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Rationale: Discovering biomarkers of major depressive disorder (MDD) can give a deeper understanding of this mood dis order and improve the ability to screen for, diagnose, and treat MDD. Objectives: In this study, metabolomics was used in unraveling metabolite fuctuations of MDD and drug outcome by creating specifc metabolomic fngerprints. We report metabolomic patterns of change of the hippocampus of adult male Wistar rats following chronic social isolation (CSIS) (6 weeks), an animal model of depression, and/or chronic tianeptine (Tian) treatment (10 mg kg−1 per day) (lasting 3 weeks of 6-week CSIS), monitored by using comprehensive GC×GC–MS. Results: The comparative metabolomic analysis highlighted the role of gamma aminobutyric acid (GABA), iso-allocholate, and unsaturated fatty acid metabolism alterations following the CSIS, which was corroborated with moderate to strong nega tive Pearson’s correlation of GABA, docosahexaenoic, 9-hexadecenoic acid, 5,8,11,14-eicosatetraynoic, and arachidonic acids with immobility behavior in the forced swim test. The antidepressant efect of Tian restored GABA levels, which was absent in Tian resilient rats. Tian decreased myo-inositol and increased TCA cycle intermediates, amino acids, and cholesterol and its metabolite. As key molecules of divergence between Tian efectiveness and resilience, metabolomics revealed myo-inositol, GABA, cholesterol, and its metabolite. A signifcant moderate positive correlation between myo-inositol and immobility was revealed. Tian probably acted by upregulating NMDAR’s and α2 adrenergic receptors (AR) or norepinephrine transporter in both control and stressed animals. Conclusion: Metabolomics revealed several dysregulations underlying CSIS-induced depressive-like behavior and responsiveness to Tian, predominantly converging into NMDAR-mediated glutamate and myo-inositol signalization and GABA inhibitory pathways.

The increased commercial use and spread of nanoceria raises concerns about the risks associated with its effects on living organisms. Although Pseudomonas aeruginosa may be ubiquitous in nature, it is largely found in locations closely linked with human activity. P. aeruginosa san ai was used as a model organism for a deeper understanding of the interaction between biomolecules of the bacteria with this intriguing nanomaterial. A comprehensive proteomics approach along with analysis of altered respiration and production of targeted/specific secondary metabolites was conducted to study the response of P. aeruginosa san ai to nanoceria. Quantitative proteomics found that proteins associated with redox homeostasis, biosynthesis of amino acids, and lipid catabolism were upregulated. Proteins from outer cellular structures were downregulated, including transporters responsible for peptides, sugars, amino acids and polyamines, and the crucial TolB protein of the Tol-Pal system, required for the structural formation of the outer membrane layer. In accordance with the altered redox homeostasis proteins, an increased amount of pyocyanin, a key redox shuttle, and the upregulation of the siderophore, pyoverdine, responsible for iron homeostasis, were found. Production of extracellular molecules, e.g. pyocyanin, pyoverdine, exopolysaccharides, lipase, and alkaline protease, was significantly increased in P. aeruginosa san ai exposed to nanoceria. Overall, nanoceria at sublethal concentrations induces profound metabolic changes in P. aeruginosa san ai and provokes increased secretion of extracellular virulence factors, revealing the powerful influence this nanomaterial has on the vital functions of the microorganism. © 2023 Informa UK Limited, trading as Taylor & Francis Group.

Literature data about semi-volatile organic compounds in plants and the effect of cerium oxide nanoparticles on them are scarce. Surface modification of nanoparticles may change nanoparticle-environment interaction, and therefore affects compounds in plants. In this research, uncoated and glucose-, levan-, and pullulan-coated cerium oxide nanoparticles were used for wheat and pea treatment during the growth. The aim was the screening of semi-volatile organic compounds from plants’ shoots using comprehensive two-dimensional gas chromatography–mass spectrometry, a powerful separation technique allowing to reach unique separation resolution, and investigation of qualitative changes after the treatment with coated cerium oxide nanoparticles. The results were analyzed by the identification of individual peaks and fingerprint analysis by image processing. Wheat samples contained a higher number of semi-volatile organic compounds (108) compared to pea (77) but were less affected by the treatments with coated nanoparticles. The highest number of compounds was detected in wheat after the treatment with levan- and pullulan-coated nanoparticles, and in pea after treatment with levan-coated nanoparticles. This article reports a successful application of a semi-volatile organic compounds profile presented only as categorical variables and unique fingerprint images for the inter-cultivar recognition. This method may be useful in screening nanoparticles’ effects on different plants. Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4520]

The Indus-Ganga-Brahmaputra River Basin (IGBRB) is a trans-boundary river basin flowing through four major countries in South Asia viz. India, Pakistan, Bangladesh, and Nepal. Contamination of surface water by untreated or inadequately treated wastewater has been a huge problem for pathogenic microorganisms in economies in transition. Recent studies have reported that sewage surveillance can provide prior information of the outbreak data, because faeces can contain the novel coronavirus (SARS-CoV-2) shed by infected humans. Hence, in this study we have geo-spatially mapped the COVID-19 hotspots during the peak time in the first and second wave of pandemic to demonstrate the need and usefulness of wastewater surveillance strategy in IGBRB during ongoing pandemic. Further we discussed the status of sanitation, health and hand-hygiene in the IGBRB along with characterization of the challenges posed by the pandemic in achieving the United Nations Sustainable Development Goals (UN-SDGs). Monthly Geographical Information System (GIS) mapping of COVID-19 hotspots in the IGBRB showed an increase in the spread along the direct sewage discharge points. The social inequalities expose the vulnerabilities of the urban poor in terms of the burden, risks and access to Water, Sanitation, and Hygiene (WASH) needs. Such an evidence-based image of the actual SARS-CoV-2 viral load in the community along the IGBRB can provide valuable insights and recommendations to deal with the future waves of COVID-19 pandemic in this region that can go a long way in achieving the UN-SDGs.

Cerium oxide nanoparticles (nCeO2) have widespread applications, but they can be hazardous to the environment. Some reports indicate the toxic effect of nCeO2 on tested animals, but literature data are mainly contradictory. Coating of nCeO2 can improve their suspension stability and change their interaction with the environment, which can consequently decrease their toxic effects. Herein, the exopolysaccharides levan and pullulan, due to their high water solubility, biocompatibility, and ability to form film, were used to coat nCeO2. Additionally, the monosaccharide glucose was used, since it is a common material for nanoparticle coating. This is the first study investigating the impact of carbohydrate-coated nCeO2 in comparison to uncoated nCeO2 using different model organisms. The aim of this study was to test the acute toxicity of carbohydrate-coated nCeO2 on the bacterium Vibrio fischeri NRRL B-11177, the crustacean Daphnia magna, and zebrafish Danio rerio. The second aim was to investigate the effects of nCeO2 on respiration in Daphnia magna which was performed for the first time. Finally, it was important to see the relation between Ce bioaccumulation in Daphnia magna and Danio rerio and other investigated parameters. Our results revealed that the coating decreased the toxicity of nCeO2 on Vibrio fischeri. The coating of nCeO2 did not affect the nanoparticles’ accumulation/adsorption or mortality in Daphnia magna or Danio rerio. Monitoring of respiration in Daphnia magna revealed changes in CO2 production after exposure to coated nCeO2, while the crustacean's O2 consumption was not affected by any of the coated nCeO2. In summary, this study revealed that, at 200 mg L−1, uncoated and carbohydrate-coated nCeO2 are not toxic for the tested organisms, however, the CO2 production in Daphnia magna is different when they are treated with coated and uncoated nCeO2. The highest production was in glucose and levan-coated nCeO2 according to their highest suspension stability. This is the peer-reviewed version of the article: Milenković I, Radotić K, Despotović J, Lončarević B, Lješević M, Spasić SZ, Nikolić A, Beškoski VP. Toxicity investigation of CeO2 nanoparticles coated with glucose and exopolysaccharides levan and pullulan on the bacterium Vibrio fischeri and aquatic organisms Daphnia magna and Danio rerio. Aquatic Toxicology. 2021;236:105867; [https://doi.org/10.1016/j.aquatox.2021.105867] The published version: [https://cer.ihtm.bg.ac.rs/handle/123456789/4687]

PurposeThe purpose of this paper is to determine the polyphenol content, antioxidative potential and antiproliferative activity of Swiss chard from Montenegro, grown under different irrigation and fertilization regimes.Design/methodology/approachSwiss chard was grown in the open field (Lješkopolje, Montenegro) where it was subjected to different fertilization and irrigation regimes. Chard samples were analyzed for previously identified polyphenols and for antioxidant parameters. Additionally, in order to complete the biological activities, chard extracts were tested for antiproliferative activity against MFC-7 and HT-29 tumor cell lines.FindingsThe polyphenols identified in Swiss chard were flavonoids: vitexin-2?-O-xyloside, vitexin-6?-O-acetyl-2?-O-xyloside, vitexin-6?-O-malonyl-2?-O-xyloside and isorhamnetin-3,7-diglucoside. In the antioxidant tests, DPPH (2,2-diphenyl-1-picrylhydrazyl), and ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)), chard extract had values of 7.00 and 8.50 (mean values) µmol Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) equ/d.w., respectively. The tested chard extracts inhibited cell proliferation at different concentrations (3.125–50.0 µg/mL) against the MCF-7 cell line, after 24 and 48 h of incubation. The antiproliferative activity, expressed in terms of IC50, was 32.97 and 86.45 µg/mL after 24 h of incubation and 20.76 and 23.33 µg/mL after 48 h of incubation, for treated and untreated chard extracts, respectively.Originality/valueThese data suggest Montenegrin Swiss chard grown under different irrigation and fertilization treatments can be considered as a functional food and should be included in an everyday diet. The collected data could help in the growth improvement of chard with functional food properties.

Cilj prikazanog istraživanja je utvrđivanje kvalitativne varijabilnosti i relativne zastupljenosti seskviterpenskih ugljovodonika u uzorcima vrste Teucrium montanum L. prikupljenih sa dva različita tipa podloge. Četiri uzorka etarskih ulja sa serpentinita i četiri sa krečnjaka dobijeno je metodom hidrodestilacije od nadzemnih biljnih delova. Na osnovu rezultata, pokazano je da populacije sa serpentinitskih staništa sintetišu 2 puta više seskviterpena nego sa krečnjačkih, dok je jedinjenje 6-epi-β-kubeben detektovan samo u populacijama sa krečnjaka. Edafske karakteristike staništa utiču na kvalitativni sastav i relativnu zastupljenost seskviterpena u etarskim uljima što ima značajnu primenu u biotehnologiji. The aim of this study is to determine the qualitative variability and relative presence of sesquiterpene hydrocarbons in essential oils samples of Teucrium montanum L. collected from two different substrate types. Four samples of essential oils from serpentinite and four from calcareous were obtained by the method of hydrodistillation from aboveground plant parts. Based on the results, it was shown that populations from serpentinite habitats synthesize 2 times more sesquiterpenes than from calcareous ones, while the compound 6-epi-β-cubeben was detected only in populations from calcareous. Edaphic characteristics of habitats affect the qualitative composition and relative presence of sesquiterpenes in essential oils, which has a significant application in biotechnology.

We describe herein the synthesis and laccase mediated oxidation of six novel 1,4-dihydropyridine (DHP)-based hexahydroquinolines (DHP1-DHP3) and decahydroacridines (DHP4-DHP6). We employed different laccase enzymes with varying redox potential to convert DHP1-DHP3 and DHP4-DHP6 to the corresponding pyridine-containing tetrahydroquinoline and octahydroacridine derivatives, respectively. Intensively coloured products were detected in all biocatalytic reactions using laccase from Trametes versicolor (TvLacc), possibly due to the presence of conjugated chromophores formed in products after oxidation. The NMR assessment confirmed that the oxidation product of DHP1 was its corresponding pyridine-bearing tetrahydroquinoline derivative. Laccase from Bacillus subtillis (BacillusLacc) was the most efficient enzyme for this group of substrates using HPLC assessment. Overall, it could be concluded that DHP2 and DHP5, bearing catecholic structures, were easily oxidized by all tested laccases, while DHP3 and DHP6 containing electron-withdrawing nitro-groups are not readily oxidized by laccases. DHP4 with decahydroacridine moiety consisting of three condensed six-membered rings that contribute not only to the volume but also to the higher redox potential of the substrate rendered this compound not to be biotransformed with any of the mentioned enzymes. Overall, we showed that multiple analytical approaches are needed in order to assess biocatalytical reactions. Supplementary material: [https://cherry.chem.bg.ac.rs/handle/123456789/4568]

BACKGROUND: Pectin is a complex polysaccharide, present in fresh and processed food as an additive, which also serves as an important source of fiber. In this work, the aim was to investigate in-vitro application of apple pectin as a possible antimicrobial, antioxidant and prebiotic agent for growth of bacteria selected from human milk and infant feces, as well as standard strains Lactobacillus rhamnosus and Bifidobacterium bifidum. METHODS : All the bacteria isolated from the milk of mothers of preterm and term-born infants, bacteria from infant feces and standard strains were tested for fermentation of apple pectin as the main carbohydrate in selective broth media. RESULTS: An increase in the growth of bacteria Bifidobacteria, Lactobacillus, and a consortium of bacteria selected from human milk and infant feces was noticed after pectin fermentation. It was found that pectin has a positive impact on the increase of the antioxidant capacity in all the tested samples. A high correlation was achieved, comparing electrochemical with spectrophotometric methods. Antimicrobial tests showed that pectin and fermentation products have slight or no influence at all on the growth of standard strains of Escherichia coli, Staphylococcus aureus and Candida albicans. CONCLUSIONS: The results showed the importance of pectin as an antioxidant and its impact on the development of potential probiotic microbiota in mothers and infants. The study indicated a new potential application of pectin as a supplement in infant food.

The production of levan by Bacillus licheniformis NS032 in a medium based on sugar beet molasses was studied. High polysaccharide yields were produced by using diluted molasses (100–140 g/L of total sugars) with the addition of commercial sucrose up to 200 g/L of total sugars, as well as K2HPO4. A levan yield of 53.2 g/L was obtained on a medium optimized by response surface methodology, containing 62.6% of sugar originating from molasses, and 4.66 g/L of phosphate, with initial pH value of 7.2. In comparison to the media with 200 and 400 g/L sucrose, in the molasses optimized medium, the observed bacterial growth was faster, while the maximum production of polysaccharide was achieved over a shorter time interval (48 h). The polysaccharide produced in molasses medium had a weight average molecular weight of 5.82 × 106 Da, degree of branching 12.68%, viscosity of 0.24 dL/g, and based on methylation analysis and NMR data, it did not significantly differ from levan obtained in the medium with 200 g/L sucrose. © 2018 Elsevier B.V. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/2943] This is peer reviewed version of the following article: Gojgic-Cvijovic, G. D.; Jakovljevic, D. M.; Loncarevic, B. D.; Todorovic, N. M.; Pergal, M. V.; Ciric, J.; Loos, K.; Beškoski, V.; Vrvić, M. M. Production of Levan by Bacillus Licheniformis NS032 in Sugar Beet Molasses-Based Medium. International Journal of Biological Macromolecules 2019, 121, 142–151. [https://doi.org/10.1016/j.ijbiomac.2018.10.019]

Bacillus sp.-based microbial formulations have found wide application in many fields: from pharmacy and medicine to environmental protection and agriculture due to the ability of this species to produce various metabolites and to form endospores. Recently, these products have gained popularity as biopesticidal and phytostimulatory agents, which are a „green“ alternative to overused agrochemicals. In order to obtain a high-quality and long-lasting product with desired characteristics, it is necessary to optimize the production process at each stage, which implies coordinating the microbial species, the type and the conditions of microbial cultivation along with formulation technologies. This paper provides a concise overview of the most important findings in this area, regarding characteristics of microbial formulations and specific criteria that need to be met when such a product is formulated. It should serve as a beginning point for everyone starting new research, not just in the field of biofertilization and biological control of plant diseases, but generally in the field of biochemical engineering. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 43004]

This study aimed to determine the qualitative variability of essential oils of mountain germander – Teucrium montanum L. (Lamiaceae) at the population level, depending on the type of geological substrate. Ten samples of essential oils originated from aerial plant parts of populations from calcareous and ten from serpentinite were tested by GCxGC-MS method. The obtained results showed that the serpentinite populations have more than 3 times higher essential oil yield than calcareous populations. Based on the average values for the relative percentage amounts of T. montanum essential oils, it was shown that the sesquiterpenes (34.89%) are the main compounds in analyzed essential oils. Population from calcareous habitats synthesize twice as many aliphatic hydrocarbons than populations from serpentinite habitats, while populations from serpentinite habitats synthesize twice as much mono- and sesquiterpenes. The compounds with highest relative percentage amounts in calcareous populations was the hydrocarbon tetracosane (9.02%), while in serpentinite populations it was oxygenated sesquiterpene, limonen-10-ol (4.81%). Compounds which were only detected for calcareous populations are: dodecane and isophytol, while for serpentinite populations are: 3-caren-2-ol, carvone oxide and pyronene. The obtained results indicate a significant influence of the habitat geological substrate on the qualitative characteristics of the T. montanum essential oil. Differentiation of calcareous and serpentinite populations into two distinct groups based on the essential oil composition indicate the significant presence of specific chemotypes developed by the influence of various edaphic characteristics.

We developed capillary zone electrophoresis (CZE) with indirect UV detection for the determination of fluoride (F-) in seawater using transient isotachophoresis (tITP) as an on-line concentration procedure. A method of correcting sample salinity effects was also proposed so that F- concentrations were obtained using a calibration graph. The proposed method is simple: it requires no sample pretreatment aside from dilution. The following optimum conditions were established: background electrolyte (BGE), 5 mM 2,6-pyridinedicarboxylic acid (PDC) adjusted to pH 3.5 containing 0.03% m/v hydroxypropyl methylcellulose (HPMC); detection wavelength, 200 nm; vacuum (50 kPa) injection period of sample, 5 s (254 nL); and applied voltage, 23 kV with the sample inlet side as the cathode. The limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) for F- reached 0.024 and 0.070 mg/L, respectively. The respective values of the relative standard deviation (RSD) of the peak area, peak height, and migration time for F- were 2.5, 3.4, and 0.30%. The proposed method was applied for the determination of F- in seawater samples collected from coastal waters of western Japan during August 26-28, 2014. Both results obtained using standard addition method and a calibration graph agreed with those obtained using a conventional spectrophotometric method. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3182]

The aim of this paper was to investigate whether changes in the quantity and structure of humic acids (HA) occur during bioremediation of waste mazute (heavy residual fuel oil). The effects of humification on the structure of HA were evaluated by Fourier Transform Infrared Spectroscopy (FT-IR), potentiometric titrations, the ratio of absorbances at 465 and 665 nm (E4/E6 ratio) and the ratio. Also, the quality of humification was monitored by determining parameters which are important for measuring the evolution of humic substances (HS), such as CHA/CFA (the humic acidifulvic acidratio), the rate of extraction (TE) and the index of polymerization (IP). An increase of the content of HA from 0.23% to 0.70% was observed during the bioremediation process. The FT-IR spectra and 04 ratio of HA extracted at the beginning and the end of the process indicate structural changes during the bioremediation process. The groups containing aromatic and carboxylic carbon increased, resulting in HA structures of higher aromaticity. An increase of the B4/E6 ratio during bioremediation treatment implied the enrichment of HA with functional oxygen groups. Potentiometric titrations of HA solution showed increases in the buffering and the redox capacities of HA during the bioremediation process. The results of parameters of humification showed an increase of the compositional carbon in HA at the end, compared to at the start, of bioremediation, while the carbon that belonged to fulvic acids (FA) reduced by 44%. Transformation into HA is the likely cause of this observed reduction. The TE and the IP demonstrated that humification occured during the bioremediation process. According to the available data, this is the first report on synthesis of HS during bioremediation of petroleum hydrocarbons. (C) 2017 Published by Elsevier Ltd.

Perfluoroalkyl acids (PFAAs) including perfluoroalkyl sulfonates (PFSAs) and perfluoroallcyl carboxylates (PFCAs) were analyzed in sediment samples taken from Ajifu Waterway in Osaka city, from Osaka Bay, and from Kagoshima Bay, as well as in fifteen seawater samples collected from Osaka Bay and coastal waters of Western Japan. In all sediment samples, only PFCAs were detected, and the highest concentration was determined in Ajifu Waterway, where Sigma PFAA was 58990 ng kg(-1) dry weight. The total concentrations of PFAAs in sea water samples ranged between the limit of quantification and 53.4 ng L-1, and perfluorohexanoic acid was the most prevalent and had the highest concentration of 37 ng L-1. The changes in the patterns and concentrations of PFAA5 in Osaka Bay and coastal waters of Western Japan indicate that the PFAAs in surface waters are influenced by sources from Keihanshin Metropolitan Area, mainly the Yodo River basin, and the dilution effect which naturally occurs during their transport to the Pacific Ocean. (C) 2016 Elsevier Ltd. All rights reserved. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/2955]

Environmental pollution is a global problem, while bioremediation technology removes pollutants from the environment using microorganisms. This study was aimed at investigating how a bioremediation process affected soil humification. In soil polluted with petroleum and its derivatives that was submitted to bioremediation, besides the total petroleum hydrocarbons and the number of microorganisms, quantitative and qualitative changes of isolated humic acids were determined during the process. The bioremediation of 150 m3 of polluted soil lasted 150 days. The level of total petroleum hydrocarbons decreased by 86.6 %, while the level of humic acids increased by 26.5 %. The elemental analysis showed the reduction of C and the H/C ratio and the increase of O and the O/C ratio of isolated humic acids during the process. The ratio of absorbencies at 465 and 665 nm also increased. Based on this and the Fourier-transform infrared spectra, it was shown that the humic acids isolated at the end of bioremediation were enriched with oxygen functional groups and aromatic structures. This study provides one of the first insights into the relationship between bioremediation and humification, as well as evidence of how hydrocarbon-degrading microorganisms have a significant influence on changes to humic acid structure during bioremediation. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III 43004]

The objective of this study was to investigate the growth kinetics of Bacillus subtilis NCIM 2063 under different cultivation conditions. For that purpose, the growth medium was supplemented with different glucose concentrations and exposed to different values of the oxygen transfer rate (OTR). As a result, it was found that the biomass yield, the specific growth rate and generation time were affected by the change of cultivation conditions and the composition of the nutrient medium. It was confirmed that glucose is readily available substrate that enhances the cultivation in the concentration range of 5-15 g/L. Also, it was proved that the restriction of available oxygen lowers the biomass yield and slows down the replication of bacteria. The maximum biomass concentration was achieved in the medium with 10 g/L of glucose and the OTR value of 10 mol/m³ h, when the specific growth rate and generation time were 0.273 h-1 and 2.54 h, respectively. Such biomass yield can be achieved in only 24 h, which is also economically acceptable. Therefore, the growth conditions optimized in this experiment are recommended as optimized values for further research, and can be used for economically sustainable and efficient cultivation of B. subtilis NCIM 2063.

7 1935 1921 42 M20 М21 Aquifer contamination by petroleum hydrocarbons leads to measurable changes of groundwater hydrochemistry, primarily due to the microbiological activity. This study analyzes this phenomenon at an historical kerosene-contaminated site in Vitanovac (central Serbia). Due to the long-term hydrocarbon contamination and exposure to aerobic and anaerobic biodegradation mechanisms, the lowest concentrations of O2, NO3−, and SO42− (electron acceptors) and the highest concentrations of Mn and Fe (products of microbial metabolic activity) overlap. The terminal redox-accepting processes in groundwater ranged from oxygen reduction to sulfate reduction. The most anoxic processes were registered in piezometers closest to the source of contamination, as was also confirmed by the redox potential (Eh) measurements. High electrical conductivity values and the highest TOC, SiO2, and Al concentrations also overlap in the contaminated zone close to the source of contamination. Scanning electron microscopy study of quartz grains from the zone undergoing the impact of biodegradation confirmed the occurrence of weathering microscale processes on mineral surfaces. Taking all these factors together, it seems reasonable to assume that microbiological activity has caused the enhanced weathering of silicate minerals.

An efficient encapsulation of the fullerene into two hydrophobized and one native polysaccharide provided water soluble supramolecular hybrids. After covalent modification of polysaccharides by cholesterol, noncovalent hybrids were prepared by a three-step procedure, including mixing of individual aqueous solutions of hydrophobized, as well as native sugar with solution of the fullerene in pyridine, dialysis and lyophilization. Although the degree of the fullerene incorporation into hydrophobized substrates, cholesterol-levan and cholesterol-pullulan, was lower in comparison to the native polysaccharide levan, hydrophobization provided nanoparticles with improved properties. The particle size distribution, studied by dynamic light scattering and scanning electron microscopy revealed formation of moderately polydisperse aggregates, with the diameter contraction in comparison to the corresponding free polysaccharide, especially in the case of hydrophobized substrates. The morphological examination, done by scanning electron microscopy indicated the self-organization of the fullerene-native polysaccharide to round individual structures, while fullerene-hydrophobized polysaccharide hybrids tend to form networks. The antioxidant activity of the synthesized polysaccharide-C60 noncovalent hybrids versus starting polysaccharides was investigated by the DPPH radical scavenging and the β-carotene-linoleic acid bleaching methods. In all three complexes, the radical scavenging ability of the fullerene remained preserved, and a positive effect of levan hydrophobization was observed. This is the peer-reviewed version of the manuscript: Kop, T.J., Jakovljević, D.M., Živković, L.S., Žekić, A., Beškoski, V.P., Milić, D.R., Gojgić-Cvijović, G.D., Bjelaković, M.S., Polysaccharide-fullerene supramolecular hybrids: synthesis, characterization and antioxidant activity, European Polymer Journal (2019), doi: [https://doi.org/10.1016/j.eurpolymj.2019.109461] The published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3803]

Reports about the influence of cerium-oxide nanoparticles (nCeO2) on plants are contradictory due to their positive and negative effects on plants. Surface modification may affect the interaction of nCeO2 with the environment, and hence its availability to plants. In this study, the uncoated and glucose-, levan-, and pullulan-coated nCeO2 were synthesized and characterized. The aim was to determine whether nontoxic carbohydrates alter the effect of nCeO2 on the seed germination, plant growth, and metabolism of wheat and pea. We applied 200 mgL-1 of nCeO2 on plants during germination (Ger treatment) or three week-growth (Gro treatment) in hydroponics. The plant response to nCeO2 was studied by measuring changes in Ce concentration, total antioxidative activity (TAA), total phenolic content (TPC), and phenolic profile. Our results generally revealed higher Ce concentration in plants after the treatment with coated nanoparticles compared to uncoated ones. Considering all obtained results, Ger treatment had a stronger impact on the later stages of plant development than Gro treatment. The Ger treatment had a stronger impact on TPC and plant elongation, whereas Gro treatment affected more TAA and phenolic profile. Among nanoparticles, levan-coated nCeO2 had the strongest and positive impact on tested plants. Wheat showed higher sensitivity to all treatments. Fil: Milenkovic, Ivana. Universidad de Belgrado; Serbia Fil: Mitrovic, Aleksandra. Universidad de Belgrado; Serbia Fil: Algarra, Manuel. Universidad de Madeira; Portugal Fil: Lazaro Martinez, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentina Fil: Rodríguez Castellón, Enrique. Universidad de Málaga. Facultad de Ciencias; España Fil: Maksimovic, Vuk. Universidad de Belgrado; Serbia Fil: Spasic, Sladana Z.. Universidad de Belgrado; Serbia Fil: Beskoski, Vladimir P.. Universidad de Belgrado; Serbia Fil: Radotic, Ksenija. Universidad de Belgrado; Serbia

The

Microbial polysaccharides, due to their unique physiochemical properties, have found application in the food industry, cosmetics, pharmacy and medicine. In the environment, microbes can use polysaccharides to alleviate the adverse effects of heavy metals in their close proximity. This adaptive property shows interesting potential for bioremediation. Herein, the effects of the exopolysaccharides (EPS) levan, produced by the bacterium Bacillus licheniformis NS032 and pullulan, produced by the fungus Aureobasidium pullulans CH-1 in the presence of copper (Cu2+) have been investigated for the first time on antioxidant enzyme activity, respiration and Cu2+ bioaccumulation of Daphnia magna as well as the bioluminescence of Vibrio fischeri. Both EPS decreased toxicity of Cu2+ in the acute test with D. magna. The activity of catalase (CAT) was significantly diminished after acute exposure to Cu2+ in comparison to treatments with Cu2+ and EPS, while in the prolonged acute exposure the CAT activity did not show statistically significant (P ≤ 0.05) differences between treatments with and without the EPS. According to ICP-MS results, during prolonged acute exposure of neonates, the bioaccumulation of Cu2+ in treatments without the EPS was 52.03 μg/g of biomass (wet), while in treatments with EPS, the bioaccumulation was lower by one order of magnitude. The respiration of neonates during acute exposure to Cu2+ with or without the EPS was monitored using the MicroOxymax respirometer, and the results show the EPS can positively effect the respiration. In the case of bacterial bioluminescence, the toxicity of Cu2+ decreased in treatments with EPS (30 min EC10) from 3.54 mg/L to 140.61 mg/L (levan) and 45.00 mg/L (pullulan). This study demonstrates protective effect of EPS against Cu2+ toxicity on D. magna and V. fischeri, and opens the door for further investigation of potential application of levan and pullulan in bioremediation of heavy metals and mitigation of their adverse effects in the aquatic environment. Supplementary data: [http://cherry.chem.bg.ac.rs/handle/123456789/3159]

Natural attenuation includes a number of processes that cause the reduction of groundwater contamination by petroleum hydrocarbons. Among these processes biodegradation often plays a major role, since microorganisms use petroleum hydrocarbons as the source of energy and carbon. Application of natural attenuation as a remediation approach requires detailed hydrogeological characterization of the contaminated site and monitoring of attenuation processes. This paper presents the results of monitored natural attenuation at the site of historical contamination by kerosene near Kraljevo. In order to demonstrate effects of biodegradation, following parameters in groundwater were measured: total petroleum hydrocarbons (TPH), electron acceptors (O2, NO3, SO4 2-), metabolic products of biodegradation (Mn, Fe), and redox potential (Eh). Obtained results and methodological approach can be considered useful in conceptualizing future studies of this type. Prirodno prečišćavanje objedinjuje niz procesa koji dovode do smanjenja zagađenja podzemnih voda naftnim ugljovodonicima. Biodegradacija često ima glavnu ulogu među ovim procesima, pošto mikroorgranizmi koriste naftne ugljovodonike kao izvor energije i ugljenika. Primena prirodnog prečišćavanja kao remedijacionog tretmana podrazumeva detaljnu hidrogeološku karakterizaciju zagađene lokacije i osmatranje procesa kojim dolazi do smanjenja zagađenja. U radu su prikazani rezultati osmatranja prirodnog prečišćavanja na lokaciji istorijskog zagađenja kerozinom kod Kraljeva. U cilju osmatranja efekata biodegradacije, u podzemnim vodama su vršena merenja sledećih parametara: ukupnih naftnih ugljovodonika (TPH), elektron akceptora (O2, NO3 -, SO4 2-), metaboličkih produkata biodegradacije (Mn, Fe) i redoks potencijala (Eh). Dobijeni rezultati i metodološki pristup mogu se smatrati korisnim kod koncipiranja budućih istraživanja ovog tipa.

One of the main global focuses of mankind today is the required switch to new energy sources. Generating energy from waste is one of the potential solutions that can be achieved using microbial fuel cells (MFCs). Microorganisms, thanks to their ability to degrade organic substrates in contaminated environments, could contribute to solving our pollution challenge. The aim of this study was to investigate the potential of sediment with its natural microbiota from the River Danube to optimize electricity generation using MFCs. 16S rRNA gene analysis identified the main bacterial genera in the river sediment, Clostridium, Bacillus and Tepidibacter, which were isolated and cultured in the laboratory. Addition of these cultured microorganisms to the MFC resulted in current density of 192 mA/m3, while the power density was about 8.80 mW/m3. Our study confirms proper selection and enrichment of the microbial community can optimize the amount of current obtainable from river sediment by MFCs. This is the peer-reviewed version of the article: Joksimović, K.; Žerađanin, A.; Randjelović, D.; Avdalović, J.; Miletić, S. B.; Gojgić-Cvijović, G. D.; Beškoski, V. Optimization of Microbial Fuel Cell Operation Using Danube River Sediment. Journal of Power Sources 2020, 476, 228739. [https://doi.org/10.1016/j.jpowsour.2020.228739] The published version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3617]

Grape pomace (GP) from Vitis labrusca, the main byproduct from “American table wine” production, is recalcitrant to degradation, and its accumulation is a serious problem with negative environmental impacts. In this work, transformation of grape pomace using a steam pretreatment followed by incubation of GP during a 90-day period with six different fungi were evaluated. Several fungi tested reduced the phytotoxicity of water-soluble fraction (WSFd) from steam-pretreated GP after 90 days’ incubation to lettuce and tomato seeds. U. botrytis caused the largest effective phytotoxicity reduction of WSFd (used in the concentration range of 10–1.25% p/v) and was the only fungus causing the removal of monoaromatic compounds. Therefore, this procedure with U. botrytis effectively reduces the availability of phytotoxic monoaromatic compounds in GP, which opens a way for the development of guidelines for the management of these wastes and their potential use as organic amendments in agricultural soil., Centro de Investigaciones en Fitopatología, Instituto de Botánica "Dr. Carlos Spegazzini", Facultad de Ciencias Agrarias y Forestales

Polycyclic aromatic hydrocarbons (PAHs) from petroleum and fossil fuels are one of the most dominant pollutants in the environment. Since aromatic fraction from petroleum diesel fuel is mainly composed of PAHs, it is important to discover new microorganisms that can biodegrade these compounds. This article describes the biodegradation of the aromatic fraction separated from petroleum diesel fuel using the strain Oerskovia sp. CHP-ZH25 isolated from petroleum oil-contaminated soil. The biodegradation was monitored by gravimetry and GC × GC-TOF MS. An innovative method was applied to visualize degraded compounds in the data provided by a GC × GC-TOF MS. It was shown that Oerskovia sp. CHP-ZH25 degraded 77.4% based on gravimetric analysis within 30 days. Average rate of degradation was 14.4 mg/L/day, 10.5 mg/l/day and 4.0 mg/l/day from 0 to 10 day, 10–20 and 20–30 day, respectively. The order of PAH degradation based on decrease in peak volume after 30 days of incubation was as follows: dibenzothiophene derivatives gt benzo[b]thiophene derivatives gt naphthalene derivatives gt acenaphthene derivatives gt acenaphthylene/biphenyl derivatives gt fluorene derivatives gt phenanthrene/anthracene derivatives. Here we demonstrated that Oerskovia sp. CHP-ZH25 could potentially be a suitable candidate for use in bioremediation of environments polluted with different PAHs. © 2018 Elsevier B.V. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/2950] This is the peer review version of the following article: Lješević, M.; Gojgić-Cvijović, G.; Ieda, T.; Hashimoto, S.; Nakano, T.; Bulatović, S.; Ilić, M.; Beškoski, V. Biodegradation of the Aromatic Fraction from Petroleum Diesel Fuel by Oerskovia Sp. Followed by Comprehensive GC×GC-TOF MS. Journal of Hazardous Materials 2019, 363, 227–232. [https://doi.org/10.1016/j.jhazmat.2018.10.005]

The Pseudomonas aeruginosa san ai strain was investigated for its capability to degrade the 2,6-di-tert-butylphenol (2,6-DTBP) plastic additive, a hazardous and toxic substance for aquatic life. This investigation was performed under different parameter values: 2,6-DTBP concentration, inoculum size, pH, and temperature. The GC-MS study showed that P. aeruginosa efficiently degraded 2,6-DTBP in the pH range of 5-8 at higher temperatures. Under exposure to 2,6-DTBP concentrations of 2, 10, and 100 mg L-1, the strain degraded by 100, 100, and 85%, respectively, for 7 days. Crude enzyme preparation from the biomass of P. aeruginosa san ai showed higher efficiency in 2,6-DTBP removal than that shown by whole microbial cells. Gene encoding for the enzymes involved in the degradation of aromatic compounds in P. aeruginosa san ai was identified. To complement the genomic data, a comparative proteomic study of P. aeruginosa san ai grown on 2,6-DTBP or sunflower oil was conducted by means of nanoLC-MS/MS. The presence of aromatic substances resulted in the upregulation of aromatic ring cleavage enzymes, whose activity was confirmed by enzymatic tests; therefore, it could be concluded that 2,6-DTBP might be degraded by ortho-ring cleavage. A comparative proteomics study of P. aeruginosa san ai indicated that the core molecular responses to aromatic substances can be summarized as the upregulation of proteins responsible for amino acid metabolism with emphasized glutamate metabolism and energy production with upregulated enzymes of glyoxylate bypass. P. aeruginosa san ai has a high capacity to efficiently degrade aromatic compounds, and therefore its whole cells or enzymes could be used in the treatment of contaminated areas. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3347]

Biodegradation often plays a major role among natural attenuation processes in the reduction of groundwater contamination by petroleum hydrocarbons. The study was conducted 25 years after the accidental spill of jet fuel at the site in Vitanovac in Serbia (1993-2018). During this period, natural attenuation processes were active without any anthropogenic stimulation. The traces of groundwater contamination were analyzed using GCxGC-MS chromatography. The microbiological analysis included measurements of total chemoorganoheterotrophs (TC), hydrocarbon degrading (HD), and anaerobic bacterial (AB) content in groundwater and sediments. The following hydrochemical indicators in groundwater were measured: O2, NO3−, Mn, Fe, SO42−, HCO3−. Due to the long-term hydrocarbon contamination and exposure to different biodegradation mechanisms, the lowest concentrations of electron acceptors and the highest concentrations of microbial metabolic activity products overlap. Based on the analysis of redox-sensitive compounds in groundwater samples, the terminal electron accepting processes ranged from mixed oxic-anoxic (O2-Fe(III)/SO4) to oxic (O2). The most anoxic conditions were registered in monitoring wells closest to the former source of contamination, as also confirmed by redox potential (Eh) in situ measurements. Overall, the study provides clear evidence of the activity and effects of biodegradation mechanisms under natural attenuation processes in groundwater contaminated by jet fuel. [https://gsa.confex.com/gsa/2019AM/webprogram/Paper332500.html]

The strain Pseudomonas aeruginosa san ai, isolated from an extreme environment (industrial mineral cutting oil, pH 10), is able to survive and persist in the presence of a variety of pollutants such as heavy metals and organic chemicals. The genome of P. aeruginosa san ai is 6.98 Mbp long with a GC content of 66.08% and 6485 protein encoding genes. A large number of genes associated with proteins, responsible for microbial resistance to heavy metal ions and involved in catabolism of toxic aromatic organic compounds were identified. P. aeruginosa san ai is a highly cadmium-resistant strain. Proteome analysis of biomass after cadmium exposal confirmed a high tolerance to sublethal concentrations of cadmium (100 mg/L), based on: extracellular biosorption, bioaccumulation, biofilm formation, controlled siderophore production and a pronounced metalloprotein synthesis. Proteins responsible for survival in osmostress conditions during exposure to elevated concentrations of cadmium (200 mg/L) demonstrate a strong genetic potential of P. aeruginosa san ai for survival and adaptation. Sequencing of P. aeruginosa san ai genome provides valuable insights into the evolution and adaptation of this microbe to environmental extremes at the whole-genome level, as well as how to optimally use the strain in bioremediation of chemically polluted sites. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3706]

The influence of four low-frequency magnetic field (MF) ranges 10–300 Hz, 10–100 Hz, 10–50 Hz and 50–100 Hz in scanning regime (all frequencies from selected range were scanned during 100 s repetitively during 24 h) on baker's yeast cells Saccharomyces cerevisiae was examined by continuous measurements of cumulative O2 consumption and cumulative CO2 production over 24 h with Micro-Oxymax® respirometer. Besides respiration activity, measurements of cell growth and glucose uptake were performed as well. Statistical analysis indicated that, among all investigated low-frequency MF ranges, range from 10 Hz to 50 Hz had the greatest influence to yeast cell respiration and cell growth. More precisely, for this region, paired two sample one-tail t-test showed statistically significant differences in cumulative O2 consumption, cumulative CO2 production and S. cerevisiae cell number. Moreover samples exposed to MF range from 10 Hz to 50 Hz showed the same behavior in all five replicates: lower cumulative O2 consumption, higher cumulative CO2 production and higher cell number compared to control sample. This could be important from the application aspect, in industry (food, feed, brewery etc.) and biotechnology, because changes in cells metabolism are not caused by chemical treatment. This is the peer-reviewed version of the article: Bubanja IN, Loncarevic B, Ljesevic M, Beskoski V, Gojgic-Cvijovic G, Velikic Z, Stanisavljev D, The influence of low- frequency magnetic field regions on the Saccharomyces cerevisiae respiration and growth, Chemical Engineering and Processing - Process Intensification (2019), [https://doi.org/10.1016/j.cep.2019.107593] Published version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3059]

Cerium oxide (CeO2) nanoparticles (CONPs) are interesting biomaterials with various applications in biomedicine, cosmetics and the pharmaceutical industry, but with limited practical application because of their low stability in aqueous media. The aim of this study was to obtain CONPs with increased stability by coating the particles. Microbial exopolysaccharides (levan, pullulan) and glucose were used to prepare CONPs under different synthesis conditions. Coating was attempted by adding the carbohydrates during (direct coating) or after (subsequent coating) the synthesis of CONPs. The obtained nanoparticles were characterized by X-Ray diffraction analysis, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The suspension stability of the uncoated and coated CONPs in aqueous media was evaluated by measuring the hydrodynamic size, zeta potential and turbidity. The FT-IR spectra revealed the differences between coated CONPs and showed the success of subsequent coating with carbohydrates. Coating with carbohydrates improved the stability the CONP suspension by decreasing the size of aggregated particles. The suspensions of levan- and glucose-coated CONPs had the best stability. In this study, CONPs were prepared using non-toxic materials, which were completely environmentally friendly. The obtained results open new horizons for CONP synthesis, improving their biological applications. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III45012 and Grant no. III43004]

We investigated the capability of microorganisms isolated from environments polluted with perfluoroalkyl adds (PFAAs) to conduct biotransformation of these emerging pollutants. Two different microbial consortia (chemoorganoheterotrophic bacteria and total yeast and molds) were isolated from two river sediments in Saitama and Osaka, Japan, known for long term pollution with perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). The microbial consortia were incubated in the presence of added PFOS and PFOA, and decreases in concentrations of these compounds were between 46-69% and 16-36%, respectively. Decreases in concentrations were, in part, due to sorption on biomass, but defluorinated PFOS and PFOA products were not detected. However, untargeted analysis suggested the presence of several metabolites found only in samples from consortia with PFOS and PFOA but not in the control samples. Molecular formula candidates were narrowed down to two options, C18H28O5F and C21H27O4. It was assumed that these formulas were associated with unsaturated monofluorinated fatty acids and hydrocarbons with multiple unsaturated bonds or ring structures. (C) 2018 Elsevier B.V. All rights reserved. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3114]

Pseudomonas aeruginosa san ai is a promising candidate for bioremediation of cadmium pollution, as it resists a high concentration of up to 7.2 mM of cadmium. Leaving biomass of P. aeruginosa san ai exposed to cadmium has a large biosorption potential, implying its capacity to extract heavy metal from contaminated medium. In the present study, we investigated tolerance and accumulation of cadmium on protein level by shotgun proteomics approach based on liquid chromatography and tandem mass spectrometry coupled with bioinformatics to identify proteins. Size exclusion chromatography was used for protein prefractionation to preserve native forms of metalloproteins and protein complexes. Using this approach a total of 60 proteins were observed as up-regulated in cadmium-amended culture. Almost a third of the total numbers of up-regulated were metalloproteins. Particularly interesting are denitrification proteins which are over expressed but not active, suggesting their protective role in conditions of heavy metal exposure. P. aeruginosa san ai developed a complex mechanism to adapt to cadmium, based on: extracellular biosorption, bioaccumulation, the formation of biofilm, controlled siderophore production, enhanced respiration and modified protein profile. An increased abundance of proteins involved in: cell energy metabolism, including denitrification proteins; amino acid metabolism; cell motility and posttranslational modifications, primarily based on thiol-disulfide exchange, were observed. Enhanced oxygen consumption of biomass in cadmium-amended culture versus control was found. Our results signify that P. aeruginosa san ai is naturally well equipped to overcome and survive high doses of cadmium and, as such, has a great potential for application in bioremediation of cadmium polluted sites. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3179]

The role of natural attenuation processes in groundwater contamination by petroleum hydrocarbons is of intense scientific and practical interest. This study provides insight into the biodegradation effects in groundwater at a site contaminated by kerosene (jet fuel) in 1993 (Vitanovac, Serbia). Total petroleum hydrocarbons (TPH), hydrochemical indicators (O-2 , NO3-, Mn, Fe, SO42-, HCO3- ), delta C-13 of dissolved inorganic carbon (DIC), and other parameters were measured to demonstrate biodegradation effects in groundwater at the contaminated site. Due to different biodegradation mechanisms, the zone of the lowest concentrations of electron acceptors and the zone of the highest concentrations of metabolic products of biodegradation overlap. Based on the analysis of redox-sensitive compounds in groundwater samples, redox processes ranged from strictly anoxic (methanogenesis) to oxic (oxygen reduction) within a short distance. The dependence of groundwater redox conditions on the distance from the source of contamination was observed. delta C-13 values of DIC ranged from -15.83 to -2.75 parts per thousand, and the most positive values correspond to the zone under anaerobic and methanogenic conditions. Overall, results obtained provide clear evidence on the effects of natural attenuation processes-the activity of biodegradation mechanisms in field conditions.

Various microorganisms isolated from polluted environments, such as Pseudomonas sp. and Micrococcus sp. can synthesize exopolysaccharides (EPSs) which are natural, non-toxic and biodegradable polymers. EPSs play a key role in protection of microbial cells under various external influences. For humans, these substances have potential use in many industries. EPSs can be applied as a flavor or a fragrance carrier, an emulsifier, a stabilizer, a prebiotic, an antioxidant or an antitumor agent. In this study, we characterized an environmental microorganism that produces EPS, optimized EPS production by this strain and characterized the EPS produced. Isolate CH-KOV3 was identified as Brachybacterium paraconglomeratum. The sucrose level in the growth medium greatly influenced EPS production, and the highest yield was when the microorganism was incubated in media with 500 g/L, of sucrose. The optimal temperature and pH were 28 degrees C and 7.0, respectively. The nuclear magnetic resonance (NMR) results and GC MS analysis confirmed that the residues were D-fructofuranosyl residues with beta-configuration, where fructose units are linked by beta-2,6-glycosidic bonds, with beta-2,1-linked branches. All these data indicate that the investigated EPS is a levan-type polysaccharide. Thus, it was concluded that Brachybacterium sp. CH-KOV3 could constitute a new source for production of the bioactive polysaccharide, levan. This is peer-reviewed version of the article: Aleksandra Djurić, Gordana Gojgić-Cvijović, Dragica Jakovljević, Branka Kekez, Jovana Stefanović Kojić, Maija-Liisa Mattinen, Inka Elina Harju, Miroslav M.Vrvić, Vladimir P.Beškoski, Brachybacterium sp.CH-KOV3 isolated from an oil-polluted environment–a new producer of levan, International Journal of Biological Macromolecules, 2017, 104, 311-321, [http://dx.doi.org/10.1016/j.ijbiomac.2017.06.034] [http://cer.ihtm.bg.ac.rs/handle/123456789/2097]

This paper describes experiments with standard humic acids (HA-S) and humic acids (HA) isolated from soil that was contaminated with mazut and treated with a consortium of microorganisms for the process of bioremediation (HA-E). Both acids inhibited the toxicity of ferric chloride and increased the growth of a zymogenous microbial consortia compared with controls. Electron paramagnetic resonance spectroscopy showed that HA-S and HA-E exhibit high anti-oxidative activity involving free radical scavenging and iron sequestration. HA additionally promote microbial consortium growth by providing protection from oxidative stress.

This letter and comments within refer to the article (hereinafter: ?Paper?) published in the Journal of the Serbian Chemical Society, 2014, Volume 79, Issue 6, Pages: 729-741: Srdjan Stankovic, Ivana Moric, Aleksandar Pavic, Branka Vasiljevic, D. Barrie Johnson and Vladica Cvetkovic, Investigation of the microbial diversity of an extremely acidic, metal-rich water body (Lake Robule, Bor, Serbia).

Bioremediation is the process of detoxification or elimination of pollutants using microorganisms with different metabolic capabilities. Biodegradation by natural populations of microorganisms is one of the primary mechanisms by which oil and other pollutants of hydrocarbon origin can be removed from the environment and it is also much cheaper than the other remediation technologies.In this study, we analyzed the samples of historical waste from the oil industry, which contained sand, organic materials, heavy fuel oil and catalysts used during the process of hydrodesulfurization (HDS) of oil. The aim was to examine the fate of cobalt and molybdenum, toxic heavy metals present in those catalysts. A consortium of microorganisms isolated from the complex pollutants from the oil industry was added to the samples. During the study, beside the transformation of cobalt and molybdenum forms, we also monitored the biodegradation process of the total petroleum hydrocarbons (TPH).

The objective of this study was to stimulate microbial biodegradation of petroleum pollution in groundwater and to analyze changes in the abundance and distribution of organic compounds detectable in petroleum. Bioremediation was conducted in a closed bipolar system, by bioaugmentation with consortia of hydrocarbon degrading microorganisms (HD) and biostimulation with nutrients. Comprehensive twodimensional gas chromatography-mass spectrometry (GC X GC-MS) was used to visualize all fractions simultaneously. During the study, the content of total petroleum hydrocarbon (TPH) in groundwater decreased by 92.7% of the initial level, and the average rate of biodegradation was 0.1 mg/L per day. Increased numbers of HD were observed and the dominant genera were Pseudomonas, Rhodococcus, Achromobacter, Bacillus, and Micromonospora. In the first 30 days of bioremediation, there was no significant biodegradation of n-alkanes and petroleum biomarkers - isoprenoids such as pristane and phytane, and polycyclic-saturated hydrocarbons such as terpanes and steranes. However, after 60 days of bioremediation, more than 95% of n-alkanes, terpanes and steranes were biodegraded. Phenanthrene and its methyl-,dimethyl-, and trimethyl-isomers were biodegraded and reduced by more than 99% of their initial levels. However, their decomposition had clearly commenced after just 30 days. This is a somewhat surprising result since it follows that the phenanthrenes were more susceptible to biodegradation than the n-alkanes and isoprenoids. Depending on the microbial community used for bioaugmentation, biodegradation of phenanthrene can precede biodegradation of saturated hydrocarbons. This is the peer-reviewed version of the following article: Beškoski, V. P.; Miletić, S.; Ilić, M.; Gojgić-Cvijović, G.; Papić, P.; Marić, N.; Šolević-Knudsen, T.; Jovančićević, B. S.; Nakano, T.; Vrvić, M. M. Biodegradation of Isoprenoids, Steranes, Terpanes, and Phenanthrenes During In Situ Bioremediation of Petroleum-Contaminated Groundwater. Clean - Soil, Air, Water 2017, 45 (2). [https://doi.org/10.1002/clen.201600023] [http://cer.ihtm.bg.ac.rs/handle/123456789/2183]

Phenanthrene and methyl-phenanthrenes are major aromatic pollutants originating in particular from fuel oil. Phenanthrene is usually degraded faster than methyl-phenanthrenes under geological and environmental conditions. Here, we report a preferential and accelerated biodegradation of methyl-phenanthrenes versus phenanthrene in soil contaminated by fuel oil. The polluted soil was mixed with sawdust and sand to form a homogenized biopile. The biopile was continuously sprayed with microbial consortia isolated from crude oil-contaminated soil and treated by biosurfactants and nutritive substances for biostimulation. During a 6-month bioremediation experiment, a steady increase in the relative abundance of phenanthrene compared to methyl-phenathrenes was observed by gas chromatography-mass spectrometry. The increase was the highest for trimethyl-phenanthrenes, with a phenanthrene/trimethyl-phenanthrenes ratio increasing from 0.42 to 2.45. By contrast, the control, non-stimulated samples showed a ratio decrease from 0.85 to 0.11. Moreover, the results showed that the level of degradability depends on the number of methyl groups.

The contamination of soil and water with petroleum and its products occurs due to accidental spills during exploitation, transport, processing, storing and use. In order to control the environmental risks caused by petroleum products a variety of techniques based on physical, chemical and biological methods have been used. Biological methods are considered to have a comparative advantage as cost effective and environmentally friendly technologies. Bioremediation, defined as the use of biological systems to destroy and reduce the concentrations of hazardous waste from contaminated sites, is an evolving technology for the removal and degradation of petroleum hydrocarbons as well as industrial solvents, phenols and pesticides. Microorganisms are the main bioremediation agents due to their diverse metabolic capacities. In order to enhance the rate of pollutant degradation the technology optimizes the conditions for the growth of microorganisms present in soil by aeration, nutrient addition and, if necessary, by adding separately prepared microorganisms cultures. The other factors that influence the efficiency of process are temperature, humidity, presence of surfactants, soil pH, mineral composition, content of organic substance of soil as well as type and concentration of contaminant. This paper presents a review of our ex situ bioremediation procedures successfully implemented on the industrial level. This technology was used for treatment of soils contaminated by crude oil and its derivatives originated from refinery as well as soils polluted with oil fuel and transformer oil.

This paper presents the results of an ex situ bioremediation of soil contaminated by mazut (heavy residual fuel oil) in the field scale (600 m(3)). The treatment-bed (thickness 0.4 m) consisted of mechanically mixed mazut-contaminated soil, softwood sawdust as an additional carbon source and crude river sand, as a bulking and porosity increasing material. The inoculation/reinoculation was conducted periodically using a biomass of a consortium of zymogenous microorganisms isolated from a bioremediation substrate. The biostimulation was performed through addition of nutritious substances (N, P and K). The aeration was improved by systematic mixing of the bioremediation system. After 50 days, the number of hydrocarbon degraders had increased a 100 fold. Based on the changes in the group composition, the average biodegradation rate during bioremediation was 24 mg kg(-1) day(-1) for the aliphatic fraction, 6 mg kg(-1) day(-1) for the aromatic fraction and 3 mg kg(-1) day(-1) for the nitrogen-sulphur-oxygen compounds (NSO)-asphaltene fraction. In the saturated hydrocarbon fraction, gas chromatography-mass spectrometry (GC-MS) in the single ion-monitoring mode (SIM) was applied to analyse isoprenoids pristane and phytane and polycyclic molecules of sterane and triterpane type. Biodegradation occurred during the bioremediation process, as well as a reduction of the relative quantities of isoprenoids, steranes, tri- and tetracyclic terpanes and pentacyclic terpanes of the hopane type. Prikazani su rezultati ex situ bioremedijacije zemljišta kontaminiranog mazutom na industrijskom nivou (600 m3). Bioremedijacioni materijal (debljine 0,4 m) se sastojao od mehanički pomešanih mazutom zagađenog zemljišta, čamove piljevine kao dodatnog izvora ugljenika i neprečišćenog rečnog peska, dodatog u cilju mešanja i povećanja poroznosti. Inokulacija/reinokulacija (bioaugmentacija) je periodično rađena sa biomasom konzorcijuma zimogenih mikrooorganizama izolovanih iz supstrata za bioremedijaciju. Biostimulacija je realizovana dodatkom hranljivih supstanci (N, P i K). Aeracija je poboljšavana sistematskim mešanjem bioremedijacionog sistema. Nakon 50 dana broj mikroorganizama koji degradiraju ugljovodonike povećan je 100 puta. Na osnovu promena u grupnom sastavu prosečna stopa biodegradacije tokom bioremedijacije je bila za alifatičnu frakciju 24 mg kg-1 po danu, za aromatičnu 6 mg kg-1 po danu i 3 mg kg-1 po danu za NSO-asfaltensku frakciju. U zasićenoj ugljovodoničnoj frakciji metodom GC-MS (SIM metod) analizirani su izoprenoidi pristan i fitan i policiklični molekuli steranskog i triterpanskog tipa. Tokom bioremedijacionog procesa došlo je do biodegradacije i smanjenja relativnih količina izoprenoida, sterana, tri- i tetracikličnih terpana i pentacikličnih terpana hopanskog tipa.

The biogeochemical activity of microorganisms from sulphide biogeocoenosis in the zones of sulphide copper ores deposits in East Serbia has been Studied by us since 1975. All deposits of copper mineralization were dominantly sulphides and arsenic sulphides with the constant presence of pyrite. The obtained results proved that the biochemical and chemical activity of thionic bacteria have an influence on the global pollution of waters. All the waters were characterized by a low pH value and by high Eh values, mineralization (over 7 gL(-1)) and in total iron (even more than 4 gL(-1)) dominantly as Fe3+ ions. These waters were characterized by toxic concentrations of copper ions, within the limits from about 2 to almost 200 mgL(-1) and arsenic, up to more than 4 mgL(-1). These waters partly arrive in an aquifer and the major part flows into surface water courses gravitating towards the Danube River, which empties into the Black Sea. In a hypothetical case, if maximum concentrations of copper and arsenic and maximum capacity of the springs are considered, under the assumption that the pollutants do not precipitate on the way to the main recipient, the striking information is obtained that the Danube River receives about 31 t of copper and more than 0.6 t of arsenic per annum from one place alone, which undoubtedly points to the contribution of thionic bacteria as "biological agents" to global pollution of surface and ground waters. BIOHYDROMETALLURGY: A MEETING POINT BETWEEN MICROBIAL ECOLOGY, METAL RECOVERY PROCESSES AND ENVIRONM

Bioremediation, a process that utilizes the capability of microorganism to degrade toxic waste, is emerging as a promising technology for the treatment of soil and groundwater contamination. The technology is very effective in dealing with petroleum hydrocarbon contamination. The aim of this study was to examine the composition of the microbial consortium during the ex situ experiment of bioremediation of soil heavily contaminated with crude oil and its products from the Oil Refinery Pancevo, Serbia. After a 5.5-month experiment with biostimulation and bioventilation, the concentration of the total petroleum hydrocarbons (TPH) had been reduced from 29.80 to 3.29 g/kg (89 %). In soil, the dominant microorganism population comprised Gram-positive bacteria from actinomycete-Nocardia group. The microorganisms which decompose hydrocarbons were the dominant microbial population at the end of the process, with a share of more than 80 % (range 107 CFU/g). On the basis of the results, it was concluded that a stable microbial community had been formed after initial fluctuations.

Oil shale is one of the alternative sources of hydrocarbon fuels ("synthetic petroleum") but is characterized by increased sulfur and nitrogen contents, which represent even greater ecological problems in its use compared to classical fuels. Acidithiobacillus ferrooxidans (At. f.) is capable of oxidizing pyrite to iron(III)-ions, providing a strong oxidation agent at low pH. We have used this oxidizing agent for the oxidation of the sulfur present in dibenzothiophene (DBT), as a substrate model to demonstrate its potential to oxidize organically bound sulfur in oil shale. An HCl-concentrate of oil shale was used as the hydrocarbon matrix. Acidithiobacillus ferrooxidans has already been shown to oxidize the pyritic sulfur component, thereby potentially providing a complete sulfur removal system. By applying GC-MS, we established that DBT transformation occurred by oxidation or elimination of sulfur. The products obtained were more soluble in water than the parent compounds, which reduced the concentration of organic sulfur. (C) 2008 Elsevier B.V. All rights reserved.

Iron and sulfur oxidizing chemolithoautotrophic acidophilic bacteria, such as Acidithiobacillus species, hold the dominant role in mine environments characterized by low pH values and high concentrations of reduced sulfur and iron compounds, such as ores, rocks and acid drainage waters from mines. On the other hand, heterotrophic microorganisms, especially their biofilms, from these specific niches are receiving increased attention, but their potential eco-physiological roles have not been fully understood. Biofilms are considered a threat to human health, but biofilms also have beneficial properties as they are deployed in waste recycling and bioremediation systems. We have analyzed interactions of the metal tolerant heterotrophic microorganisms in biofilms with iron oxidizing autotrophic bacteria both from the sulphidic mine environment (copper mine Bor, Serbia). High tolerance to Cu2+, Cd2+ and Cr6+ and the presence of genetic determinants for the respective metal tolerance and biofilm-forming ability was shown for indigenous heterotrophic bacteria that included strains of Staphylococcus and Rhodococcus. Two well characterized bacteria-Pseudomonas aeruginosa PAO1 (known biofilm former) and Cupriavidus metallidurans CH34 (known metal resistant representative) were also included in the study. The interaction and survivability of autotrophic iron oxidizing Acidithiobacillus bacteria and biofilms of heterotrophic bacteria during co-cultivation was revealed. Finally, the effect of heterotrophic biofilms on bioleaching process with indigenous iron oxidizing Acidithiobacillus species was shown not to be inhibitory under in vitro conditions. (C) 2016 Elsevier Ltd. All rights reserved. Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3546]