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Engine oil is a significant environmental contaminant, and its removal is challenging due to its persistent nature in the ecosystem. Engine oil is a significant environmental contaminant, and its removal is challenging due to its persistent nature in the ecosystem. Biodegradation of used engine oil using indigenous bacteria from contaminated soil is a cost-effective approach for environmental cleanup. This study investigated the efficiency of a single bacterial isolate and a formulated bacterial consortium (BC), both sourced from the contaminated soil of a mechanical workshop, in the biodegradation of engine oil. The bacterial strains were identified by 16 S rDNA sequencing as Ochrobactrum intermedium LMG 3301 and Bacillus paramycoides MCCC1A04098/BC. Additionally, the study sought to evaluate the growth and physiological activity of the oil-degrading bacteria in the stirred batch bioreactor (SBR) both individually and in consortia. The biodegradation of 0.675% of used engine oil, bacterial growth, and enzymatic activity was achieved under elevated aerobic conditions and optimal environmental factors for 0–5 days. The BC was more efficient at biodegrading used engine oil with 10% (85%) TPH increased removal compared to O. intermedium (77%) in a stirred batch bioreactor at pH 7.5, temperature 37 °C, and inoculum size 15 ml of OD600nm = 1. The results showed that consortium and single bacteria could both degrade longer-chain alkanes, but their abilities to handle shorter-chain alkanes varied. While a consortium generates more lipase enzymes, a single bacterium produces more dehydrogenase, which is connected to energy generation in the form of NADPH. As a result, O. intermediate bacterium expends a large deal of effort to break down the oil on its own. The single’s faster growth rate and shorter doubling time compared to the consortium indicate the efficacy and growth abilities of O. intermedium when given a UEO substrate. However, the consortium’s slower growth rate and longer doubling time were likely brought on by either the slower-growing partner or the length of time it takes for a syntrophic relationship to develop. The study demonstrated the bioeffectiveness of using a sequencing batch bioreactor for heavy UEO elimination and offered two distinct bacteria formulations for successful bioremediation of hazardous pollutants.

Background Bacteria have developed different mechanisms for the transformation of metalloid oxyanions to non-toxic chemical forms. A number of bacterial isolates so far obtained in axenic culture has shown the ability to bioreduce selenite and tellurite to the elemental state in different conditions along with the formation of nanoparticles—both inside and outside the cells—characterized by a variety of morphological features. This reductive process can be considered of major importance for two reasons: firstly, toxic and soluble (i.e. bioavailable) compounds such as selenite and tellurite are converted to a less toxic chemical forms (i.e. zero valent state); secondly, chalcogen nanoparticles have attracted great interest due to their photoelectric and semiconducting properties. In addition, their exploitation as antimicrobial agents is currently becoming an area of intensive research in medical sciences. Results In the present study, the bacterial strain Ochrobactrum sp. MPV1, isolated from a dump of roasted arsenopyrites as residues of a formerly sulfuric acid production near Scarlino (Tuscany, Italy) was analyzed for its capability of efficaciously bioreducing the chalcogen oxyanions selenite (SeO 3 2− ) and tellurite (TeO 3 2− ) to their respective elemental forms (Se 0 and Te 0 ) in aerobic conditions, with generation of Se- and Te-nanoparticles (Se- and TeNPs). The isolate could bioconvert 2 mM SeO 3 2− and 0.5 mM TeO 3 2− to the corresponding Se 0 and Te 0 in 48 and 120 h, respectively. The intracellular accumulation of nanomaterials was demonstrated through electron microscopy. Moreover, several analyses were performed to shed light on the mechanisms involved in SeO 3 2− and TeO 3 2− bioreduction to their elemental states. Results obtained suggested that these oxyanions are bioconverted through two different mechanisms in Ochrobactrum sp. MPV1. Glutathione (GSH) seemed to play a key role in SeO 3 2− bioreduction, while TeO 3 2− bioconversion could be ascribed to the catalytic activity of intracellular NADH-dependent oxidoreductases. The organic coating surrounding biogenic Se- and TeNPs was also characterized through Fourier-transform infrared spectroscopy. This analysis revealed interesting differences among the NPs produced by Ochrobactrum sp. MPV1 and suggested a possible different role of phospholipids and proteins in both biosynthesis and stabilization of such chalcogen-NPs. Conclusions In conclusion, Ochrobactrum sp. MPV1 has demonstrated to be an ideal candidate for the bioconversion of toxic oxyanions such as selenite and tellurite to their respective elemental forms, producing intracellular Se- and TeNPs possibly exploitable in biomedical and industrial applications.

Bacterial systems have drawn an increasing amount of attention on lignin valorization due to their rapid growth and powerful environmental adaptability. In this study, Klebsiella pneumoniae NX-1, Pseudomonas putida NX-1, and Ochrobactrum tritici NX-1 with ligninolytic potential were isolated from leaf mold samples. Their ligninolytic capabilities were determined by measuring (1) the cell growth on kraft lignin as the sole carbon source, (2) the decolorization of kraft lignin and lignin-mimicking dyes, (3) the micro-morphology changes and transformations of chemical groups in kraft lignin, and (4) the ligninolytic enzyme activities of these three isolates. To the best of our knowledge, this is the first report that Ochrobactrum tritici species can depolymerize and metabolize lignin. Moreover, laccase, lignin peroxidase, and Mn-peroxidase showed high activities in P. putida NX-1. Due to their excellent ligninolytic capabilities, these three bacteria are important supplements to ligninolytic bacteria library and could be valuable in lignin valorization.

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

The petroleum hydrocarbons in seawater have been worldwide concern contaminants. Biological method, with the advantages of low cost, minimal environmental impact, and no secondary pollution, is a promising method for petroleum hydrocarbon treatment. In this study, two strains, identified as Stenotrophomonas acidaminiphila and Ochrobactrum , were demonstrated to possess the ability to degrade petroleum hydrocarbons. The mixed culture composed of Stenotrophomonas acidaminiphila and Ochrobactrum at a 2:1 ratio was able to achieve 79.41% degradation of the total petroleum hydrocarbons after 5 days. Besides, the average removal efficiencies of C10-C30 components in petroleum hydrocarbons by Stenotrophomonas acidaminiphila , Ochrobactrum , and mixed culture were 62.98%, 59.14% and 73.30%, respectively. The possible degradation pathways of petroleum hydrocarbons had been speculated through gas chromatography-mass spectrometry (GC-MS) and differential gene expression metabolomics analyses. The toxicity of products from the biodegradation of petroleum hydrocarbons was greatly reduced.

Background Alkaline thermostable lipase and biosurfactant producing bacteria are very interested at detergent applications, not only because of their eco-friendly characterize, but alsoproduction lipase and biosurfactant by using cheap materials. Ochrobactrum intermedium strain MZV101 was isolated as washing powder resistant, alkaline thermostable lipase and biosurfactant producing bacterium in order to use at detergent applications. Methods O. intermedium strain MZV101 produces was lipase and biosurfactant in the same media with pH 10 and temperature of 60 °C. Washing test and some detergent compatibility character of lipase enzyme and biosurfactant were assayed. The antimicrobial activity evaluated against various bacteria and fungi. Results Lipase and biosurfactant produced by O. intermedium strain MZV101 exhibited high stability at pH 10–13 and temperature of 70–90 °C, biosurfactant exhibits good stability at pH 9–13 and thermostability in all range. Both lipase and biosurfactant were found to be stable in the presence of different metal ions, detergents and organic solvents. The lipase enzyme extracted using isopropanol with yield of 69.2% and biosurfactant with ethanol emulsification index value of 70.99% and yield of 9.32 (g/l). The single band protein after through from G-50 Sephadex column on SDS-PAGE was calculated to be 99.42 kDa. Biosurfactant O. intermedium strain MZV101 exhibited good antimicrobial activity against Gram-negative bacteria and against various bacterial pathogens. Based upon washing test biosurfactant and lipase O. intermedium strain MZV101considered being strong oil removal. Conclusion The results of this study indicate that isolated lipase and biosurfactant with strong oil removal, antimicrobial activity and good stability could be useful for detergent applications. Graphical abstract

Brucellosis is a zoonosis with non-specific clinical symptoms involving multiple systems and organs. Its prevalence is low in most of EU countries, which can lead to the difficulties in laboratory and clinical diagnostic. Due to its relationship to the Ochrobactrum spp., it may be misclassified in rapid identification systems. We present a case of a 13-year-old immunocompetent girl who was examined several times for fever, fatigue, night sweats and weight loss; laboratory results showed mildly elevated C-reactive protein, anaemia and leukopenia. Four weeks before the onset of symptoms, she had been on a family holiday in Egypt. Given her symptoms, a haemato-oncological or autoimmune disease was considered more likely. The diagnosis of Brucella spondylitis was made after 4 months. The main reasons for this delay were as follows: low specificity of clinical symptoms, delay in completing the travel history, inconclusive initial serological results and misidentification of the blood culture isolate as Ochrobactrum sp. Even in countries with a low incidence of brucellosis, it is essential to educate healthcare professionals about the disease. Low specificity of symptoms and limited experience of laboratory staff may lead to late diagnosis with risk of complications and poor outcome. If Ochrobactrum spp. is detected in clinical specimens by rapid identification, careful re-evaluation must follow and all measures to prevent laboratory-acquired infections must be taken until Brucella spp. is unequivocally excluded.

Bacteria in natural associations with agricultural crops are promising for use in the improvement of clonal micropropagation of plants. We clarified the taxonomic position of Ochrobactrum cytisi strain IPA7.2 and investigated its tolerance for salinity, high temperature, and glyphosate pollution. We also tested the strain’s potential to promote the growth of potato (Solanum tuberosum L.) microplants. Using the IPA7.2 draft genome (no. NZ_MOEC00000000), we searched for housekeeping genes and also for the target genes encoding glyphosate tolerance and plant-growth-promoting ability. A multilocus sequence analysis of the gap, rpoB, dnaK, trpE, aroC, and recA housekeeping genes led us to identify isolate IPA7.2 as O. cytisi. The strain tolerated temperatures up to 50 °C and NaCl concentrations up to 3–4%, and it produced 8 µg ml−1 of indole-3-acetic acid. It also tolerated 6 mM glyphosate owing to the presence of type II 5-enolpyruvylshikimate-3-phosphate synthase. Finally, it was able to colonize the roots and tissues of potato microplants, an ability preserved by several generations after subculturing. We identified the development phase of potato microplants that was optimal for inoculation with O. cytisi IPA7.2. Inoculation of in vitro-grown 15-day-old microplants increased the mitotic index of root meristem cells (by 50%), the length of shoots (by 34%), the number of leaves (by 7%), and the number of roots (by 16%). Under ex vitro conditions, the inoculated plants had a greater leaf area (by 77%) and greater shoot and root dry weight (by 84 and 61%, respectively) than did the control plants. We recommend O. cytisi IPA 7.2 for use in the growing of potato microplants to improve the production of elite seed material.Graphical abstract

Mushroom tumor on Flammulina velutipes has become the main disease during the off-season cultivation of F. velutipes while the causal organism has remained unknown. The present study was aimed at identifying the pathogen confirming its pathogenisity following Koch's Postulates, characterizing it using morphological, physiological, biochemical and molecular features, and studying its current distribution. We determined that mushroom tumor is a new bacterial infection disease caused by Ochrobactrum pseudogrignonense. It produces tumor-like structures on the surface of the substrate, and inhibits the formation of primordia and fruiting of F. velutipes. The molecular studies showed that this new pathogen is closely related to Ochrobactrum based on 16S rRNA sequences. This is the first time that Ochrobactrum has been shown to be a pathogen of a mushroom. Mushroom tumor is a new bacterial infection disease on Flammulina velutipes caused by Ochrobactrum pseudogrignonense.

Biodegradation is one of the important methods for the treatment of industrial wastewater containing aniline. In this paper, a degrading bacterium named MC-01, which could survive in high concentration aniline wastewater, was screened from industrial wastewater containing aniline and sludge. MC-01 was preliminarily identified as Ochrobactrum sp . based on the amplified 16S rDNA gene sequence and Biolog system identification. MC-01 was highly resistant to aniline. After 24-h culture under aniline concentration of 6500 mg/L, the amount of bacterium survived still remained 0.05 × 10 6  CFU/mL. Experiments showed that there was no coupling expression between the growth of MC-01 and aniline degradation. The optimum growth conditions in LB culture were pH 6.0, 30 °C of temperature, and 4% of incubation amount, respectively. And the optimum conditions of aniline degradation of MC-01 were pH 7.0, 45 °C of temperature, and 3.0% of salt concentration, respectively. The degradation rate of MC-01 (48 h) in different aniline concentrations (200~1600 mg/L) was stable under the optimum conditions, which could reach more than 75%.