Conditions For Biodegradation Research Articles

Identification and isolation of efficient phenol-degrading and heavy metal-resistant bacteria from seasonal catchments of the Lut Desert

ABSTRACT The present study was conducted to isolate and identify a phenol-degrading bacterial strain resistant to cadmium obtained from seasonal catchments of the Lut Desert, Iran. Additionally, optimal conditions affecting biological phenol degradation, including pH, temperature, salinity, and carbon-to-nitrogen ratio, were determined using the Taguchi method, and the ability of the purified strain to degrade phenol in different concentrations was investigated. Isolated bacterium strain Bacillus cereus LD-1, capable of phenol degradation and cadmium tolerance, could tolerate and degrade phenol up to a concentration of 1,500 mg/L. All optimized factors except carbon-to-nitrogen ratio had a significant effect on the rate of phenol biodegradation. Among the selected factors, based on the effect size, pH had the highest impact (10.02), followed by salinity (6.16), temperature (5.61), and C:N ratio (2.55) on phenol biodegradation. The optimal conditions for phenol biodegradation were determined as pH of 8, temperature of 30 °C, salinity of 0 g/L, and C:N ratio of 100:30. Under optimal conditions, 80.57% of phenol was decomposed by the LD-1 strain. Considering the high ability of the isolated strain for phenol degradation in the presence of 100 mg/L cadmium, LD-1 can be applied in the biological treatment of phenolic effluents contaminated with heavy metals.

Changes of wood surfaces treated with natural-based products – Structural and properties investigation

Preservative systems based on vegetable seed oils and natural waxes from renewable sources may confer protection to wood under exposure to various environmental conditions. These, as non-toxic substances, can form an environmentally friendly and efficient protective layer on the wood surfaces, with beneficial effects on their water resistance and dimensional stability. Thus, these natural coatings may hinder biodegradation of wood products to a certain degree. In present paper, softwood samples (from Abies alba fir tree species), prepared as dried discs (25 to 30 mm diameter, 8 to 10 mm thickness), were surface impregnated by dipping using vegetable oils, namely Asclepias syriaca seed oil, and soybean oil, respectively. Beeswax treatment was also applied for comparison purposes. Surface chemistry and morphology, biodegradation process under controlled and simulated natural conditions, and water sorption behavior of wood samples were investigated. Fourier Transform Infrared spectroscopy, X-ray diffraction, and scanning electron microscopy methods were used for investigation of surface changes in wood samples before and after impregnation with natural based products, as well as under biodegradation conditions in soil burial tests.

The Interaction of Microplastics and Microbioplastics with Soil and a Comparison of Their Potential to Spread Pathogens

Microplastics contribute to various environmental issues and serve as carriers for a wide range of toxic compounds such as pesticides, pharmaceuticals, and metal ions. Consequently, there is a gradual shift towards replacing them with biodegradable plastics (bioplastics). However, biodegradable plastics require specific conditions for complete biodegradation, and their biodeterioration often leads to the rapid production of smaller fragments, known as microbioplastics. In this review, we summarize selected issues related to the impact of plastic particles on soil properties and the soil microbiome. Findings from numerous studies indicate that both microplastics and microbioplastics induce adverse changes in soil microbiology, potentially increasing the abundance of soil-borne pathogens. Based on these observations, we argue that plastic particles could serve as carriers for colonies of soil-borne pathogens. Furthermore, the use of bioplastics may exacerbate this issue due to their easier and faster formation, increased support for biofilms, and more pronounced adverse effects on soil biota. However, further research is necessary to either substantiate or refute this perspective.

The Potential of AOP Pretreatment in the Biodegradation of PS and PVC Microplastics by Candida parapsilosis

Microplastics are an emerging class of recalcitrant organic pollutants that are of general scientific and public interest nowadays. It would be ideal to remove microplastics from the environment through biodegradation, as biodegradation is a highly ecological and economically acceptable approach. Unfortunately, the efficiency of biodegradation of conventional plastic polymers is low. The application of a suitable pretreatment could increase the efficiency of biodegradation. In this study, the applicability of UV-C/H2O2 and UV-C/S2O82− advanced oxidation processes as pretreatments for the biodegradation of polystyrene and poly(vinyl chloride) microplastics by the yeast Candida parapsilosis was investigated. For the investigated range (pH 4–10, peroxide concentration up to 20 mM and treatment duration up to 90 min), the UV-C/H2O2 process proved to be more effective in degrading polystyrene microplastics, while the UV-C/S2O82− process was more efficient at degrading poly(vinyl chloride) microplastics. Samples pretreated under optimal conditions (90 min treatment time at a pH of 5.7 and H2O2 concentration of 20.0 mM for polystyrene samples; 90 min treatment time at a pH of 8.6 and S2O82− concentration of 11.1 mM for poly(vinyl chloride) samples) were subjected to biodegradation by Candida parapsilosis. The biodegradation conditions included an agitation speed of 156 rpm and an initial pH of 5.7 for the experiments with the polystyrene samples, while an agitation speed of 136 rpm and an initial pH of 4.9 were used for the poly(vinyl chloride) experiments. The initial value of the optical density of the yeast suspension was 1.0 in both cases. The experiments showed a positive effect of the pretreatment on the number of yeast cells on the surface of the microplastics.

Degradation and inhibition kinetics of phenanthrene by Alcaligenes ammonioxydans, [VITRPS2] strain isolated from petroleum-contaminated soil

Phenanthrene, a common three-ring polyaromatic hydrocarbon [PAH], originates from sources like grilled meals, tobacco, crude oil, coal tar, and automobile exhaust. Recognized as a hazardous PAH, it is often targeted for bioremediation due to its sustainability and potential for full mineralization. In this study, we focus on biodegrading phenanthrene using the strain Alcaligenes ammonioxydans [VITRPS2], isolated from petroleum-contaminated soil. At 5 mg/ml, degradation occurred at a rate constant of 0.0181/day, with half-life values of 2.7 and 4.49 according to first and second-order kinetics, respectively. Employing a one-factor-at-a-time [OFAT] approach, we optimized biodegradation conditions within Luria–Bertani [LB] media. Under optimal conditions—pH 8.0, 8% inoculum concentration, and 37 °C incubation over seven days—the strain achieved maximal growth with phenanthrene as the sole carbon source. It exhibited a degradation efficiency of up to 72% for phenanthrene under these conditions. Gas chromatography-mass spectrometry [GC–MS] analysis revealed principal metabolites of the breakdown pathway, including salicylic acid, catechol, and various phthalic acid derivatives. This underscores the strain's potential for remediating environments polluted by PAH metabolites, showcasing its remarkable capability for complete phenanthrene degradation.Graphical abstract

Strategic enzymatic biodegradation of pharmaceutical pollutant carbamazepine by bacteria Rhodococcus zopfii

Carbamazepine is frequently detected in wastewater, impacts human health and the environment. This study evaluates the biodegradation of carbamazepine by Gram-positive bacteria Rhodococcus zopfii, specifically optimum biodegradation conditions and extracellular enzyme roles. The carbamazepine biodegradation optimization and bacteria growth for initial concentrations of carbamazepine, pH and temperatures were investigated. Extracellular enzyme assays were also examined. For the carbamazepine biodegradation, the optimum initial concentration, pH and temperature were at 10 mgL-1, pH 7 and 40 ℃, respectively with the carbamazepine biodegradation percentages ranging from 99.92 ± 0.04 % to 99.98 ± 0.14 %. The optimum parameter conditions for the bacteria growth were 5 mgL-1, pH 7 and 40 ℃ with a range from 9.61 ± 0.01 log CFUmL-1 to 10.35 ± 0.00 log CFUmL-1. The bacteria growth and the carbamazepine biodegradation occurred sequentially, with the bacteria growth preceding the carbamazepine biodegradation. The highest extracellular enzyme secreted by R. zopfii was aldehyde oxidase, followed by oxygen oxidoreductase, catechol 1,2 dioxygenase and catechol 2,3 dioxygenase. At the early of the biodegradation, oxygen oxidoreductase and aldehyde oxidase were secreted, then followed by catechol 1,2 dioxygenase and catechol 2,3 dioxygenase. A linear correlation between oxygen oxidoreductase with the biodegradation of carbamazepine was identified. Such phenomenon revealed R. zopfii metabolised carbon from the phenolic compound, thus reducing carbamazepine toxicity for defence and biodegradation mechanisms compared to growth. This study provides vital information for the biodegradation of carbamazepine using Gram-positive bacteria R. zopfii as a sustainable technology, mimics nature that is beneficial for wastewater treatment management and industry application.

Removal mechanisms of illicit and psychoactive drugs in different wastewater treatment processes

For illicit and psychoactive drugs which remain in the water phase, better removal was linked to improved biodegradation conditions.

Isolation and Characterization of a Diesel-degrading Bacterium From Waters Near the Langkawi UNESCO Kilim Karst Geoforest Park

This study explored the biodegradation potential of bacterial isolates from various locations in Malaysia, focusing on their ability to utilize diesel as a carbon source. Among the ten isolates tested, isolate 4, identified as Pseudomonas sp. strain UPM-Langkawi 3 based on morphological, cultural, and biochemical properties, exhibited significant growth on 2.5% diesel, indicating rapid activation of diesel assimilation mechanisms. Using the ABIS online software analysis, the strain was provisionally identified as Pseudomonas sp. UPM-Langkawi 3. Experimental results demonstrated that the optimal conditions for the growth of strain UPM-Langkawi 3 were between 6 and 8 % (v/v) diesel concentration, a temperature of between 28 and 35 °C, and a pH range of between 7.5 to 8.5. The strain showed inhibited growth at higher diesel concentrations and temperatures above 40 °C, as well as at a lower pH of 5.7. Among several inorganic nitrogen sources tested, 0.9% w/v ammonium sulphate was found to be the most effective, corroborating previous research. The study underscores the efficacy of Pseudomonas sp. strain UPM-Langkawi 3 in degrading diesel, suggesting its potential use in bioremediation of diesel-contaminated environments. Further research should employ molecular identification techniques, such as 16srRNA gene sequencing, to confirm the species identity and optimize biodegradation conditions. This work establishes a foundation for utilizing indigenous bacterial strains in environmental management strategies, particularly for areas impacted by hydrocarbon pollutants.

Optimisation of PAHs biodegradation by Klebsiella pneumonia and Pseudomonas aeruginosa through response surface methodology

ABSTRACT Response Surface Methodology (RSM) with Box–Behnken Design (BBD) is used to optimise the Phenanthrene (PHE) degradation process by Klebsiella pneumoniae (K bacteria) and Pseudomonas aeruginosa (P bacteria). Wherein substrate concentration, temperature, and pH at three levels are used as independent variables, and degradation rate of PHE as dependent variables (response). The statistical analysis, via ANOVA, shows coefficient of determination R2 as 0.9848 with significant P value 0.0001 fitting in second-order quadratic regression model for PAHs removal by Klebsiella pneumonia, and R 2 as 0.9847 with significant P value 0.0001 by P bacteria. According to the model analysis, temperature (P < 0.0006) is the most influential factor for PHE degradation efficiency by K bacteria, while pH (P < 0.0001) is the most influential factor for PHE degradation by P bacteria. The predicted optimum parameters for K bacteria, namely, temperature, substrate concentration, and pH are found to be 34.00℃, 50.80 mg/L, and 7.50, respectively, and those for P bacteria are 33.30℃, 52.70 mg/L, and 7.20, respectively. At these optimum conditions, the observed PHE removal rates by two bacteria are found to be 83.36% ± 2.1% and 81.23% ± 1.6% in validation experiments, respectively. Thus RSM can optimise the biodegradation conditions of both bacteria for PHE.

Biodegradation of naphthalene – Ecofriendly approach for soil pollution mitigation

Naphthalene (NPT), a widely used household pest repellent and insecticide obtained from crude oil, serves as a toxic pollutant to non-target living matter. The stable and resistant nature of NPT makes it difficult to degrade through the physiochemical processes. The present study investigated the bacterial degradation of NPT isolated from crude oil-contaminated soil. Initially, the potent bacteria, Bacillus sp. GN 3.4, were isolated by enrichment culture method and subsequently assessed for NPT biodegradation. The optimum conditions for NPT biodegradation were pH 7.0 at 37 °C, 80 mg/L (initial NPT), 3% v/v (inoculum dose), and 7 days of treatment which showed 100% biodegradation. Furthermore, GC–MS analysis revealed the presence of degradation metabolites, namely, salicylate and hydroquinone indicating potential metabolic pathways. Considering the water-solubility and non-toxic nature of these metabolites, the results imply that Bacillus sp. GN 3.4. could potentially play a role in bioremediation by aiding in eliminating NPT from the soil.

Assessment of the Plasmid Mediated Biodegradation of Crude Oil under Optimal Growth Conditions

The present study was undertaken to assess the role of plasmid-mediated biodegradation of crude oil under optimal growth conditions. Enrichment techniques, turbidometric test, antimicrobial susceptibility testing, plasmid curing test and optimal biodegradation conditions were carried out using standard procedures. The results indicated that 22 of the isolates were observed to have high pollutant degrading potentials (A600nm &gt; 0.3) due to their crude oil utilization ability. Isolates designated as C1, D1, L2 and J3 showed various degrees of growth after curing of their plasmids whereas isolates G2, H4, K4 and I6 were unable to grow after plasmid removal. It was observed that 4 plasmid-borne cells resisted the antibiotics tested after pre-cured examination but these isolates were 95% sensitive to the same antibiotics after post cured test. The results further indicated that isolates which were able to degrade crude oil belonged to genera Bacillus, Pseudomonas sp., Ochrobacterium sp. and Enterobacter sp. Moreso, neutral pH, 35 °C temperature and 3 % crude oil concentration were found to be optimal conditions for crude oil bioaugmentation study. Thus, the study indicated that the crude oil-utilizing bacteria which are part of the soil ecosystem could be exploited for natural and terrestrial remediation of crude oil-polluted environments.

Characterization and biodegradation of paracetamol by Bacillus pumilus strain PYP2

As we know the recent pandemic, coronavirus disease (COVID-19) due to SARS CoV-2 virus has led to an increase in the consumption of various drugs as medicines by the patients. Paracetamol (acetaminophen, APAP) act as an emerging contaminant classified among the class pharmaceutical and personal care pollutant (PPCP) and is detected in wastewater and sewage systems. The enrichment culture approach was used for the isolation APAP-degrading bacterium wastewater sample. Microscopic examination, biochemical and 16S rRNA sequence analysis showed that the isolate PYP-2 belongs to the Bacillus pumilus strain. Shake flask and batch culture degradation studies have shown that the strain can degrade APAP. Further, the response surface methodology (RSM) plot was used to know the best physical condition for biodegradation by optimization study. The optimum pH of 5.0, temperature of 30 °C, agitation speed of 146 rpm, and APAP 267 mg/L concentration were reported for PYP-2-based degradation. Bacterial biomass kinetic analysis was performed at the best physical condition, and the results showed that the specific growth rate (µ) was 713 mg/L. Oxalic acid, 2-isopropyl-5-methyl cyclohexanone, and phenothiazine were the intermediates of the APAP degradation pathway detected by the GC-MS chromatogram peaks. Therefore, this research has shown that Bacillus pumilus strain PYP-2 has the metabolic capacity to biodegrade APAP, providing new tools for bioremediation.

Aerobic aquatic biodegradation of bio-based and biodegradable polymers: Kinetic modeling and key factors for biodegradability

With the increasing concern about plastic waste, numerous efforts have been made to find substitutes for existing non-biodegradable synthetic polymers. Bio-based and/or purported petroleum-based biodegradable polymers are considered probable plastic replacement candidates. However, the durability of non-biodegradable plastic is a key feature of plastics. Thus, a balance must be achieved between biodegradation and environmental material stability. The objective of this study is to determine the impact of crystallinity, molecular chemistry, and hydrophilicity on the rate of aquatic biodegradation of biobased plastic materials. In the present study, twelve bio-based/purported biodegradable materials were investigated under aerobic aquatic biodegradation conditions for 56 days by tracking oxygen consumption. Crystallinity, hydrophobicity, chemistry, and chemical structure were varied to understand potential means for controlling the rate of biodegradation. The biodegradation kinetics were analyzed and discussed, relating to the characteristics of polymers. Polyvinyl alcohol (PVA), Chitosan, Rayon, Polyhydroxy-butyrate-co-valerate (PHBV), PHBH, and Polybutylene succinate (PBS) showed the biodegradation extents over 70% at 56 days. Cellulose acetates (CAs) and Polylactic acid (PLA) showed biodegradation extent lower than 20%. The chemistry of the polymer backbone chain, substituent structure, and degree of substitution were the dominant factors affecting biodegradation. The crystallinity of the polyesters had a negative correlation with the initial biodegradation rate and the ultimate biodegradation of polyesters, and the hydrophobicity of the polymers delayed the initiation of biodegradation. The aerobic aquatic biodegradation results related to the polymer characteristics are useful for product designers and environmental scientists to understand the fate of these polymeric materials in the environment.

Investigation of the influence of plasticizers on the biodegradability of cellulose acetate

AbstractIn order to evaluate the biodegradability of the cellulose acetate (CA) films plasticized with different concentrations of glycerol (GLY) or triethyl citrate (TEC), analysis of scanning electron microscopy (SEM), Fourier transfer infrared spectroscopy (FTIR), and thermogravimetric analyses (TGA) were conducted through 180 days. Throughout the analysis, indicators of plasticizer exudation were observed, including changes in visual appearance and mass loss, ranging from 39.141% and 20.663% (first day) up to 0.524% and 0.488% (last day) for TEC and GLY plasticizer based films, respectively. Changes were also noted in the infrared spectrum, and TGA plots with polymer degradation peaks from 332.09 to 400.96 cm−1 for both plasticizers based films (TEC and GLY, respectively), regardless of the day of analysis. All assays revealed plasticizer losses, but there was no evidence of films' biodegradation during the experimental time. In perspective, this systematic approach can be extended to study other polymers and other biodegradation conditions.

Biodegradation of 17 β-estradiol by Serratia marcescens and Stenotrophomonas tumulicola co-culture isolated from a sewage treatment plant in Upper Egypt.

17 β-estradiol (E2) is an important pollutant of the aquatic system. It is responsible for sexual disruptions in the majority of aquatic organisms. This study aimed to search for bacteria with high potential degradation of E2 as an important method for bioremediation. Sewage water samples were collected and treated to isolate bacterial strains which were identified by conventional methods and 16S ribosomal RNA gene sequence analysis. The biodegradation of E2 by the isolated strains was evaluated under different environmental conditions. Two bacterial strains were recovered from sewage water samples and identified as Stenotrophomonas tumulicola and Serratia marcescens, (named ASc2 and ASc5 respectively). Co-culture of the two strains showed biodegradation of approximately 93.6 % of E2 (50 mg. L-1) within 48 hours. However, the biodegradation capacity of the same E2 concentration was 69.4% and 71.2% for ASc2 and ASc5 each alone, respectively. The optimum cultivation conditions for efficient E2 biodegradation by co-culture were 5% (v/v) inoculation volume with 50 mg. L-1 of E2 as the initial concentration at pH 7 and 30°C within 48 hours inoculation period. This study detected new bacterial strains that are capable of rapid degradation of estrogen as an environmental pollutant.

Biodegradation of low density polyethylene (LDPE) by Paenibacillus Sp. and Serratia Sp. isolated from marine soil sample

Low Density Polyethylene (LDPE) is recalcitrant and poses serious threats to our environment. The present study explored the LDPE biodegradation potential of aerobic bacteria enriched from offshore of RK beach Visakhapatnam. These isolates were specifically enriched in MSAM medium which contains LDPE as the source of carbon and energy for the growth. Six strains were isolated; among these S-6 & S-2 are the most potent strains which were attributed to the degrading ability. The phenotypic fingerprint such as Gen III biolog was used to identify the LDPE degrading S-6 as Paenibacillus sp. and S-2 as Serratia sp. respectively. Gen III Microlog, a phenotypic microarray; have been used for analysis of relative capabilities for substrate utilization of S-6 and S- 2 strains. The contact time of 72 h, temperature of 37 °C, pH of 7.1, inoculum volume 4% v/v, and weight of LDPE films 0.030 g were found to be optimal conditions for biodegradation of LDPE. Efficiency of these microbes (Paenibacillus sp. and Serratia sp) in degradation of LDPE was studied by percent weight reduction during a time period of 35 days. The Paenibacillus sps. proved to be most efficient with a weight loss of 22.46% compared to Serratia sps. with a weight loss of 9.5%. These bacterial species are capable of utilising LDPE as the sole carbon and energy source.

Biodegradation of dibutyl phthalate and diethyl phthalate by indigenous isolate Bacillus sp. MY156: Characterization, stoichiometry, enzyme activity, and physiological response to cell surface

An indigenous bacterial strain, Bacillus sp. MY156, was isolated from a local wastewater treatment plant and utilized for degradation of dibutyl phthalate (DBP) and diethyl phthalate (DEP). The isolate showed a substrate preference of DBP to DEP. The optimal biodegradation conditions were pH 7, 30 °C, 0.2 (in terms of OD600) inoculum size, and 2 % (v v−1) bacterial load. The biodegradation of DBP and DEP as sole carbon source was comprehensively investigated via degradation kinetics and mass balance analysis. The isolate achieved complete degradation and over 80 % removal of 300 mg L−1 DBP within 60 h and 200 mg L−1 DEP in 5 days. The biodegradation of DBP and DEP fitted the inhibitory kinetic model, and the maximum degradation rates for DBP and DEP were 183.34 and 66.90 mg L−1 day−1, respectively. The cell surface responses to biodegradation were investigated by analyses of morphology, Fourier transform-infrared, and extracellular polymeric substance. The potential intermediates were mono-n-butyl phthalate, mono-ethyl phthalate, phthalic acid, and protocatechuic acid by β-oxidation, hydrolysis, and decarboxylation. The esterase and dehydrogenase activities reached the highest at the initial and middle phases during biodegradation. The docking studies also elucidated the relevant enzyme preferred DBP to DEP via binding energy and bond distance.

Two strains of bacteria from oilfield slickwater and their performance in partially hydrolyzed polyacrylamide biodegradation

Partially hydrolyzed polyacrylamide (HPAM) is widely used in oil recovery, but the HPAM residues also induce environmental pollution. In this study, two strains of bacteria, SCE2 and NMYGYB4, have been isolated from oilfield slickwater and identified as Tistrella bauzanensis (SCE2) and Brucella sp. (NMYGYB4). The optimal biodegradation conditions of Tistrella bauzanensis SCE2 were inoculation time 36 h, shaking speed 175 rpm, inoculum amount 3% (v/v), pH 3.0, and incubation temperature 37 °C with urea and glucose as the nitrogen and carbon sources. And the optimal biodegradation conditions of Brucella sp. NMYGYB4 were 12 h, 185 rpm, 2% (v/v), pH 7.0 and 37 °C with yeast powder and sucrose as the nitrogen carbon sources. HPAM removal rate of Tistrella bauzanensis SCE2 and Brucella sp. NMYGYB4 reached 75.3% and 63.59% at optimal conditions. The degraded samples were analyzed with GPC, FTIR, 1H NMR and HPLC. The results showed that HPAM was broken into small fragments, and amide group has been converted into carboxyl group, and no toxic acrylamide monomer was produced. The specific activities of extracellular amidases of Tistrella bauzanensis SCE2 and Brucella sp. NMYGYB4 were 5.31 U/mg and 4.79 U/mg, respectively. This work will provide novel bacteria strains for HPAM-containing wastewater treatment.

Biodegradation and process optimization of phenol and formaldehyde by Aspergillus nomius SGFA1

Phenols and formaldehyde are often simultaneously discharged into the environment with sewage, and due to their highly toxic to organisms, few have been reported to be degraded simultaneously. This study investigated the simultaneous biodegradation of phenol and formaldehyde using the highly efficient formaldehyde-degrading fungus Aspergillus nomius SGFA1, which was previously isolated and identified in our laboratory. The response surface methodology was used to optimize the biodegradation conditions of phenol and formaldehyde; the optimum temperature, initial pH, and glucose content were determined to be 28.1 °C, 5.0, and 0.89%, respectively, under which the maximum degradation rates of phenol and formaldehyde reached 89.7% and 85.3%, respectively. Mass balance and stoichiometric analysis revealed 0.26 g⋅g−1 and 0.05 g⋅g−1 conversions of phenol and formaldehyde carbon to biomass, respectively. The degradation pathway demonstrated that phenol hydroxylase (PHE) and formaldehyde dehydrogenase (FALDH) were the key enzymes for phenol and formaldehyde degradation, with enzyme activities reaching maxima of 0.008 and 1.09 U⋅mg−1 at 8 and 6 h, respectively. This study demonstrated the ability of A. nomius SGFA1 to effectively remove phenol and formaldehyde simultaneously, providing new information on the use of microorganisms to reduce environmental pollution.

Growth Optimization of Naphthalene-Degrading Pseudomonas Stutzeri Strain BUK_BTEG1 Isolated from Petrochemical Contaminated Soil.

Bioremediation of PAHs such as naphthalene by the activity of microorganisms represents an eco-friendly, economical, and safe decontamination approach compared physical and chemical processes. In this study, the biodegradation conditions for naphthalene by Pseudomonas stutzeri strain BUK_BTEG1 was optimized through onfactor-at-a-time (OFAT). The Characterization was conducted by studying the effect of incubation time, nitrogen source, pH, inoculum size, substrate concentration and temperature in BH media containing naphthalene as sole source of carbon and energy. The growth and degradation of naphthalene by this strain was optimal at 1000 mg/L ammonium Nitrate, substrate concentration of 800mg/L, temperature of 35 °C, pH of 7.0, inoculum size of 4% (v/v) and 72 hours of incubation time. After 72 hours of incubation under optimal conditions, the degradation efficiency of this strain to naphthalene was 72%. The analysis using gas chromatography-mass spectrometry reveals 1,2-naphthalenediol, 1-hydroxy-napthoic acid, 1,4-Napthoquinone, salicylic acid, and catechol as metabolites of naphthalene degradation by comparing the fragmentation pattern and mass spectrum obtained with data available on NIST library. This strain demonstrates promising potential and could be handy for its application in the bioremediation of naphthalene contaminated sites.