Simple prediction of oxygen penetration depth in biofilms for wastewater treatment

Hibiya, Kazuaki; Nagai, Jun; Tsuneda, Satoshi; Hirata, Akira

doi:10.1016/j.bej.2003.10.003

Cited by 46 publications

(28 citation statements)

References 29 publications

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“…strain Y4I bacteria once the biofilm reaches a threshold concentration or level of maturity. This may be a mechanism to control the biofilm structure such that it is maintained at an optimal state, particularly with respect to microscale oxygen gradients, which have been shown to influence bacterial activities within biofilms (61,62). Indeed, the reduced form of indigoidine (leucoindigoidine) is predicted to be the antimicrobial form of the molecule (28,63,64) and it spontaneously oxidizes to the nonactive form in the presence of atmospheric oxygen (28,63,64).…”

Section: Discussionmentioning

confidence: 99%

Phaeobacter sp. Strain Y4I Utilizes Two Separate Cell-to-Cell Communication Systems To Regulate Production of the Antimicrobial Indigoidine

Cude

Prevatte

Hadden

et al. 2015

Appl Environ Microbiol

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The marine roseobacter Phaeobacter sp. strain Y4I synthesizes the blue antimicrobial secondary metabolite indigoidine when grown in a biofilm or on agar plates. Prior studies suggested that indigoidine production may be, in part, regulated by cell-to-cell communication systems. Phaeobacter sp. strain Y4I possesses two luxR and luxI homologous N-acyl-L-homoserine lactone (AHL)-mediated cell-to-cell communication systems, designated pgaRI and phaRI. We show here that Y4I produces two dominant AHLs, the novel monounsaturated N-(3-hydroxydodecenoyl)-L-homoserine lactone (3OHC 12:1 -HSL) and the relatively common N-octanoyl-L-homoserine lactone (C 8 -HSL), and provide evidence that they are synthesized by PhaI and PgaI, respectively. A Tn5 insertional mutation in either genetic locus results in the abolishment (pgaR::Tn5) or reduction (phaR::Tn5) of pigment production. Motility defects and denser biofilms were also observed in these mutant backgrounds, suggesting an overlap in the functional roles of these systems. Production of the AHLs occurs at distinct points during growth on an agar surface and was determined by isotope dilution high-performance liquid chromatography-tandem mass spectrometry (ID-HPLC-MS/MS) analysis. Within 2 h of surface inoculation, only 3OHC 12:1 -HSL was detected in agar extracts. As surface-attached cells became established (at ϳ10 h), the concentration of 3OHC 12:1 -HSL decreased, and the concentration of C 8 -HSL increased rapidly over 14 h. After longer (>24-h) establishment periods, the concentrations of the two AHLs increased to and stabilized at ϳ15 nM and ϳ600 nM for 3OHC 12:1 -HSL and C 8 -HSL, respectively. In contrast, the total amount of indigoidine increased steadily from undetectable to 642 M by 48 h. Gene expression profiles of the AHL and indigoidine synthases (pgaI, phaI, and igiD) were consistent with their metabolite profiles. These data provide evidence that pgaRI and phaRI play overlapping roles in the regulation of indigoidine biosynthesis, and it is postulated that this allows Phaeobacter sp. strain Y4I to coordinate production of indigoidine with different growth-phase-dependent physiologies. Bacteria are in constant competition for niches in the environment, and the ability to coordinate gene expression may provide a competitive advantage (1). Some bacteria are able to synchronize gene expression in a cell-density-dependent manner by sensing and responding to small diffusible molecules synthesized by individuals; in proteobacteria, members of the broadly distributed and chemically diverse class of N-acyl-L-homoserine lactones (AHLs) are among the best-characterized signaling molecules (2). Proteobacterial AHL synthases are fairly well conserved and form the LuxI protein family. Members of the LuxR protein family are cytoplasmic transcriptional regulators that can modulate gene expression, most typically when bound to the corresponding cognate AHL (3-7). It has been shown that luxI-luxR (luxIR) pairs are frequently colocalized within chromosomes and constitutively exp...

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Section: Discussionmentioning

confidence: 99%

Phaeobacter sp. Strain Y4I Utilizes Two Separate Cell-to-Cell Communication Systems To Regulate Production of the Antimicrobial Indigoidine

Cude

Prevatte

Hadden

et al. 2015

Appl Environ Microbiol

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show abstract

“…Dipper zones of biofilm serve as good conditions for denitrification or other processes requiring anaerobic or anoxic conditions. Hibiya et al (2004) noted that thanks to the isolation of interior space of thick biofilm from oxygen and autotrophs -heterotrophs competition, denitrification can be deemed successful.…”

mentioning

confidence: 99%

Effect of thickness of textile filter on organic compounds and nutrients removal efficiency at changeable wastewater surface level

Spychała

Lucyk²

2015

Nauka Przyr. Technol.

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Summary. The aim of the study was to identify the innovative filters' (textile filters for wastewater treatment) thickness impact on dissolved compounds removal efficiency and related: biomass concentration, hydraulic capacity and hydraulic retention time. The study was conducted on septic tank effluent (STE) which was filtered at changeable wastewater surface between 7 cm and 20 cm of height under hydrostatic pressure. The research was performed on filters of thickness: 1.8 mm, 3.6 mm and 7.2 mm. The thinner the filter layer, the lower the total solids content and the higher the hydraulic capacity. The thicker the filter layer, the higher the dissolved compounds removal efficiency. The most efficient in removal were the thickest (eight-layers) filters. The calculated hydraulic retention times were: 0.5, 1.1 and 3.3 h for two-, four-and eight-layer filters, respectively.

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“…Moreover, the maximum active thickness of the biofilm (L max ), calculated by Equation (10) for zero DO concentration on the wall barrier, is 237 mm, which is in close agreement with the reported values of average oxygen penetration depth in biofilms that are around 100-200 mm (De Beer et al, 1993). Hibiya et al (2004) measured oxygen concentration distributions in the biofilm by using an oxygen microelectrode, while they maintained a bulk oxygen concentration of 3 mg/L. They found that there was nonzero oxygen throughout the biofilm as long as it was less than 300 mm in thickness and that the oxygen penetration depth increased with increasing biofilm thickness.…”

Section: Model Validationmentioning

confidence: 98%

Effect of wall growth on the kinetic modeling of nitrite oxidation in a CSTR

Dokianakis

Kornaros

Lyberatos

2006

Biotechnol. Bioeng.

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A simple kinetic model was developed for describing nitrite oxidation by autotrophic aerobic nitrifiers in a continuous stirred tank reactor (CSTR), in which mixed (suspended and attached) growth conditions prevail. The CSTR system was operated under conditions of constant nitrite feed concentration and varying volumetric flow rates. Experimental data from steady-state conditions in the CSTR system and from batch experiments were used for the determination of the model's kinetic parameters. Model predictions were verified against experimental data obtained under transient operating conditions, when volumetric flow rate and nitrite feed concentration disturbances were imposed on the CSTR. The presented kinetic modeling procedure is quite simple and general and therefore can also be applied to other mixed growth biological systems.

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Simple prediction of oxygen penetration depth in biofilms for wastewater treatment

Cited by 46 publications

References 29 publications

Phaeobacter sp. Strain Y4I Utilizes Two Separate Cell-to-Cell Communication Systems To Regulate Production of the Antimicrobial Indigoidine

Phaeobacter sp. Strain Y4I Utilizes Two Separate Cell-to-Cell Communication Systems To Regulate Production of the Antimicrobial Indigoidine

Effect of thickness of textile filter on organic compounds and nutrients removal efficiency at changeable wastewater surface level

Effect of wall growth on the kinetic modeling of nitrite oxidation in a CSTR

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