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Eleven isolates of sulphate-reducing bacteria (SRB) were isolated from soil contaminated with crude oil derivatives and petroleum-refining wastewaters and used to investigate the effectiveness of carbon reduction and biotransformation of phosphogypsum. One of the isolates (culture no. 10) was found to be very effective with 90% carbon reduction (measured as COD) and the simultaneous biotransformation of approximately 2.65g phosphogypsum/L in industrial petroleum-refining wastewaters.
Background. Selenium is an element of very great importance for the proper functioning of the human body, mainly due to its antioxidant properties. Selenium exhibits a preventive effect in the case of cardiovascular disease, the immune system, male infertility and inhibits the toxic action of other agents. Selenium is important for Hashimoto’s disease. Intake of selenium in the diet slows the aging process. The biological and toxicological effects of selenium strongly depend on its chemical form. Some organisms for example: plant, yeast, are capable of metabolizing low bioavailable selenium compounds (inorganic selenium) into its high bioavailable forms (organic selenium). Objective. The aim of this study was to investigate the bio-transformation of selenium by Lactobacillus bacteria towards the characterisation of selenium metabolites. Material and Methods. The speciation of selenium was evaluated by high performance liquid chromatography with inductively coupled plasma mass spectrometry detector. The extraction of selenium species from lyophilized bacteria was executed with water, the mixture of lipase and protease, as well as lisozyme and sodium dodecyl sulphate. Results. All investigated bacteria strains cultivated in the presence of Na2SeO3 effectively uptake selenium. Surprisingly, none of the applied extraction media exhibited a strong power to release the majority of the uptaken selenium compounds. Thus a maximum of 10% of the selenium was extracted from bacteria exposed to the enzymes. However, it was found that Lactobacillus bacteria are able to metabolize inorganic ions of selenium (IV) into Se-methionine, Se-methyloselenocysteine and other unidentified forms. Conclusions. The study confirmed the ability of probiotic bacteria to biotransform inorganic selenium into its organic derivatives. Therefore, Se-enriched bacteria can be considered as an addition to the functional food.
P. ixocarpa hairy root cultures were obtained after the transformation with A. rhizogenes strain ATCC 15834. The ability of P. ixocarpa hairy roots to biotransform HQ to arbutin was examined. The roots were treated 3 times with the same HQ concentration on 3 consecutive days or every 3 days. Despite these differences the highest arbutin yield and the highest biotransformation ratio were similar in both variants, 13.1 and 14.4 mg·25 cm⁻³ of the cultures and 67.6% and 70.6%, respectively. However, in the case of shorter intervals between treatments the highest levels of these parameters were achieved earlier. Multiple treatment of lower HQ concentration reduced its harmful effects on root biomass growth.
Microbial transformation of 3-methoxyflavone into 3’-hydroxyflavon-3-yloxymethyl myristate was presented. Six filamentous fungi were used as biocatalysts: a wild strain of Aspergillus niger KB, its four UV mutants (A. niger MB, SBP, SBJ, 13/5) and the strain of Penicillium chermesinum 113. The highest yields were observed for the strains of A. niger KB and A. niger SBP (69.8% and 63.1%, respectively).
Three strains of microorganisms: Bacillus subtilis, Serratia liquefaciens and Escherichia coli were tested as whole-cell biocatalysts for the kinetic resolution of isomers of two new phosphonoacetic acid derivatives. Used compounds possess two chiral centres – one at the carbon adjacent to both functional groups and the other at the phosphorus. Biocatalytic hydrolysis of 2-butyryloxy-2-(butoxyetoxyphosphinyl)acetic acid and 2-butyryloxy-2-(isobutoxyetoxyphosphinyl) acetic acid with whole cells of Bacillus subtilis produced corresponding hydroxyphosphonates with diastereoselectivity ranging from 50 to 60%.
The paper presents the activity of anaerobic bacterial communities isolated from soil polluted by aircraft fuel on distillery decoctions with phosphogypsum. The microorganisms were selected using the microcosms method, and then enriched on Postgate medium with ethanol. The isolated communities became the inoculum to establish a culture on potato and rye distillery decoctions. The obtained results show that a simultaneous removal of two industrial wastes such as phosphogypsum and distillery decoctions is possible. The introduction of a inoculation comprising a selected anaerobic bacterial community into the culture does not influence the increase of the biotransformation process efficiency.
The biotransformation of phosphogypsum in cultures of sulfate-reducing bacteria (SRB) isolated from crude petroleum-refining wastewaters or purified using activated sludge method was studied. Selection was with the microcosms method on Postgate and minimal medium with different carbon sources, Emerson medium and petroleum-refining wastewaters. Highest hydrogen sulfide production, in excess of 500 mg/L, was observed in culture of microorganisms isolated from purified petroleum-refining wastewaters in Postgate medium with phenol as sole carbon source. 76% phenol reduction with simultaneous biotransformation of 2.7g phosphogypsum/L (1350 mg SO₄/L) was obtained. The results regarding post-culture sediment indicated 66% utilization of phosphogypsum introduced into the culture (5 g/L), which reflects the active biotransformation of phosphogypsum by the community selected from the wastewaters.
The effect of zinc on the biotransformation of phosphogypsum, COD reduction and growth rate (μmax day-1) of an SRB community and Desulfotomaculum ruminis in media with sodium lactate or ethanol was examined. Depending on the form of zinc (Zn3(PO4)2 x 4H2O, ZnSO4 x7H2O, ZnCl2, Zn(NO3)2 x 6H2O) and its initial concentration (0-80 mg Zn2+/l) lower sulphate reduction and COD reduction was observed. The effect of Zn2+ also depended on the composition of the studied populations and carbon source in the medium. The lowest inhibition of specific growth rate was determined in cultures of the pure strain and in medium with zinc phosphate (with lactate or ethanol IC50=63 or 75 mg Zn2+/l, respectively) and the highest in cultures of sulphate-reducing bacterial communities in medium with zinc nitrate (with lactate or ethanol IC50= 35 or 20 mg Zn2+/l, respectively).
Optimization of conditions for hydroquinone biotransformation into its β-ᴅ-glucoside, arbutin, in agitated shoot cultures of Ruta graveolens L. and Hypericum perforatum L. allowed us to obtain a maximum content of this important therapeutic and cosmetic product of 7.8 and 7.2% (dry weight), respectively. These contents are higher than respective values required for standardization of known arbutin-containing plant raw materials according to the European Pharmacopoeia and national pharmacopoeias of European countries.
The biotransformation of (–)–menthol by Mucor ramannianus was studied. It was carried out with sporulated surface cultures of Mucor ramannianus. The main bioconversion products obtained from (–)–menthol were trans-p-menthan-8-ol, trans-menth-2-en-1-ol, sabinane, pmenthane- 3,8-diol, isomenthol, and 1,8-cineole, also resulting in higher yields. Biotransformation with sporulated surface cultures was also monitored in Petri dishes and the same solid medium, Sabouraud Dextrose Agar (SD A), was used. In the solid agar medium inoculated with spores of Mucor ramannianus, first germination of the spores and then mycelial growth took place. After 1 week, the surfaces of Petri dishes were covered with spores and biotransformation reaction had started. However, there is no report on the biotransformation of (-)-menthol using Mucor ramannianus. Six isolates (93.6%) found Mucor ramannianus as a biocatalyst and biotransformation of (–)–menthol was investigated. The pathways involved in the biotransformation of (–)–menthol by two main products are also discussed.
Despite the unfavourable influence of mycotoxins on human and animal health and few toxi- cological aspects that have been documented, about these biologically active substances has not been explored. Aiming at more knowledge and a better understanding of the effects and mechanism of mycotoxin action in mammals would provide the basics for developing strategies to restrain different mycotoxicoses. One of the processes not fully understood is biotransformation, to which mycotoxins are subjected the animal organism. Biotransformation is the conversion of mycotoxins to non-toxic metabolites and occurs mostly in the intestinal mucosal membrane and liver, although other tissues and systems also take part in this process. Mycotoxin biotransformation reactions can be considered bioinactivation or detoxication, but mycotoxin biotransformation processes could also result in products more toxic than the mycotoxin. It can be concluded from research studies that our knowledge of mycotoxin biotransformation is scarce.
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