methacrylate (DMAHDM) at 3 to 5 wt.% and 20 wt.% nanosized amorphous calcium phosphate (NACP) in a base resin. Composites with no DMAHDM and NACP were used as controls. The newly formulated 5% DMAHDM–20% NACP composite was analyzed by micro-Raman spectroscopy and transmission electron microscopy. The wettability and surface-free energy were also assessed. The inhibitory effect on the in vitro biofilm growth and the 16S rRNA gene sequencing of survival bacterial colonies derived from the composites were analyzed. Whole-biofilm metabolic activity, polysaccharide production, and live/dead images of the biofilm grown over the composites complement the microbiological assays. Overall, the designed formulations had higher contact angles with water and lower surface-free energy compared to the commercial control. The DMAHDM-NACP composites significantly inhibited the growth of total microorganisms, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Aggregatibacter actinomycetemcomitans, and Fusobacterium nucleatum by 3 to 5-log ( P < 0.001). For the colony isolates from control composites, the composition was typically dominated by the genera Veillonella, Fusobacterium, Streptococcus, Eikenella, and Leptotrichia, while Fusobacterium and Veillonella dominated the 5% DMAHDM–20% NACP composites. The DMAHDM-NACP composites contributed to over 80% of reduction in metabolic and polysaccharide activity. The suppression effect on plaque biofilms suggested that DMAHDM-NACP composites might be used as a bioactive material for cervical restorations. These results may propose an exciting path to prevent biofilm growth and improve dental composite restorations’ life span.

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