Isolation and characterization of bacteria from soil contaminated with diesel oil and the possible use of these in autochthonous bioaugmentation

Two bacterial species (isolates N and O) were isolated from a paddy soil microcosm that had been artificially contaminated with diesel oil to which extrinsic Pseudomonas aeruginosa strain WatG, had been added exogenously. One bacterial species (isolate J) was isolated from a similar soil microcosm that had been biostimulated with Luria–Bertani (LB) medium. Isolates N and O, which were tentatively identified as Stenotrophomonas sp. and Ochromonas sp., respectively, by sequencing of their 16 S rRNA genes had no ability to degrade diesel oil on their own in any liquid medium. When each strain was cocultivated with P. aeruginosa strain WatG in liquid mineral salts medium (MSM) containing 1% diesel oil, isolate N enhanced the degradation of diesel oil by P. aeruginosa strain WatG, but isolate O inhibited it. In contrast, isolate J, which was tentatively identified as a Rhodococcus sp., degraded diesel oil contained not only in liquid LB and MSM, but also in paddy soil microcosms supplemented with LB medium. The bioaugmentation capacity of isolate J in soil microcosms contaminated with diesel oil was much higher than that of P. aeruginosa strain WatG. The possibility of using isolate J for autochthonous bioaugmentation is discussed.     

Enhanced biodegradation of diesel oil by a newly identified Rhodococcus baikonurensis EN3 in the presence of mycolic acid

AIMS: The aim of the present study was to isolate and characterize a bacterium, strain EN3, capable of using diesel oil as a major carbon and energy source, and to analyse the enhancement of diesel oil degradation by this organism using synthetic mycolic acid (2-hexyl-3-hydroxyldecanoic acid). METHOD AND RESULTS: An actinomycete with the ability to degrade diesel oil was isolated from oil contaminated soil and characterized. The strain had phenotypic properties consistent with its classification in the genus Rhodococcus showing a 16S rRNA gene similarity of 99.7% with Rhodococcus baikonurensis DSM 44587(T). The ability of the characterized strain to degrade diesel oil at various concentrations (1000, 5000, 10 000 and 20 000 mg l(-1)) was determined. The effect of synthetic mycolic acid on the biodegradation of diesel oil was investigated at the 20 000 mg l(-1) concentration; the surfactant was added to the flask cultures at three different concentrations (10, 50 and 100 mg l(-1)) and degradation followed over 7 days. Enhanced degradation was found at all three concentrations of the surfactant. In addition, the enhancement of diesel oil degradation by other surfactants was observed. CONCLUSIONS: The synthetic mycolic acid has potential for the remediation of petroleum-contaminated sites from both an economic and applied perspective as it can stimulate biodegradation at low concentrations. SIGNIFICANCE AND IMPACT OF THE STUDY: This study showed that the synthesized mycolic acid can be used for potential applications in the bioremediation industries, for example, in oil spill clean-up, diesel fuel remediation and biostimulation.     

Isolation and Characterization of Novel Strains of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> and <Emphasis Type="Italic">Serratia marcescens</Emphasis> Possessing High Efficiency to Degrade Gasoline,Kerosene, Diesel Oil,and Lubricating Oil

Bacteria possessing high capacity to degrade gasoline, kerosene, diesel oil, and lubricating oil were screened from several areas of Hokkaido, Japan. Among isolates, two strains, WatG and HokM, which were identified as new strains of Pseudomonas aeruginosa and Serratia marcescens species, respectively, showed relatively high capacity and wide spectrum to degrade the hydrocarbons in gasoline, kerosene, diesel, and lubricating oil. About 90-95% of excess amount of total diesel oil and kerosene added to mineral salts media as a sole carbon source could be degraded by WatG within 2 and 3 weeks, respectively. The same amount of lubricating oil was 60% degraded within 2 weeks. Strain HokM was more capable than WatG in degrading aromatic compounds in gasoline. This strain could also degrade kerosene, diesel, and lubricating oil with a capacity of 50-60%. Thus, these two isolates have potential to be useful for bioremediation of sites highly contaminated with petroleum hydrocarbons.     

Novel lipopeptide biosurfactant produced by hydrocarbon degrading and heavy metal tolerant bacterium Escherichia fergusonii KLU01 as a potential tool for bioremediation

Escherichia fergusonii KLU01, a propitious bacterial strain isolated from oil contaminated soil was identified to be hydrocarbon degrading, heavy metal tolerant and a potent producer of biosurfactant using diesel oil as the sole carbon and energy source. The biosurfactant produced by the strain was characterized to be a lipopeptide. The minimum active dose and critical micelle concentration of the biosurfactant were found as 0.165±0.08 μg and 36 mg/L, respectively. In spite of being an excellent emulsifier, the biosurfactant showed an incredible stability at extremes of temperature, pH and at various concentrations of NaCl, CaCl? and MgCl?. Also the bacterium manifested tolerance towards Manganese, Iron, Lead, Nickel, Copper and Zinc. The strain emerges as a new class of biosurfactant producer with potential environmental and industrial applications, especially in hydrocarbon degradation and heavy metal bioremediation.     

Molecular characterization of a lipase-producing <Emphasis Type="Italic">Bacillus pumilus</Emphasis> strain (NMSN-1d) utilizing colloidal water-dispersible polyurethane

Bacillus pumilus strain NMSN-1d isolated from polyurethane-contaminated water was found to grow in high salt concentration (NaCl 10%, w/v) and degrade Impranil-DLN, water-dispersible polyurethane. The genetic relatedness of the isolate has been established by standard molecular biological techniques and the enzyme(s) involved in polyurethane degradation were also studied. A total of nine bacterial strains were isolated from polyurethane-polluted sites and characterized by conventional, microbiological and biochemical methods. These isolates were subjected to 16S ribosomal RNA gene amplification by PCR using specific primers. The genetic relatedness of the isolates was also ascertained by ribotyping and BLAST analysis of the 16S ribosomal RNA gene sequences. The bacterial isolates were grown in yeast extract-salts minimal broth medium supplemented with water-dispersible polyurethane (Impranil DLN) as a sole source of carbon. The promising isolate utilizing polyurethane and producing lipase was identified as Bacillus pumilus NMSN-1d. The polyurethane degradation has been studied in polyurethane-Rhodamine-B and Luria-Bertani-polyurethane plate assays. The activity of hydrolytic enzymes such as lipase and esterase was confirmed on 2xYT-olive oil and tributyrin-Tween 20 plate assay. The newly isolated Bacillus pumilus appears promising in the management of polyurethane waste and in production of industrially important enzymes.     

Isolation and Characterization of a New Benzene,Toluene, and Ethylbenzene Degrading Bacterium, <Emphasis Type="Italic">Acinetobacter</Emphasis> sp. B113

A bacterium designated strain B113, able to degrade benzene, toluene, and ethylbenzene compounds (BTE), was isolated from gasoline-contaminated sediment at a gas station in Geoje, Korea. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belonged to the genus Acinetobacter. The biodegradation rates of benzene, toluene, and ethylbenzene were relatively low in MSB broth, but the addition of yeast extract had a substantial impact on the biodegradation of BTE compounds, which suggested that yeast extract might provide a factor that was necessary for its growth or BTE biodegradation activity. However, interestingly, the biodegradation of BTE compounds occurred very quickly in slurry systems amended with sterile soil. Moreover, if soil was combusted first to remove organic matters, the enhancement effect on BTE biodegradation was lost, indicating that some insoluble organic compounds were probably beneficial for BTE degradation in contaminated sediment. This study suggests that strain B113 may play an important role for biodegradation of BTE in the contaminated site.     

Bioremediation potential of hydrocarbon degrading bacteria: isolation,characterization, and assessment

Oil contamination is a worldwide concern now. However, oil contaminated environment is enriched with microorganisms that can utilize petroleum oil and use hydrocarbon for their growth, nutrition and metabolic activities. In the present study, bacteria present in the oil contaminated soil were isolated by enrichment culture technique using Minimal Salt (MS) media supplemented with diesel oil and burned engine oil as a sole carbon source. The isolated bacteria were characterized by morphological and biochemical tests and identified by molecular tool through cycle sequencing method. Three isolates were morphologically characterized as gram-negative, cocci shaped and 16S rRNA sequence analysis revealed that the isolates are closely related to Pseudomonas sp., Acinetobacter sp., and Enterobacter sp. respectively. Growth condition was optimized at pH 7.0 and temperature 37 °C. All the isolates were susceptible to several antibiotics and they have no antagonistic effect with soil beneficial bacteria. Three isolates were grown in two different concentrations of diesel oil and burned engine oil (4% v/v and 8%, v/v) respectively. Study revealed that with increasing the concentration of diesel oil in the media the growth rate of all the isolates were decreased. In contrast, the growth rates of all the three isolates were increased, with increasing concentration of burned engine oil. In our study, all the isolates showed their degradation efficacy in 4% v/v diesel oil and in 8% v/v burned engine oil. So, our research clearly shows that the isolates could be potentially used for bioremediation purposes for cleaning up petroleum polluted area.     

Diversity of biosurfactant producing microorganisms isolated from soils contaminated with diesel oil

Biosurfactant production is a desirable property of hydrocarbon-degrading microorganisms (HDM). We characterized biosurfactant producing microbial populations from a Long Beach soil, California (USA) and a Hong Kong soil (China), contaminated with diesel oil. A total of 33 hydrocarbon-utilizing microorganisms were isolated from the soils. Twelve isolates and three defined consortia were tested for biosurfactant production and emulsification activity. The highest reduction of surface tension was achieved with a consortium of L1, L2 and L3 isolates from a Long Beach soil (41.4mN m(-1)). Isolate L1 (Acinetobacter junii) displayed the highest reduction of surface tension (46.5 mN m(-1)). The emulsifying capacity evaluated by the E24 emulsification index was highest in the culture of isolate L5 (74%). No substantial emulsification was achieved with the cell-free extracts, indicating that the emulsifying activity was not extracellular. Based on surface tension and the E24 index results, isolates F1, F2, F3, F4, L1, L2, L3 and L4 were identified by 16S rRNA gene sequencing as Bacillus cereus, Bacillus sphaericus, B. fusiformis, Acinetobacter junii, a non-cultured bacterium, Pseudomonas sp. and B. pumilus, respectively. Cluster analyses of 16S rRNA gene sequences of the bacterial isolates revealed 70% similarity amongst hydrocarbon-degrading bacterial community present in both soils. Five isolates (isolates F1, F2, F3, F4 and L4) belong to the Firmicutes order, two isolates (L1 and L3) belong to the Proteobacteria order and one isolate (L2) is an Actinomyces sp. Simpson's index (1 - D) and the Shannon-Weaver index (H) revealed more diversity of HDM in the Hong Kong soil, while evenness (E) and the equitability (J) data indicated that there was not a dominant population. Bacterial isolates displaying substantial potential for production of biosurfactants can be applied in the bioremediation of soils contaminated with petroleum hydrocarbons.     

Biodegradation of petroleum hydrocarbons by filamentous fungi (Aspergillus ustus and Purpureocillium lilacinum) isolated from used engine oil contaminated soil

The use of microorganisms for remediation and restoration of hydrocarbons contaminated soils is an effective and economic solution. The current study aims to find out efficient telluric filamentous fungi to degrade petroleum hydrocarbons pollutants. Six fungal strains were isolated from used engine (UE) oil contaminated soil. Fungi were screened for their ability to degrade crude oil, diesel and UE oil using 2.6-dichlorophenol indophenol (DCPIP). Two isolates were selected, identified and registered at NCBI as Aspergillus ustus HM3.aaa and Purpureocillium lilacinum HM4.aaa. Fungi were tested for their tolerance to different concentration of petroleum oils using radial growth diameter assay. Hydrocarbons removal percentage was evaluated gravimetrically. The degradation kinetic of crude oil was studied at a time interval of 10 days. A.ustus was the most tolerant fungi to high concentration of petroleum oils in solid medium. Quantitative analysis showed that crude oil was the most degraded oil by both isolate; P. lilacinium and A. ustus removed 44.55% and 30.43% of crude oil, respectively. The two fungi were able to degrade, respectively, 27.66 and 21.27% of diesel and 14.39 and 16.00% of UE oil. As compared to the controls, these fungi accumulated high biomass in liquid medium with all petroleum oils. Likewise, crude oil removal rate constant (K) and half-lives (t_1/2) were 0.02 day⁻¹, 34.66 day and 0.015 day⁻¹, 46.21 day for P. lilacinium and A. ustus, respectively. The selected fungi appear interesting for petroleum oils biodegradation and their application for soil bioremediation require scale-up studies.     

一株联苯降解菌的特性及鉴定*

从华北油田污染土壤中筛选出一株能够以联苯为唯一碳源和能源生长的菌株。该菌生长的最适联苯浓度为0．2％～0．4％,在联苯浓度为0．1％的培养基中培养36h后降解率达99．8%。该菌还可以降解苯甲酸钠、邻苯二酚、间苯二酚、对苯二酚和多氯联苯Aroclorl221、Aroclorl242等芳香族化合物。通过16S rDNA基因序列分析鉴定该菌为嗜吡啶红球菌(Rhodococcus pyridinovorans)。     

Bioremediation of 6 % [w/w] Diesel‐Contaminated Mainland Soil in Singapore: Comparison of Different Biostimulation and Bioaugmentation Treatments

The efficacy of indigenous microorganisms to degrade diesel oil in contaminated mainland sites in Singapore was investigated. A semi‐scale trial was made by spiking topsoil with 6 % [w/w] of diesel oil. The results indicated that in the presence of NPK commercial (Rosasol®) fertilizer a 53 % reduction in contaminant concentration was recorded after 60 days compared to untreated controls while the addition of a mixture of urea and K₂HPO₄ effected a 48 % reduction in the Total Recoverable Petroleum Hydrocarbons. A commercial culture and an enriched/isolated microbial association proved to be the least effective with 25 and 9 % reductions, respectively. The results confirmed the bioremediation potential of indigenous microorganisms for diesel‐oil contaminated mainland soil. Identification of the persistent compounds was done and perceived as a tool in decision‐making on strategies for speeding up of the degradation process to achieve clean‐up standards in shorter remediation periods.     

Characterization of novel diesel-degrading strains <Emphasis Type="Italic">Acinetobacter haemolyticus</Emphasis> MJ01 and <Emphasis Type="Italic">Acinetobacter johnsonii</Emphasis> MJ4 isolated from oil-contaminated soil

The diesel-degrading strains, designated as MJ01 and MJ4, were isolated from oil-contaminated soil in Daejeon (South Korea) and were taxonomically characterized using a polyphasic approach and their diesel oil degradation abilities were analyzed. The isolates MJ01 and MJ4 were identified as Acinetobacter haemolyticus and Acinetobacter johnsonii, respectively, based on their 16S rDNA gene sequences, DNA–DNA relatedness, fatty acid profiles and various physiological characteristics. Strains MJ01 and MJ4 were able to use diesel oil as the sole carbon and energy source. Both strains could degrade over 90% of diesel oil with an initial concentration of 20,000 mg/l after incubation for 7 days, the most significant degradation occurred during the first 3 days. To our knowledge, this is the first report on diesel oil-degrading microorganisms among bacterial strains belonging to A. haemolyticus and A. johnsonii.     

Degradation of Trichloroethylene by <Emphasis Type="Italic">Bacillus</Emphasis> sp.: Isolation Strategy,Strain Characteristics,and Cell Immobilization

A novel isolate of a bacterium, capable of degrading trichloroethylene (TCE) and growing on this as the sole carbon source is reported. The test strain was isolated by an enrichment technique with trichloroethylene as the substrate. The isolated strain belongs to the genus Bacillus. The practical utility of cleaning up oil spillage by bioremediation could be extended to this bacterium to degrade the environmental pollutant, which is used in metal degreasing in industries. Cells of the novel bacterium immobilized on calcium alginate were found to have better trichloroethylene degrading activity than the ones which were immobilized on agar-agar or free cells.     

A novel pathway for the biodegradation of gamma-hexachlorocyclohexane by a Xanthomonas sp. strain ICH12

AIM: To isolate gamma-hexachlorocyclohexane (HCH)-degrading bacteria from contaminated soil and characterize the metabolites formed and the genes involved in the degradation pathway. METHODS AND RESULTS: A bacterial strain Xanthomonas sp. ICH12, capable of biodegrading gamma- HCH was isolated from HCH-contaminated soil. DNA-colony hybridization method was employed to detect bacterial populations containing specific gene sequences of the gamma-HCH degradation pathway. linA (dehydrodehalogenase), linB (hydrolytic dehalogenase) and linC (dehydrogenase) from a Sphingomonas paucimobilis UT26, reportedly possessing gamma-HCH degradation activity, were used as gene probes against isolated colonies. The isolate was found to grow and utilize gamma-HCH as the sole carbon and energy source. The 16S ribosomal RNA gene sequence of the isolate resulted in its identification as a Xanthomonas species, and we designated it as strain ICH12. During the degradation of gamma-HCH by ICH12, formation of two intermediates, gamma-2,3,4,5,6-pentachlorocyclohexene (gamma-PCCH), and 2,5-dichlorobenzoquinone (2,5-DCBQ), were identified by gas chromatography-mass spectrometric (GC-MS) analysis. While gamma-PCCH was reported previously, 2,5-dichlorohydroquinone was a novel metabolite from HCH degradation. CONCLUSIONS: A Xanthomonas sp. for gamma-HCH degradation from a contaminated soil was isolated. gamma-HCH was utilized as sole source of carbon and energy, and the degradation proceeds by successive dechlorination. Two degradation products gamma-PCCH and 2,5-DCBQ were characterized, and the latter metabolite was not known in contrasts with the previous studies. The present work, for the first time, demonstrates the potential of a Xanthomonas species to degrade a recalcitrant and widespread pollutant like gamma-HCH. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates the isolation and characterization of a novel HCH-degrading bacterium. Further results provide an insight into the novel degradation pathway which may exist in diverse HCH-degrading bacteria in contaminated soils leading to bioremediation of gamma-HCH.     

Isolation and characterization of some moderately halophilic bacteria with lipase activity

Lipases are an important class of enzymes which catalyze the hydrolysis of long chain triglycerides and constitute the most prominent group of biocatalysts for biotechnological applications. There are a number of lipases, produced by some halophilic microorganisms. In this study, some lipase producing bacteria from the Maharla salt lake located in south of Iran were isolated. All isolates were screened for true lipase activity on plates containing olive oil. The lipase activity was measured using titrimetric methods. Among thirty three isolates, thirteen strains demonstrating orange zone around colonies under UV light, were selected for identification using the molecular methods and some morphological characteristics. The bacterium Bacillus vallismortis BCCS 007 with 3.41 ± 0.14 U/mL lipase activity was selected as the highest lipase producing isolate. This is the first report of isolation and molecular identification of lipase producing bacteria from the Maharla lake.     

Identification and characterization of chlorpyrifos-methyl and 3,5,6-trichloro-2-pyridinol degrading Burkholderia sp. strain KR100

A chlorpyrifos-methyl (CM) degrading bacterium (designated strain KR100) was isolated from a Korean rice paddy soil and was further tested for its sensitivity against eight commercial antibiotics. Based on morphological, biochemical, and molecular characteristics, this bacterium showed greatest similarity to members of the order Burkholderiales and was shown to be most closely related to members of the Burkholderia cepacia group. Strain KR100 hydrolyzed CM to 3,5,6-trichloro-2-pyridinol (TCP) and utilized TCP as the sole source of carbon for its growth. The isolate was also able to degrade chlorpyrifos, dimethoate, fenitrothion, malathion, and monocrotophos at 300 μg/ml but diazinon, dicrotophos, parathion, and parathion-methyl at 100 μg/ml. The ability to degrade CM was found to be encoded on a single plasmid of ~50 kb, pKR1. Genes encoding resistance to amphotericin B, polymixin B sulfate, and tetracycline were also located on the plasmid. This bacterium merits further study as a potential biological agent for the remediation of soil, water, or crop contaminated with organophosphorus compounds because of its greater biodegradation activity and its broad specificity against a range of organophosphorus insecticides.     

Optimization of <Emphasis Type="Italic">Enterobacter cloacae</Emphasis> (KU923381) for diesel oil degradation using response surface methodology (RSM)

Efficiency of Enterobacter cloacae KU923381 isolated from petroleum hydrocarbon contaminated soil was evaluated in batch culture and bioreactor mode. The isolate were screened for biofilm formation using qualitative and quantitative assays. Response surface methodology (RSM) was used to study the effect of pH, temperature, glucose concentration, and sodium chloride on diesel degradation. The predicted values for diesel oil degradation efficiency by the statistical designs are in a close agreement with experimental data (R ² = 99.66%). Degradation efficiency is increased by 36.78% at pH = 7, temperature = 35°C, glucose = 5%, and sodium chloride concentration = 5%. Under the optimized conditions, the experiments were performed for diesel oil degradation by gas chromatographic mass spectrometric analysis (GC-MS). GC-MS analysis confirmed that E. cloacae had highly degrade hexadecane, heptadecane, tridecane, and docosane by 99.71%, 99.23%, 99.66%, and 98.34% respectively. This study shows that rapid bioremoval of hydrocarbons in diesel oil is acheived by E. cloacae with abet of biofilm formation. The potential use of the biofilms for preparing trickling filters (gravel particles) for the degradation of hydrocarbons from petroleum wastes before their disposal in the open environment is highly suggested. This is the first successful attempt for artificially establishing petroleum hydrocarbon degrading bacterial biofilm on solid substrates in bioreactor.     

Isolation and application of Gordonia sp. JC11 for removal of boat lubricants

Boat lubricants are continuously released into the marine environment and thereby cause chronic oil pollution. This study aims to isolate lubricant-degrading microorganisms from Thai coastal areas as well as to apply a selected strain for removal of boat lubricants. Ten microorganisms in the genera of Gordonia, Microbacterium, Acinetobacter, Pseudomonas, Brucella, Enterococcus and Candida were initially isolated by crude oil enrichment culture techniques. The lubricant-removal activity of these isolates was investigated with mineral-based lubricants that had been manufactured for the 4-stroke diesel engines of fishing boats. Gordonia sp. JC11, the most effective strain was able to degrade 25-55% of 1,000 mg L(-1) total hydrocarbons in six tested lubricants, while only 0-15% of the lubricants was abiotically removed. The bacterium had many characteristics that promoted lubricant degradation such as hydrocarbon utilization ability, emulsification activity and cell surface hydrophobicity. For bioaugmentation treatment of lubricant contaminated seawater, the inoculum of Gordonia sp. JC11 was prepared by immobilizing the bacterium on polyurethane foam (PUF). PUF-immobilized Gordonia sp. JC11 was able to remove 42-56% of 100-1,000 mg L(-1) waste lubricant No. 2 within 5 days. This lubricant removal efficiency was higher than those of free cells and PUF without bacterial cells. The bioaugmentation treatment significantly increased the number of lubricant-degrading microorganisms in the fishery port seawater microcosm and resulted in rapid removal of waste lubricant No. 2.     

Isolation and identification of crude oil-degrading yeast strains from Khafji oil field,saud Arabia

Twenty five yeasts isolated were isolated from Khurais oil field in Saudi Arabia and assayed to evaluate their biodegradability. Only five isolates (namely, A1, A2, A3, A4 and A5) showed potential use of oil as sole carbon source. During incubation period, highest growth rate were recorded for A1, A2 and A3 isolates. Low growth distinguished A4 isolate; A5 isolate could not degrade oil.Spectrophotometrical analysis for four yeast isolates biodegradation activities indicated that, A1 isolate was superior for oil degradation (61%) comparing with A4 isolate which reflected lowest degradation % (33%). A2 and A3 isolates showed moderate biodegradation activity (56 and 51% respectively).D1/D2 domain of the 26S rRNA gene sequence was used as molecular marker to identify five yeast isolates. After comparing 26S rRNA gene sequences of five yeast isolates with highly similarity isolates, five yeast isolates (A1, A2, A3, A4 and A5)were submitted to database as Candida tropicalis (MW488263), Candida tropicalis (MW488264), Rhodotorula mucilaginosa (MW488265) and Rhodosporidium toruloides (MW488266) respectively. Using OXF1/ACR1 primer, specific lipase gene amplicon with 250 bp were detected with in all four yeast isolates.     

The characterization of oil-degrading microorganisms from lubricating oil contaminated (scale) soil

AIMS: To isolate and characterize oil-degrading microorganisms from contaminated (scale) soil. METHODS AND RESULTS: Oil-degrading microorganisms were isolated from enrichment cultures of scale soil. Each isolate was identified using 16S rDNA gene and oil degradability was determined on both unused and used lubricating oil. The weight of the extracted remaining oil revealed that most isolates degraded unused lubricating oil more than used lubricating oil. Chemical composition of oil analysed by TLC-FID and GC-MS demonstrated that Nocardia simplex W9 degraded used oil the best, and resulted in a decrease in saturates, aromatics and resins to 52.46, 38.13 and 18.81%, respectively. CONCLUSIONS:Nocardia simplex W9 is the best degrader, among all the isolates, on both used and unused lubricating oil. SIGNIFICANCE AND IMPACT OF THE STUDY: The presence of Nocardia simplex W9 in scale soil enables iron to be recycled by biodegradation.