Comparison of biodegradation kinetic parameters for naphthalene in batch and sand column systems by pseudomonas putida

Abstract

Kinetic parameters for the degradation of naphthalene by Pseudomonas putida ( ATCC 17484) were estimated in both batch and column assays, in order to evaluate the role of flow and cell attachment on biodegradation rates. Suspended cells and cells attached to Ottawa sand were used under a variety of biomass levels, column flow‐rates, and substrate concentrations. In batch systems, degradation followed zero order kinetics across the entire concentration range, while the columns exhibited decreased rates at concentrations less than 100 (μg/L), describable by Michaelis‐Menten kinetics. This is reflected in elevated values of the half‐saturation constant, Ks, in columns. We offer the explanation that this may have resulted from reactive heterogeneity within the porous media, imposing a distribution of length‐scales for transfer of substrate to the cell surfaces. Well‐mixed batch systems are expected to have both shorter and more uniform transfer distances. When kinetic parameters obtained in batch system are used for prediction of degradation in columns, at least two factors—exposed reduction of exposed cell surface are a and heterogeneity of cell distribution—will likely reduce overall column degradation rates.

Kinetics of microbial sulfate reduction in estuarine sediments

“…A similar effect is not observed at Rattekaai, however. Flow-through experiments with intact sediments from Appels and Waarde may experience a higher degree of what Park et al (2001) refer to as reactive heterogeneity: all flow paths do not necessarily sample the same biomass and therefore do not experience the same reaction history. The lack of mass transfer limitation in Rattekaai sediment may be due to the much higher SRB densities and higher sediment porosities, as these would reduce the transfer distances of dissolved substrates from the pore water medium to particle-bound SRB cells.…”

“…6B highlight the ambiguities associated with comparing kinetic parameters obtained using different experimental approaches (Park et al, 2001). In sediment slurry experiments, microbial aggregates as well as particle-bound biofilms are disrupted (Marxsen and Fiebig, 1993), which results in an increase of free-living cells over particle-bound cells.…”

Mass Transfer and Bioremediation of Naphthalene and Methyl Naphthalenes in Baffled and Bead Mill Bioreactors

“…The batch growth kinetics on naphthalene and 2-methylnaphthalene were simulated using fi rst order growth kinetics assuming that PAHs were the limiting substrates. First order kinetics is a reasonable assumption for the growth of P. putida on naphthalene since it has been shown that the saturation constant is considerably less than 1 mg/l (Park et al, 2001;Alshafi e and Ghoshal, 2003). However, the removal rates of the substrates (and therefore the growth rate of the bacteria) were limited by the maximum mass transfer rates of the substrates from the solid particles to the aqueous media, which differed for each type of bioreactor and each substrate.…”

Remediation of PAHs contaminated soil by extraction using subcritical water

“…Anekpankul and Goto [31] suggested that extraction is controlled by intraparticle diffusion which is related to water flow rate. Therefore, it is expected that a high flow rate reduces external mass transfer resistance and increases extraction efficiency [32]. In this study, several flow rate conditions, 0.5, 1.0, 1.5, and 2.0 mL/min, were examined at the constant temperature of 250 8C and extraction time of 30 min ( Table 4).…”