A novel monocyte differentiation pattern in pristane-induced lupus with diffuse alveolar hemorrhage.

Pristane causes chronic peritoneal inflammation resulting in lupus, which in C57BL/6 mice is complicated by lung microvascular injury and diffuse alveolar hemorrhage (DAH). Mineral oil (MO) also causes inflammation, but not lupus or DAH. Since monocyte depletion prevents DAH, we examined the role of monocytes in the disease. Impaired bone marrow (BM) monocyte egress in Ccr2-/- mice abolished DAH, confirming the importance of monocyte recruitment to the lung. Circulating Ly6Chi monocytes from pristane-treated mice exhibited increased annexin-V staining in comparison with MO-treated controls without evidence of apoptosis, suggesting that pristane alters the distribution of phosphatidylserine in the plasma membrane before or shortly after monocyte egress from the BM. Plasma membrane asymmetry also was impaired in Nr4a1-regulated Ly6Clo/- 'patrolling' monocytes, which are derived from Ly6Chi precursors. Patrolling Ly6Clo/- monocytes normally promote endothelial repair, but their phenotype was altered in pristane-treated mice. In contrast to MO-treated controls, Nr4a1-regulated Ly6Clo/- monocytes from pristane-treated mice were CD138+, expressed more TremL4, a protein that amplifies TLR7 signaling, and exuberantly produced TNFα in response to TLR7 stimulation. TremL4 expression on these novel CD138+ monocytes was regulated by Nr4a1. Thus, monocyte CD138, high TremL4 expression, and annexin-V staining may define an activated/inflammatory subtype of patrolling monocytes associated with DAH susceptibility. By altering monocyte development, pristane exposure may generate activated Ly6Chi and Ly6Clo/- monocytes, contributing to lung microvascular endothelial injury and DAH susceptibility.

Effect of docosahexaenoic acid as a chemopreventive agent on experimentally induced hamster buccal pouch carcinogenesis.

PURPOSE: The current study was directed to investigate the effectiveness of docosahexaenoic acid (DHA) as a chemopreventive agent on experimentally induced hamster buccal pouch (HBP) carcinogenesis. MATERIAL AND METHODS: In this study we used 40 Syrian male hamsters, five weeks old, were divided into 4 groups (GI, GII, GIII, and GIV) of 10 animals in each as follows, GI: Topical application of liquid paraffin alone (thrice a week for 14 weeks), GII: Topical application of 7, 12 dimethyl benz[a]anthracene (DMBA) alone (0.5% in liquid paraffin, thrice a week for 14 weeks), GIII: Topical application of DMBA (0.5% in liquid paraffin, thrice a week for 14 weeks) + Oral administration of DHA (125 mg/kg b.w. in 1 ml distilled water by oral gavage, thrice a week for 14 weeks on alternative days of DMBA application), GIV: Oral administration of DHA alone (125 mg/kg b.w. in 1 ml distilled water by oral gavage, thrice a week for 14 weeks). RESULTS: Gross observations and histopathological findings revealed that, in GI: normal stratified squamous epithelium, in GII: well and moderately differentiated squamous cell carcinoma (SCC), in GIII: variable results ranges from hyperkeratosis, hyperkeratosis and focal hyperplasia, mild dysplasia, and well differentiated SCC with superficial invasion of tumor cells not extended to deeper areas, while in GIV: normal similar to GI. Immunohistochemical results indicated that oral DHA treatment to DMBA treated hamsters restored the normal expression of bcl-2. CONCLUSION: Our results indicated that DHA has the potential to be a dietary chemopreventive agent due to its capacity to improve carcinogen detoxification and to block/suppress the initiation and promotion stages of experimentally produced HBP carcinogenesis.

GTL synthetic paraffin oil shows low liver and tissue retention compared to mineral oil.

Oral exposure to mineral oil may result in a narrow fraction of mineral oil saturated hydrocarbon (MOSH) being retained in tissues. Excess of MOSH hepatic retention may lead to the formation of lipogranuloma caused by predominantly multiring cycloalkanes (naphthenics) in a critical range of C25-C35. Although hepatic lipogranuloma is of low pathological concern, MOSH tissue deposition could be minimized by using an oil of similar quality but devoid of naphthenic structures to decrease hepatic retention. Synthetic Gas to liquid (GTL) oils offer an alternative to petroleum derived mineral oils, because they do not contain naphthenic structures. To demonstrate this point, SD rats were fed either GTL oil (99% iso-alkanes) or naphthenic mineral oil (84% cycloalkanes) at 200 mg/kg bw/day for 90 or 134 days with a recovery group. Liver, fat and mesenteric lymph nodes were analyzed for alkane sub-type levels using Online-HPLC-GC-FID and GCxGC-TOF-MS. Results indicate that at equal external dose, GTL hydrocarbons result in lower tissue levels and more rapid excretion than MOSH. GTL retained hepatic fractions were also qualitatively different than MOSH constituents. Because chemical composition differences, GTL oil show low absorption and tissue retention potential and thus an advantageous alternative to conventional mineral oil.

Ricinus communis as a phytoremediator of soil mineral oil: morphoanatomical and physiological traits.

Rapid growth in the oil industry has been accompanied concomitant increases in risks of spills or leaks triggered by natural or anthropogenic causes that cause soil changes and plant damage. Bio-scavenging and phytoremediation plants are important tools for identifying pollutants and mitigating environmental damage. The objective of this study was to evaluate the phytoremediation potential of Ricinus communis cultivated in soils contaminated with mineral oil, and to determine the possible visual, anatomical and physiological effects. R. communis seeds were pre-germinated in individual pots containing Red Latosol contaminated with Lubrax Essential SL (15W-40) mineral oil at concentrations of 0 (control), 5, 10, and 15 g kg-1. After exposure to treatments, emergency evaluations were performed, and after 45 days of cultivation, visual, morphoanatomical, physiological and oil removal effects were evaluated. There was no difference in emergence showed between treatments. Visual effects were characterized by necrosis and chlorosis formation in R. communis, evidenced on the 45th day of cultivation in all treatments tested, followed by parenchymal tissue alterations with collapsed cell formation and damage to photosynthesis with increasing doses. We found that R. communis removed up to 81% of hydrocarbons in soils, classifying it as potential phytoremediator of contaminated soils. The strong correlation between the variables suggests that R. communis can be used as an indicator of pollutant action.

Confocal Raman Spectroscopy as a tool to measure the prevention of skin penetration by a specifically designed topical medical device.

BACKGROUND/AIM: The scope of this study was to utilize confocal Raman spectroscopy in the evaluation of the degree of non-penetration into the viable skin layers of a paraffin and petrolatum-based product for use in the intimate areas of the skin. The formulation was purposely designed with properties to prevent undesirable skin penetration. METHODS: Product-The test product was a proprietary topical medical device comprising paraffinum liquidum, petrolatum, paraffin, and tocopheryl acetate. Volunteers-A total of 20 healthy volunteers were recruited onto the study-17 females and three males. Product Testing-Raman spectra were obtained at Baseline and 90 minutes after product application. Product Penetration-Skin penetration was calculated from Raman spectra taken at skin depths of -5, 0, 5, 10, 15, and 20 µm. RESULTS: Raman spectra of the investigated product could be clearly differentiated from the skin spectrum. The minimum measurable concentration of the test product was determined at a detection level of 0.5%. In this study, the test product did not penetrate down to skin depths of 10 to 20 µm. CONCLUSIONS: Within the precision range of the test method, the investigated product did not penetrate into the compact part of the stratum corneum. The study revealed Raman spectroscopy to be suitable to detect not only penetration but also non-penetration of substances into human skin.

Toxic effects of mineral oil saturated hydrocarbons (MOSH) and relation to accumulation in rat liver.

Humans are daily exposed to mineral oil saturated hydrocarbons (MOSH) from the diet. We exposed female Fischer 344 rats to a broad mixture and sub-fractions of MOSH. Chemical characterization of the MOSH mixture used and material accumulated in rat tissues were previously reported. Rats were exposed to feed containing 0-4000 mg/kg broad MOSH mixture for 30, 60, 90 and 120 days; and for 120 days to feed containing different MOSH fractions: i) mainly molecular masses < C25 (S-C25), ii) dewaxed, mainly molecular masses > C25 (L-C25) and iii) the L-C25 fraction mixed with wax largely consisting of n-alkanes > C25 (L-C25W). Treatments related effects were increased liver and spleen weight, as well as vacuolization and granuloma formation with lymphoid cell clusters in the liver, but effects varied strongly between the MOSH fractions tested. We conclude that increased liver and spleen weights were mainly related to accumulated iso-alkanes and substituted cycloalkanes, but also wax n-alkanes. Induction of liver granuloma appeared to be related to n-alkanes > C25 and not to the accumulated amount of MOSH. Immune responses to an injected antigen were not affected. MOSH fractions associated with increased liver and spleen weights were similar to those accumulating in humans.

Cosmetic Cleansing Oil Absorption by Soft Contact Lenses in Dry and Wet Conditions.

OBJECTIVES: Previous reports showed that cosmetic cleansing oil for removing makeup, which contains mineral oil and surfactant, can deform some silicone hydrogel contact lenses (SHCLs) when applied directly to the lenses, although plasma-coated SHCLs (lotrafilcon A and B) were not affected. In the present study, we investigated hydrogel lenses and SHCLs in both wet and dry conditions. METHODS: Several brands of hydrogel and SHCLs were immersed in a cleansing oil solution containing Sudan Black B for 5 min under wet and dry conditions. The lenses under the wet condition were simply picked up from the saline, whereas those under the dry condition were blotted with paper wipes. After immersing, the excess solution remaining on the lenses was removed by finger rubbing with a multipurpose solution. The lenses were then examined using a stereomicroscope, and their mean brightness was measured and compared. RESULTS: The cosmetic cleansing oil was not absorbed by the hydrogel lenses under wet or dry conditions. However, four of seven brands of SHCLs absorbed the cosmetic cleansing oil under both conditions (dry and wet), whereas asmofilcon A absorbed it only under the dry condition. Lotrafilcon B and delefilcon A did not absorb cleansing oil even under the dry condition. CONCLUSIONS: Hydrogel lenses resist cosmetic cleansing oil. However, SHCLs have different degrees of resistance depending on the lens material. Some SHCLs absorbed cosmetic cleansing oil more under dry conditions than under wet conditions.

Brazilian Cerrado soil reveals an untapped microbial potential for unpretreated polyethylene biodegradation.

Discarded PE-based products pose a social and environmental threat because of their recalcitrance to degradation, a consequence of the unique set of PE's physicochemical properties. In this study we isolated nine novel PE-degrading bacteria from plastic debris found in soil of the savanna-like Brazilian Cerrado. These bacterial strains from the genera Comamonas, Delftia, and Stenotrophomonas showed metabolic activity and cellular viability after a 90-day incubation with PE as the sole carbon source. ATR/FTIR indicated that biodegraded PE undergone oxidation, vinylene formation, chain scission, among other chemical changes. Considerable nanoroughness shifts and vast damages to the micrometric surface were confirmed by AFM and SEM. Further, phase imaging revealed a 46.7% decrease in the viscous area of biodegraded PE whereas Raman spectroscopy confirmed a loss in its crystalline content, suggesting the assimilation of smaller fragments. Intriguingly, biodegraded PE chemical fingerprint suggests that these strains use novel biochemical strategies in the biodegradation process. Our results indicate that these microbes are capable of degrading unpretreated PE of very high molecular weight (191,000gmol-1) and survive for long periods under this condition, suggesting not only practical applications in waste management and environmental decontamination, but also future directions to understand the unraveled metabolism of synthetic polymers.

Shared Physiological Traits of Exophiala Species in Cold-Blooded Vertebrates, as Opportunistic Black Yeasts.

Several species of the genus Exophiala are found as opportunistic pathogens on humans, while others cause infections in cold-blooded waterborne vertebrates. Opportunism of these fungi thus is likely to be multifactorial. Ecological traits [thermotolerance and pH tolerance, laccase activity, assimilation of mineral oil, and decolorization of Remazol Brilliant Blue R (RBBR)] were studied in a set of 40 strains of mesophilic Exophiala species focused on the salmonis-clade mainly containing waterborne species. Thermophilic species and waterborne species outside the salmonis-clade were included for comparison. Strains were able to tolerate a wide range of pHs, although optimal growth was observed between pH 4.0 and 5.5. All strains tested were laccase positive. Strains were able to grow in the presence of the compounds (mineral oil and RBBR) with some differences in assimilation patterns between strains tested and also were capable of degrading the main chromophore of RBBR. The study revealed that distantly related mesophilic species behave similarly, and no particular trend in evolutionary adaptation was observed.

Waste lubricating oil removal in a batch reactor by mixed bacterial consortium: a kinetic study.

The growth kinetics and biodegradation of two waste lubricating oil samples including waste engine oil (WEO) and waste transformer oil (WTO) were studied using pure isolates and mixed culture of Ochrobactrum sp. C1 and Bacillus sp. K1. The mixed culture significantly influenced degradation efficiency of the pure isolates through bioaugmentation process. In particular, the mixed culture was capable of growing on various n-alkanes and polycyclic aromatic hydrocarbons and was able to tolerate unusually high concentrations of waste lubricants (WEO-86.0 g/L and WTO-81.5 g/L). The initial concentration of waste lubricating oils has been varied in the range of 1-10 % (v/v). Under this experimental range, the bacterial growth has been observed to follow Haldane-type kinetics characterizing the presence of substrate inhibition. Haldane model was used to fit the exponential growth data and the following kinetic parameters were obtained: µ max = 0.078 h(-1), K S = 23.101 g/L, K i = 43.844 g/L for WEO; and µ max = 0.044 h(-1), K S = 10.662 g/L, K i = 58.310 g/L for WTO. The values of intrinsic kinetic parameters, like specific growth rate µ max, half saturation constant, K S, inhibition constant, K i and the maximum substrate concentration, S max and growth yield coefficient Y x/s , have been determined using each model hydrocarbon and their mixture as limiting substrate. Relative changes in the values of the kinetic parameters have been correlated to the number of carbon atoms present in n-alkanes. The metabolites from degradation of model hydrocarbon compounds have been identified by GC-MS to elucidate the possible pathway of waste lubricating oil degradation process.

Mineral oil in human tissues, part II: characterization of the accumulated hydrocarbons by comprehensive two-dimensional gas chromatography.

Mineral oil hydrocarbons are by far the largest contaminant in the human body. Their composition differs from that in the mineral oils humans are exposed to, and varies also between different tissues of the same individual. Using the presently best technique for characterizing the composition of mineral oil hydrocarbons, comprehensive two-dimensional gas chromatography (GC×GC), the hydrocarbons in human tissues were compared to those of various mineral oils. This provided information about the strongly accumulated species and might give hints on the flow path through the human body. The selectivity of accumulation is probably also of interest for the risk assessment of synthetic hydrocarbons (polyolefins). GC×GC grouped the MOSH into classes of n-alkanes, paraffins with a low degree of branching, multibranched paraffins and naphthenes (alkylated cyclic hydrocarbons) with 1-4 rings. Metabolic elimination was observed for constituents of all these classes, but was selective within each class. The MOSH in the subcutaneous abdominal fat tissues and the mesenteric lymph nodes (MLN) had almost the same composition and included the distinct signals observed in mineral oil, though in reduced amounts relative to the cloud of unresolved hydrocarbons. The MOSH in the liver and the spleen were different from those in the MLN and fat tissue, but again with largely identical composition for a given individual. Virtually all constituents forming distinct signals were eliminated, leaving an unresolved residue of highly isomerized hydrocarbons.

"V-junction": a novel structure for high-speed generation of bespoke droplet flows.

We present the use of microfluidic "V-junctions" as a droplet generation strategy that incorporates enhanced performance characteristics when compared to more traditional "T-junction" formats. This includes the ability to generate target-sized droplets from the very first one, efficient switching between multiple input samples, the production of a wide range of droplet sizes (and size gradients) and the facile generation of droplets with residence time gradients. Additionally, the use of V-junction droplet generators enables the suspension and subsequent resumption of droplet flows at times defined by the user. The high degree of operational flexibility allows a wide range of droplet sizes, payloads, spacings and generation frequencies to be obtained, which in turn provides for an enhanced design space for droplet-based experimentation. We show that the V-junction retains the simplicity of operation associated with T-junction formats, whilst offering functionalities normally associated with droplet-on-demand technologies.

[MICROBIAL DESTRUCTION MINERAL (OIL) MOTOR OIL].

In a review information is presented about composition of mineral motor oils and their negative impact on the environment and the ability of microorganisms, in particular actinobacteria, to assimilate hydrocarbon oil components. The role of bacteria is described in the process of cleaning up polluted environments motor oils and the prospect of their use in biotechnology, environmental clean-up of these pollutants.

Production and properties of a surface-active lipopeptide produced by a new marine Brevibacterium luteolum strain.

Microbial-derived surfactants are molecules of great interest due to their environmentally friendly nature and low toxicity; however, their production cost is not competitive when compared to synthetics. Marine microorganisms are exposed to extremes of pressure, temperature, and salinity; hence, they can produce stable compounds under such conditions that are useful for industrial applications. A screening program to select marine bacteria able to produce biosurfactant using low-cost substrates (mineral oil, sucrose, soybean oil, and glycerol) was conducted. The selected bacterial strain showed potential to synthesize biosurfactants using mineral oil as carbon source and was identified as Brevibacterium luteolum. The surface-active compound reduced the surface tension of water to 27 mN m(-1) and the interfacial tension (water/hexadecane) to 0.84 mN m(-1) and showed a critical micelle concentration of 40 mg L(-1). The biosurfactant was stable over a range of temperature, pH, and salt concentration and the emulsification index (E24) with different hydrocarbons ranging from 60 to 79 %. Structural characterization revealed that the biosurfactant has a lipopeptide nature. Sand washing removed 83 % of crude oil demonstrating the potential of the biosurfactants (BS) for bioremediation purposes. The new marine B. luteolum strain showed potential to produce high surface-active and stable molecule using a low-cost substrate.

[Influence of heavy metals on surfactants synthesis by Nocardia vaccinii IMV B-7405].

The production of surfactants by Nocardia vaccinii IMV B-7405 in glycerol -and hydrocarbon-containing medium after addition Cd(3+) Pb(2+) and Cu(2+) was investigated. It was established that the introduction of 0.1 mM Cu(2+) in the exponential growth phase of IMV B-7405 strain or simultaneous addition of Cu(2+) (0.1 mM) and Cd(2+) (0.3 mM), Cu(2+) (0.1 mM) and Pb(2+) (0.3 mM) in stationary phase was accompanied by the increase of conditional concentration of the surfactant (by 53 and 20-26%, respectively) compared with indexes in the medium without metals cations. It was established that the surfactants of N. vaccinii IMV B-7405 possessed protective functions from heavy metals influence. After surfactants elimination the survival of cells of strain IMV B-7405 in the presence of Cu(2+) (1.5-2.5 mM), Cd(2+) or Pb(2+) (0.1-0.3 mM) decreased a few times (to 5-45%). The inhibition action of Cu(2+) on alkane hydroxylase activity (the first enzyme of hydrocarbon catabolism) and stimulation--on phosphoenolpyruvate synthetase (enzyme of surface-active glycolipids biosynthesis) in MB B-7405 have been established.

[Synthesis of surfactants by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 on industrial waste].

The synthesis of surfactants by Rhodococcus erythropolis IMV Ac-5017, Acinetobacter calcoaceticus IMV B-7241 and Nocardia vaccinii IMV B-7405 on industrial waste (food and oil-processing industry, production of biodiesel) was investigated. The possibility of replacing the expensive substrates (n-hexadecane and ethanol) by industrial waste (oil and fat industry, fried sunflower oil, glycerol, liquid paraffin) for the surfactant biosynthesis was established. The conditional concentration of surfactants was maximal on oil containing substrates and exceeded those on n-hexadecane and ethanol 2-3 times. The highest rates of surfactants synthesis were observed on fried sunflower oil with the use of inoculum grown on carbohydrate substrates (glucose, molasses). It was established that the addition of glucose (0.1%) was accompanied by 2-4-fold intensification of surfactants synthesis by R. erythropolis IMV Ac-5017 and N. vaccinii IMV B-7405 on fried sunflower oil (2%).

Mineral oil in human tissues, Part I: concentrations and molecular mass distributions.

Of 37 subjects aged 25-91 y (mean 67 y), mineral oil hydrocarbons were measured in subcutaneous abdominal fat tissue, mesenteric lymph nodes (MLN), spleen, liver and lung, for some of them also in kidney, heart and brain. No mineral oil aromatic hydrocarbons (MOAH) were detected. The mean concentration of mineral oil saturated hydrocarbons (MOSH) in the mesenteric lymph nodes was 223 mg/kg, in liver 131 mg/kg, in fat tissue 130 mg/kg, in spleen 93 mg/kg and in lung 12 mg/kg. They were clearly lower in kidney, heart and brain. The maxima, found in MLN and spleen, were 1390 and 1400 mg/kg, respectively. For a quarter of the subjects a total amount of MOSH in the body above 5 g was calculated. The MOSH composition in the fat tissue and the MLN appeared virtually identical and varied little between the subjects. It was centered on the n-alkanes C23-C24, ranged from C16 to C35 and included hydrocarbons of plant origin. The MOSH in spleen and liver had almost the same composition for a given subject, but varied somewhat between subjects. They were centered between C25 and C27, ranged from C18 to beyond C45 and were without hydrocarbons of plant origin. Part of the MOSH seem to be strongly accumulated, resulting in far higher concentrations in human tissues related to exposure than observed in shorter term animal experiments. The composition of the accumulated MOSH does not support that Class I mineral oils, sometimes termed "food grade", are less accumulated in the human body than Class II and III oils, which questions the present classification.

Quantification of mineral oil accumulation and movement in potato plants and its significance in potato virus Y management.

BACKGROUND: Mineral oils are increasingly sprayed to manage potato virus Y (PVY). However, the mode of accumulation and movement of mineral oil in the potato plant has not been understood. This information is important for optimisation of the concentration and frequency of spraying. During the 2012 season, cvs Russet Burbank and Shepody were planted in the field and in the greenhouse, respectively, and were subjected to mineral oil treatments. The plant samples from the treatment plots were collected, and oil was extracted and quantified using gas chromatography-mass spectrometry. RESULTS: Mineral oil stayed in the vicinity of the sprayed leaves and did not move from leaflet to leaflet or from leaflet to stem, stolon, tuber or root. Following spraying, the oil content in the plant leaves diluted as time progressed. At plant maturity, leaves sampled from the greenhouse sprayed plants had about 4 times more oil content than those sampled from the field sprayed plants. Plots treated with regular spray of mineral oil showed low PVY incidences at crop harvest. CONCLUSION: The information generated in this study on the pattern of accumulation and movement of mineral oil in greenhouse- and field-grown potato plants shows that, as the oil does not move from leaflet to leaflet, frequent mineral oil sprays from crop emergence to harvest are required to prevent PVY infection in newly emerged leaflets and seasonal spread of PVY. The frequency of sprays may be kept higher from early to mid-stage, when plant growth is faster, and lower close to plant maturity.

In vitro-in vivo correlation in skin permeation.

PURPOSE: In vitro skin permeation studies have been used extensively in the development and optimisation of delivery of actives in vivo. However, there are few reported correlations of such in vitro studies with in vivo data. The aim of this study was to investigate the skin permeation of a model active, niacinamide, both in vitro and in vivo. METHODS: Conventional diffusion cell studies were conducted in human skin to determine niacinamide permeation from a range of vehicles which included dimethyl isosorbide (DMI), propylene glycol (PG), propylene glycol monolaurate (PGML), N-methyl 2-pyrrolidone (NMP), Miglyol 812N® (MG), and mineral oil (MO). Single, binary or ternary systems were examined. The same vehicles were subsequently examined to investigate niacinamide delivery in vivo. For this proof-of-concept study one donor was used for the in vitro studies and one volunteer for the in vivo investigations to minimise biovariability. Analysis of in vitro samples was conducted using HPLC and in vivo uptake of niacinamide was evaluated using Confocal Raman spectroscopy (CRS). RESULTS: The amount of niacinamide permeated through skin in vitro was linearly proportional to the intensity of the niacinamide signal determined in the stratum corneum in vivo. A good correlation was observed between the signal intensities of selected vehicles and niacinamide signal intensity. CONCLUSIONS: The findings provide further support for the use of CRS to monitor drug delivery into and across the skin. In addition, the results highlight the critical role of the vehicle and its disposition in skin for effective dermal delivery.

[Microbial potential for cleaning the oiled iron scale].

The possibility of using microorganisms to clean oiled iron scale of metallurgical production was investigated with the goal of recuperation. A stable microbial association growing on mineral oil as the sole carbon source was isolated from a sample from oiled iron scale taken directly from a metallurgical plant. For microbial cultures isolated from this association, the taxonomic position, as well as their morphological and cultural characteristics, were determined. The microorganisms belonged to the genera Luteimonas, Alcanivorax, Flavobacterium, and Pseudomonas. Microbial associations oxidizing mineral oil were found to contain some microorganisms incapable of its utilization, which stimulated the hydrocarbon-oxidizing microflora. Application of the isolates, as well as of the strains from microbial collections, resulted in a 58% decrease in residual oil content in treated samples of the oiled iron scale.