Biodegradation Of Naphthalene Research Articles

Assessment of the performance of SMFCs in the bioremediation of PAHs in contaminated marine sediments under different redox conditions and analysis of the associated microbial communities

The biodegradation of naphthalene, 2-methylnaphthalene and phenanthrene was evaluated in marine sediment microbial fuel cells (SMFCs) under different biodegradation conditions, including sulfate reduction as a major biodegradation pathway, employment of anode as terminal electron acceptor (TEA) under inhibited sulfate reducing bacteria activity, and combined sulfate and anode usage as electron acceptors. A significant removal of naphthalene and 2-methylnaphthalene was observed at early stages of incubation in all treatments and was attributed to their high volatility. In the case of phenanthrene, a significant removal (93.83±1.68%) was measured in the closed circuit SMFCs with the anode acting as the main TEA and under combined anode and sulfate reduction conditions (88.51±1.3%). A much lower removal (40.37±3.24%) was achieved in the open circuit SMFCs operating with sulfate reduction as a major biodegradation pathway. Analysis of the anodic bacterial community using 16S rRNA gene pyrosequencing revealed the enrichment of genera with potential exoelectrogenic capability, namely Geoalkalibacter and Desulfuromonas, on the anode of the closed circuit SMFCs under inhibited SRB activity, while they were not detected on the anode of open circuit SMFCs. These results demonstrate the role of the anode in enhancing PAHs biodegradation in contaminated marine sediments and suggest a higher system efficiency in the absence of competition between microbial redox processes (under SRB inhibition), namely due to the anode enrichment with exoelectrogenic bacteria, which is a more energetically favorable mechanism for PAHs oxidation than sulfate.

Isolation and characterization of naphthalene biodegrading Methylobacterium radiotolerans bacterium from the eastern coastline of the Kingdom of Saudi Arabia

Abstract Bioremediation is based on microorganisms able to use pollutants either as a source of carbon or in co-metabolism, and is a promising strategy in cleaning the environment. Using soil contaminated with petroleum products from an industrial area in Saudi Arabia (Jubail), and after enrichment with the polycyclic aromatic hydrocarbon (PAH) naphthalene, a Methylobacterium radiotolerans strain (N7A0) was isolated that can grow in the presence of naphthalene as the sole source of carbon. M. radiotolerans is known to be resistant to gamma radiation, and this is the first documented report of a strain of this bacterium using a PAH as the sole source of carbon. The commonly reported Pseudomonas aeruginosa (strain N7B1) that biodegrades naphthalene was also identified, and gas chromatography analyses have shown that the biodegradation of naphthalene by M. radiotolerans and P. aeruginosa did follow both the salicylate and phthalate pathways.

Biological Degradation of Heterocyclic Aromatic Hydrocarbons with Naphthalene-Enriched Consortium: Substrate Interaction Studies and Fate of Metabolites

The current work has attempted to understand the substrate interaction between aromatic compounds of similar and divergent nature and the significance of their interactions on the biodegradation kinetics of compounds in a mixture. The chosen representative compounds for the present study are pyridine, quinoline, benzothiophene, benzofuran and naphthalene. Biodegradation studies were performed on binary, ternary, and multipollutant systems. Benzothiophene and benzofuran were the most persistent contaminants and they exhibit a significant inhibitory effect on the biodegradation of other co-contaminants, especially pyridine. The effects of different NSO compounds on naphthalene biodegradation and vice versa were also investigated. The presence of naphthalene (50mg/L) enhanced the rate of biodegradation of both benzothiophene (50mg/L) and benzofuran (50mg/L) by 40.4 and 23.91%, respectively. Distinct variation in composition and biodegradability of transition metabolites were observed during multisubstrate degradation. The presence of benzothiophene and benzofuran also significantly inhibited the degradation of prominent metabolic intermediates resulting in their accumulation in the system for a very longer period of time. An attempt was also made to simulate the biodegradation kinetics in a multipollutant system using a mathematical model. The multisubstrate model predicted the behavior of these systems satisfactorily.

Enrichment and identification of naphthalene-degrading bacteria from the Persian Gulf

Naphthalene is a ubiquitous pollutant of the marine environment, and naphthalene biodegradation has been receiving constant scientific consideration. For cleanup of aromatic contaminated sites, bioremediation methods are considered as economical and safe approaches for the marine environment. The aims of this research are isolation and characterization of naphthalene-degrading bacteria from some marine samples of the Persian Gulf. Fifty four naphthalene-degrading bacteria were isolated from marine samples (sediment and seawater) that are enriched in ONR7a medium with naphthalene as the only carbon source. Some screening tests such as growth at high concentration of naphthalene, bioemulsifier production and surface hydrophobicity were done to select the best and prevalent strains for naphthalene degradation. Determination of the nucleotide sequence of the gene encoding for 16S rRNA shows that these isolated strains belong to these genera: Shewanella, Salegentibacter, Halomonas, Marinobacter, Oceanicola, Idiomarina and Thalassospira. These strains can degrade half of the percentage of naphthalene in 10days of incubation. This research is the first report on isolation of these genera from the Persian Gulf as naphthalene-degrader.

Engineering of a silica encapsulation platform for hydrocarbon degradation using Pseudomonas sp. NCIB 9816-4.

Industrial application of encapsulated bacteria for biodegradation of hydrocarbons in water requires mechanically stable materials. A silica gel encapsulation method was optimized for Pseudomonas sp. NCIB 9816-4, a bacterium that degrades more than 100 aromatic hydrocarbons. The design process focused on three aspects: (i) mechanical property enhancement; (ii) gel cytocompatibility; and (iii) reduction of the diffusion barrier in the gel. Mechanical testing indicated that the compressive strength at failure (σf ) and elastic modulus (E) changed linearly with the amount of silicon alkoxide used in the gel composition. Measurement of naphthalene biodegradation by encapsulated cells indicated that the gel maintained cytocompatibility at lower levels of alkoxide. However, significant loss in activity was observed due to methanol formation during hydrolysis at high alkoxide concentrations, as measured by FTIR spectroscopy. The silica gel with the highest amount of alkoxide (without toxicity from methanol) had a biodegradation rate of 285 ± 42 nmol/L-s, σf = 652 ± 88 kPa, and E = 15.8 ± 2.0 MPa. Biodegradation was sustained for 1 month before it dropped below 20% of the initial rate. In order to improve the diffusion through the gel, polyvinyl alcohol (PVA) was used as a porogen and resulted in a 48 ± 19% enhancement in biodegradation, but it impacted the mechanical properties negatively. This is the first report studying how the silica composition affects biodegradation of naphthalene by Pseudomonas sp. NCIB 9816-4 and establishes a foundation for future studies of aromatic hydrocarbon biodegradation for industrial application.

An integrated biodegradation and nano-oxidation used for the remediation of naphthalene from aqueous solution

The remediation of toxic persistent organic contaminants in the environment has raised a need for effective cleanup methods. In this study, an integrated remediation technique based on biodegradation of naphthalene using Bacillus fusiformis and Fenton oxidation of their degraded metabolites using nanoscale zero-valent iron (nZVI). A 99.0% naphthalene was biodegraded by B. fusiformis in 96h, while only 59.4% chemical oxygen demand (COD) was removed, indicating that the degraded metabolites existed in solution. To further degrade the metabolites, nanoscale zero-valent iron (nZVI) was used as heterogeneous catalyst for Fenton-like oxidation of the metabolites after biodegradation lasting 40h. Results showed that the total the removal COD increased from 36.4% to 91.6% at pH 3.0, 1.0gL−1 nZVI, 10.0mML−1 H2O2 and temperature of 35°C. Scanning electron microscopy (SEM) showed the aggregation and corrosion of nZVI. X-ray diffraction (XRD) confirmed the existence of Fe0 and the presence of iron oxide (Fe(II)) and iron oxohydroxide (Fe(III)). A possible degradation pathway was proposed since two naphthalene metabolites (1-Naphthalenol and 1,4-Naphthalenedione) were detected by GC–MS.

Biodegradation of naphthalene using Pseudomonas aeruginosa by up flow anoxic-aerobic continuous flow combined bioreactor.

BackgroundNaphthalene is a poly aromatic hydrocarbon (PAH) present in many sediment-water systems. The aim of this study was to evaluate the applicability of an anoxic/aerobic system for the biological treatment of water polluted by naphthalene by Pseudomonas aeruginosa PTCC 1707 to utilize naphthalene. The naphthalene elimination from wastewater was determined in anoxic–aerobic continuous flow combined bioreactor under continuously oxic and anoxic conditions. Experiments were conducted in continues mode, and naphthalene was administered in consecutive spike doses. Then Pseudomonas aeruginosa bacteria suspension with a specific turbidity (0.5-10 NTU) was prepared from growing bacteria on R2A medium and injected to reactor.FindingsAt naphthalene concentration = 0.5-20 mg/L, 33–65.5% naphthalene removal efficiencies were observed. Mean COD removal efficiency in solid retention times of 2, 4, 6, and 8 days was 82.7, 92.45, 95.97 and 96.1%, respectively. Naphthalene removal efficiency by bacterium pseudomonas at pH 8 was 96% and at pH 4, 5.5, 7 and 9.5, 68, 80, 90 and 85%, respectively. As the initial concentration of naphthalene increased from 0.5 to 20 mg/L, the remaining concentration of naphthalene decreased from 33.4% to 65.5% after 3 days.ConclusionBased on experimental results, it was determined that this process can effectively reduce naphthalene under optimal conditions and this method can be used for the removal of similar compounds.

The influence of sorption on polyaromatic hydrocarbon biodegradation in the presence of modified nonionic surfactant organoclays

This study examined naphthalene (NAP) biodegradation in the presence of organoclays (Ca-Mon) modified by two nonionic surfactants (TX-100 and Brij 35). The nonionic surfactants are adsorbed onto the clay and this provides extra organic matter, which then generates a partition effect that affects NAP biodegradation. NAP biodegradation was found to be affected by the presence of monomer (MN) or micelle (CMC) surfactant-modified organoclays. The pseudo first-order rate constants for NAP biodegradation were as follows: NAP-Brij35-MN > NAP-Brij35-CMC > NAP > NAP-TX-100-MN > NAP-TX-100-CMC, exactly opposite to the soil organic carbon–water partitioning coefficient (koc) values for NAP in the presence of different nonionic surfactants. The bacterial community and physiological characteristics of PAH biodegradation were different between the free-living bacteria and the particle-attached bacteria and was not associated with the surfactant used. The dominant free-living bacteria involved in NAP biodegradation were Brevundimonas diminuta, Caulobacter spp., Mycoplana bullata, Acidovorax spp. and Pseudomonas aeruginosa. Community-level physiological profiling showed significant differences between free-living bacteria and particle-attached bacteria. Significant extracellular enzyme activities, such as esterases and phosphatases, were associated with the TX-100-MN/CMC modified organoclays. Practically, the results suggest that Brij 35 MN-modified organoclay is the most suitable substrate when using a nonionic surfactant for NAP bioremediation.

The role of mineral phosphorus compounds in naphthalene biodegradation by Pseudomonas putida

The role of mineral phosphorus compounds in naphthalene biodegradation by Pseudomonas putida

Genetic determinants involved in the biodegradation of naphthalene and phenanthrene in Pseudomonas aeruginosa PAO1.

Pseudomonas sp. are predominant isolates of degradation-competent strains while very few studies have explored the degradation-related genes and pathways in most of the degrading strains. P. aeruginosa PAO1 was found capable of degrading naphthalene and phenanthrene efficiently. In order to investigate the degradation-related genes of naphthalene and phenanthrene in P. aeruginosa PAO1, a random promoter library of about 5760 strains was constructed. Thirty-two clones for differentially expressed promoters were obtained by screening in the presence of sub-inhibitory concentration of naphthalene and phenanthrene. Among them, 13 genes were up-regulated and 15 were down-regulated in the presence of naphthalene as well as phenanthrene. The four remaining genes have different regulation tendencies by naphthalene or phenanthrene. By comparing the growth between the wild type and mutants as well as the complementations, the roles of seven selected up-regulated genes on naphthalene and phenanthrene degradation were investigated. Five of the seven selected up-regulated genes, like PA2666 and PA4780, were found playing key roles on the degradation in P. aeruginosa PAO1. Also, the results imply that these genes participate in the overlapping part of naphthalene and phenanthrene degradation pathways in PAO1. Results in the article offer the convenience quick method and platform for searching degradation-related genes. It also laid a foundation for understanding of the role of the regulated genes.

Evidence of polycyclic aromatic hydrocarbon biodegradation in a contaminated aquifer by combined application of in situ and laboratory microcosms using 13C-labelled target compounds

The number of approaches to evaluate the biodegradation of polycyclic aromatic hydrocarbons (PAHs) within contaminated aquifers is limited. Here, we demonstrate the applicability of a novel method based on the combination of in situ and laboratory microcosms using 13C-labelled PAHs as tracer compounds.The biodegradation of four PAHs (naphthalene, fluorene, phenanthrene, and acenaphthene) was investigated in an oxic aquifer at the site of a former gas plant. In situ biodegradation of naphthalene and fluorene was demonstrated using in situ microcosms (BACTRAP®s). BACTRAP®s amended with either [13C6]-naphthalene or [13C5/13C6]-fluorene (50:50) were incubated for a period of over two months in two groundwater wells located at the contaminant source and plume fringe, respectively. Amino acids extracted from BACTRAP®-grown cells showed significant 13C-enrichments with 13C-fractions of up to 30.4% for naphthalene and 3.8% for fluorene, thus providing evidence for the in situ biodegradation and assimilation of those PAHs at the field site. To quantify the mineralisation of PAHs, laboratory microcosms were set up with BACTRAP®-grown cells and groundwater. Naphthalene, fluorene, phenanthrene, or acenaphthene were added as 13C-labelled substrates. 13C-enrichment of the produced CO2 revealed mineralisation of between 5.9% and 19.7% for fluorene, between 11.1% and 35.1% for acenaphthene, between 14.2% and 33.1% for phenanthrene, and up to 37.0% for naphthalene over a period of 62 days. Observed PAH mineralisation rates ranged between 17 μg L−1 d−1 and 1639 μg L−1 d−1.The novel approach combining in situ and laboratory microcosms allowed a comprehensive evaluation of PAH biodegradation at the investigated field site, revealing the method's potential for the assessment of PAH degradation within contaminated aquifers.

Biosurfactant-Mediated Biodegradation of Polycyclic Aromatic Hydrocarbons—Naphthalene

ABSTRACTThe present study is aimed at the naphthalene degradation with and without biosurfactant produced from Pseudomonas aeruginosa isolated from oil-contaminated soil. The present study was carried out to isolate the bacterial strains for the naphthalene degradation and also for biosurfactant production. The isolated strains were screened for their ability to degrade the naphthalene by the methods of optimum growth rate test and for the production of biosurfactants by cetyltrimethylammonium bromide, blood agar medium, and thin-layer chromatography. The present study also focused on the effect of biosurfactant for the degradation of naphthalene by isolate-1. Two bacterial strains were isolated and screened, one for biodegradation and another for biosurfactant production. The second organism was identified as Pseudomonas aeruginosa by 16S rRNA analysis. The purified biosurfactant reduces the surface tension of water and also forms stable emulsification with hexadecane and kerosene. The end product of naphthalene degradation was estimated as salicylic acid equivalent by spectrophotometric method. The results demonstrated that Pseudomonas aeruginosa has the potential to produce biosurfactant, which enhances the biodegradation of naphthalene. The study reflects the potential use of biosurfactants for an effective bioremediation in the management of contaminated soils.

Biodegradation of naphthalene using a functional biomaterial based on immobilized Bacillus fusiformis (BFN)

The degradation of naphthalene using immobilized Bacillus fusiformis (BFN) strain on alginate–polyvinyl alcohol (PVA)–clays bead was much higher than that of using a freely suspended BFN strain. This was due to the beads facilitating biodegradation by enhancing concentration of naphthalene using the beads as an adsorbent in the cells’ vicinity. This was confirmed by the kinetics of naphthalene on the beads, where its adsorption onto the beads was confirmed by pseudo-second-order kinetics. The biodegradation of naphthalene fitted well to the first-order rate model. More than 99.7% of naphthalene which was removed within 12h, contained bentonite 2% (w/v), PVA 12% (w/v), alginate 0.3% (w/v) and 10% (v/v) initial biomass loading. Scanning electron microscopy (SEM) of the beads showed that B. fusiformis was evenly distributed within them. Storage stability and reusability results revealed that the ability to degrade naphthalene using beads with immobilized cells remained stable after storage at 4°C for 35 days and being reused 8 times (12 days), respectively. Furthermore the naphthalene degradation rate of immobilized cells was maintained (94.3%) at the eighth cycle.

Naphthalene degradation in the presence of natural–synthetic surfactants mixture by mixed bacterial cultures

Biosurfactants are the most probable future candidates to substitute the synthetic surfactants in the area of applied surfactants research. Herein we focused on the natural plant based surfactant (Reetha) extracted from the pod of Sapindus mukorossi and its substitution potential with synthetic surfactants (TX-100, CTAB, and SDBS). Mixture of Reetha and synthetic surfactants was tested for the biodegradation of naphthalene. The biodegradation efficiency of surfactants against two mixed bacterial cultures viz., defined or known culture (KC) and mining waste water culture (WWC) was investigated. Addition of Reetha in the presence of ionic surfactants has increased the degradation efficiency of naphthalene. Degradation rate constants (K) and zeta potential assessments revealed that WWC has more potential than KC with surfactant mixtures (especially CTAB-Reetha). The highest degradation potential (K value=0.31) was identified with WWC having 0.5mol fraction of Reetha in CTAB-Reetha combination. The results suggested that the use of Reetha in combination with ionic surfactants has an enormous potential to make the biodegradation process more eco-friendly and economical by decreasing the surfactant cost.

Laboratory-scale in situ bioremediation in heterogeneous porous media: Biokinetics-limited scenario

Subsurface heterogeneities influence interfacial mass-transfer processes and affect the application of in situ bioremediation by impacting the availability of substrates to the microorganisms. However, for difficult-to-degrade compounds, and/or cases with inhibitory biodegradation conditions, slow biokinetics may also limit the overall bioremediation rate, or be as limiting as mass-transfer processes. In this work, a quantitative framework based on a set of dimensionless coefficients was used to capture the effects of the competing interfacial and biokinetic processes and define the overall rate-limiting process. An integrated numerical modeling and experimental approach was used to evaluate application of the quantitative framework for a scenario in which slow-biokinetics limited the overall bioremediation rate of a polycyclic aromatic hydrocarbon (naphthalene). Numerical modeling was conducted to simulate the groundwater flow and naphthalene transport and verify the system parameters, which were used in the quantitative framework application. The experiments examined the movement and biodegradation of naphthalene in a saturated, heterogeneous intermediate-scale flow cell with two layers of contrasting hydraulic conductivities. These experiments were conducted in two phases: Phase I, simulating an inhibited slow biodegradation; and Phase II, simulating an engineered bioremediation, with system perturbations selected to enhance the slow biodegradation rate. In Phase II, two engineered perturbations to the system were selected to examine their ability to enhance in situ biodegradation. In the first perturbation, nitrogen and phosphorus in excess of the required stoichiometric amounts were spiked into the influent solution to mimic a common remedial action taken in the field. The results showed that this perturbation had a moderate positive impact, consistent with slow biokinetics being the overall rate-limiting process. However, the second perturbation, which was to alleviate inhibition and increase the biodegradation rate, enhanced the overall biotransformation rate to a greater degree.

<sup>13</sup>C/<sup>12</sup>C Isotope Fractionation during Aerobic and Anaerobic Biodegradation of Naphthalene

Microcosm experiments were conducted to determine the fractionation of stable carbon isotopes during biodegradation of naphthalene. The microcosms were performed under aerobic conditions, anaerobic (amended with sulfate, amended with nitrate and with no amendments) and sterile controls. The liquid phase was analyzed to determine naphthalene concentration and stable carbon isotope signature. Aerobic microcosm showed that naphthalene degraded aerobically within 60 hours. The δ13C increased from -25.5‰ to -25.1‰ (enrichment of 0.4‰ ± 0.08‰) in a single sample in which 95% of the naphthalene was biodegraded. Anaerobic microcosms show that after 288 days, the microcosms with no amendments, amended with nitrate and amended with sulfate had consumed respectively 30%, 50% and 60% of naphthalene on average, compared to control microcosms. Under the denitrifying conditions, the δ13C of naphthalene increased from -25.2‰ to -23.9‰ (enrichment of 1.3‰ ± 0.3‰) after a 95% of naphthalene biodegradation. For the unamended microcosms, a slight enrichment on δ13C napththalene was detected, from -25.2‰ to -24.5‰ (enrichment of 0.7‰ ± 0.3‰) after a biodegradation of approximately 65% of naphthalene (after 288 days). For sulfate reducing microcosms, no significant changes were detected on the δ13C during naphthalene biodegradation.

Use of a packed-bed airlift reactor with net draft tube to study kinetics of naphthalene degradation by Ralstonia eutropha

Biodegradation of naphthalene by Ralstonia eutropha (also known as Cupriavidus necator) in a packed-bed airlift reactor with net draft tube (PBALR-nd) was studied; the Kissiris pieces were the packing material. The reactor hydrodynamics has been characterized under abiotic conditions and the dependencies of the superficial gas velocity (U G) on the gas holdup (εG), liquid mixing time, and mass transfer coefficient were determined. The improving role of the net draft tube in this small column reactor (height 42 cm, ID 5 cm) was confirmed. The flow regime was described using the εG α U G (n) expression, and bubbly flow was observed in PBALR-nd at U G < 2.83 cm/s. In the second step of the present work, the kinetics of biodegradation was modeled using the Haldane and Aiba equations. The fitting of the experimental results to the models were done according to the nonlinear least square regression technique. The biokinetic constants (q m, K s, and K i) were estimated and q m as the specific biodegradation rate was equaled to 0.415 and 0.24 mgnaph./mgcell h for the Haldane and Aiba equations, respectively. The goodness of fit reported as R (2) and root-mean-square error (RMSE) showed the adequate fitness of the Haldane and Aiba models in predicting naphthalene biodegradation kinetics. On the basis of the HPLC results, a hypothetical pathway for the biodegradation was presented.

Use of [13C]/[12C] ratios as an indicator of the role of microorganisms in protection of plants from the phytotoxic action of naphthalene

Using molecular and isotopic mass spectrometry, we investigated the toxic effect of naphthalene as a representative of polycyclic aromatic hydrocarbons (PAHs) on plants growing under sterile conditions and plants inoculated with microorganisms capable and incapable of naphthalene degradation. Tobacco plants of the Samsun variety were grown in a closed gas-nutrient system on a mineral medium with sucrose as a carbon source. Naphthalene used as a toxicant at a concentration of 5.2 × 10−4% contained 13C isotope whose amount was characterized by the value δ13C = +281.4 ± 0.6‰ relative to the PDB standard and differed from that of sucrose, the main source of carbon (δ13C = −12.0 ± 0.1‰). Degradation of naphthalene was determined by the inclusion of its carbon in metabolic CO2 and plant tissues (the root, stem, leaves). The effect of naphthalene on plants was indicated by the rates of O2 production and CO2 uptake during the light period as compared with the dark period of exposure. A decrease of the toxic effect of naphthalene on plants was observed only at the inoculation of plants with Pseudomonas aureofaciens BS1393 rhizosphere bacteria bearing plasmid pBS216, which controls the naphthalene biodegradation ability. The occurrence of other heterotrophic microorganisms incapable of naphthalene degradation had no similar protective effect.

Biodegradation of naphthalene in the oil refinery wastewater by enriched activated sludge

The main purpose of this paper is to study naphthalene (NAP) biodegradation by acclimated activated sludge, employing the culture-enrichment method in a continuous flow bioreactor of the wastewater treatment process. The effects of various COD loadings and influent flow rates of an artificial wastewater containing 15 mg l−1 NAP on the biodegradation rates of the activated sludge will be investigated, in order to determine the biodegradation kinetics and minimum mean cell residence time of the activated sludge. From the experimental results, it was found that the resulting enriched activated sludge follows the growth rate of the Monod type and can biodegrade those COD and NAP loadings in the influents efficiently, and its bio-treatment efficiency on NAPs increases with the decrease of influent flow rate. The sludge volume index (SVI) of the resulting enriched activated sludge meets the design value required by the convectional activated sludge process for the treatment of wastewater.

Models for the Biodegradation Kinetics of Naphthalene by Ralstonia Eutropha

Biodegradation of naphthalene (naph.) by a pure culture of Ralstonia eutropha was studied. Dissolution of naph. in aqueous solution was provided by using Tween-80 nonionic surfactant. By developing the solubility curve, the molar solubility ratio (MSR) was determined (0.8081). The effects of Tween-80, initial-pH, and naph. concentration on the R. eutropha growth and its naph. degradation capability were investigated. Degradation of naph. at 50 mg/L was complete within 52 h in the presence of 1.6 mM Tween-80 at pH 7. Haldane, Webb, Aiba, and Edwards, as the growth inhibitory kinetic models, were used to mathematically describe the inhibitory characteristic of naphthalene and the results were evaluated using nonlinear regression technique. The values of root mean square error (RMSE) and the correlation coefficient (R2) showed appropriateness of approach taken in the present study (RMSE≈ 3×10−3, R2≈ 0.99). Importance of the mechanistic view of these types of mathematical models has been emphasized.