Biodegradation by Bacteria Immobilised on Celite Particles

Caunt, P.; Chase, Howard A.

doi:10.1038/nbt0688-721

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…This chemicallyinert matrix consists of diatomaceous earth diatoms which are broken up and then recalcined to give controlled pore sizes and particle diameters. The chemistry of microbial adhesion to surfaces is as yet not very well understood; however, previous work has shown that Celite particles are suitable for immobilizing a wide range of microbes (Caunt and Chase, 1988;Wang et al, 1984;Robinson et al, 1985;Baker et al, 1984). The Celite particles were sieved on a mechanical vibrator for 20 minutes, and the size fraction between 750 and 11 80 x m was kept and used herein.…”

Section: Matrix For Cell Immobilizationmentioning

confidence: 96%

Modeling phenol degradation in a fluidized‐bed bioreactor

1989

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A study was made of phenol degradation by bacteria immobilized onto particles of calcined diatomaceous earth in a draft-tube, threephase fluidized-bed reactor.A mathematical model is used to describe simultaneous diffusion and reaction of oxygen and phenol in the reactor. Kinetic parameters for the growth of nonsupported cells were obtained in batch and chemostat experiments. Liquid-solid mass transfer coefficients were determined experimentally and showed good agreement with literature values for conventional three-phase fluidized beds. Experimental steady-state degradation data were used to calculate biofilm substrate diffusivities. These were found to decrease as the biofilm density increased.The transition from phenol to oxygen-limiting biofilm kinetics predicted by the model was shown to exist experimentally. A critical ratio of phenol/ dissolved oxygen concentration was found at which this transition occurred. This provides a criterion for establishing whether increased aeration will increase the volumetric degradation rate. IntroductionBiological films are commonly used in waste water treatment (trickle filter, rotating disk) as they provide several advantages over freely-suspended cell systems. These include high biomass concentration, increased resistance to toxic shock loadings (Parkin and Spence, 1984), and higher volumetric throughputs due to the independence of cell growth rate from reactor dilution rate. Holladay et al. (1978) and Denac and Dunn (1987) have compared packed-vs. fluidized-bed biofilm reactors containing immobilized microorganisms and found the fluidized-bed reactor to be more efficient in terms of volumetric degradation capacity. have showed that the performance for phenol degradation of a three-phase fluidized-bed reactor fitted with a draft tube to promote the internal circulation of the liquid and solid phases is superior to that of a conventional three-phase fluidized bed.In this work a three-phase fluidized-bed reactor (FBR) with an internal draft tube is used to study the biodegradation of phenol, mass transfer from the bulk liquid to the bioparticle, and diffusion and reaction within the bioparticle. An ion exchange resin is used to determine the liquid-solid mass transfer coefficient. A mixed microbial culture attaches itself to the solid sup- Previous workers in this field Worden and Donaldson, 1987) have proposed models describing mass transfer and reaction in these types of reactors, but the range of experimental validation of these models is limited to the case when one substrate controls the reaction rate. In the present work, conditions are varied so that the limiting substrate undergoes a transition from phenol to oxygen. This allows the verification of the two-substrate-limiting kinetic expression and establishes a criterion for determining whether the degradation rate is oxygen-or phenol-limited. Mathematical ModelA model describing the microbial degradation of phenol by immobilized bacteria was developed along similar lines to the one employed by . Liquid-solid mass...

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Section: Matrix For Cell Immobilizationmentioning

confidence: 96%

Modeling phenol degradation in a fluidized‐bed bioreactor

1989

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“…In an effort to overcome factors known to inhibit inoculation procedures forbioremediation applications, we have developed a variety of microbial encapsulation and cell immobilization technologies (Lin et al, 1992;Lin et al, 1991) similar to some of those previously described (Caunt and Chase, 1988;European Patent Office, 1989;Stormo and Crawford, 1992). Data from in-house laboratory studies, using bacteria active towards HMW PAHs, have shown that these technologies provide an effective means of inoculant storage and distribution (fin et al, unpublished data).…”

Section: Applkatlon Of Cell Encapstthation Tecbnolohes To Bioremediationmentioning

confidence: 97%

Recent developments in cleanup technologies

Simon¹,

McCulloch²

1993

Remediation Journal

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“…Ideally, suitable biocarriers for immobilization of microorganisms should be nontoxic and should provide a rough, irregular surface. The matrix should be hydrophilic (23) and porous (17); these properties have been shown by others to promote the adherence and proliferation of microorganisms (2,12,(14)(15)(16)19). A porous structure permits internal colonization that serves as a biomass reserve for recolonization of bioreactors after severe system shocks (9-11).…”

mentioning

confidence: 99%

Characterization of Inorganic Biocarriers That Moderate System Upsets during Fixed-Film Biotreatment Processes

Durham

Marshall

Miller

et al. 1994

Appl Environ Microbiol

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Inorganic matrices were developed for fixed-film bioreactors affording protection to microorganisms and preventing loss of bioreactor productivity during system upsets. These biocarriers, designated Type-Z, contain ion-exchange properties and possess high porosity and a high level of surface area, which provide a suitable medium for microbial colonization. Viable cell populations of 10 9 /g were attainable, and scanning electron micrographs revealed extensive external colonization and moderate internal colonization with aerobic microorganisms. Laboratory-scale bioreactors were established with various biocarriers and colonized with Pseudomonas aeruginosa , and comparative studies were performed. The data indicated that bioreactors containing the Type-Z biocarriers were more proficient at removing phenol (1,000 ppm) than bioreactors established with Flexirings (plastic) and Celite R635 (diatomaceous earth) biocarriers. More significantly, these biocarriers were shown to moderate system upsets that affect operation of full-scale biotreatment processes. For example, subjecting the Type-Z bioreactor to an influent phenol feed at pH 2 for periods of 24 h did not decrease the effluent pH or reactor performance. In contrast, bioreactors containing either Celite or Flexirings demonstrated an effluent pH drop to ∼2.5 and a reduction in reactor performance by 75 to 82%. The Celite reactor recovered after 5 days, whereas the bioreactors containing Flexirings did not recover. Similar advantages were noted during either nutrient or oxygen deprivation experiments as well as alkali and organic system shocks. The available data suggest that Type-Z biocarriers represent an immobilization medium that provides an amenable environment for microbial growth and has the potential for improving the reliability of fixed-film biotreatment processes.

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Biodegradation by Bacteria Immobilised on Celite Particles

Cited by 9 publications

References 8 publications

Modeling phenol degradation in a fluidized‐bed bioreactor

Modeling phenol degradation in a fluidized‐bed bioreactor

Recent developments in cleanup technologies

Characterization of Inorganic Biocarriers That Moderate System Upsets during Fixed-Film Biotreatment Processes

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