Thioalkalicoccus limnaeus gen. nov., sp. nov., a new alkaliphilic purple sulfur bacterium with bacteriochlorophyll b

Four strains of purple sulfur bacteria containing bacteriochlorophyll b were isolated from cyanobacterial mats of soda lakes in the steppe of south-east Siberia, Russia. Cells of all strains were cocci without gas vesicles. Eventually, cells with flagella were seen in the electron microscope, but motile cells were observed very rarely in cultures. Internal photosynthetic membranes were of the tubular type. Photosynthetic pigments were bacteriochlorophyll b and carotenoids with spectral characteristics similar to 3,4,3',4'-tetrahydrospirilloxanthin. The bacteria were obligately phototrophic and strictly anaerobic. Hydrogen sulfide and elemental sulfur were used as photosynthetic electron donors. Thiosulfate was not used. During growth on sulfide, sulfur globules were formed as intermediate oxidation products, deposited inside the cells and centrally located. In the presence of sulfide and sodium bicarbonate, acetate, malate, propionate, pyruvate, succinate, fumarate and yeast extract were photoassimilated. Growth factors were not required. The new bacterium is an obligate alkaliphile growing at pH 8-10 with an optimum at pH 9. It showed good growth up to 6.0% sodium chloride and up to 8.5% sodium carbonates. Phenotypically, it is similar to Thiococcus pfennigii, but different by virtue of its alkaliphily and salt tolerance. The DNA G+C content was 63.6-64.8 mol %, compared to 69.4-69.9 mol % for Thiococcus pfennigii. The 16S rDNA sequence of strain A26T was approximately 92% similar to that of Thiococcus pfennigii DSM 226 and therefore a new genus and species name, Thioalkalicoccus limnaeus gen. nov. and sp. nov., are proposed for the new bacteriu

Thiorhodospira sibirica gen. nov., and sp. nov., a new alkaliphilic purple sulfur bacterium from a Siberian soda lake

A new purple sulfur bacterium was isolated from microbial films on decaying plant mass in the near-shore area of the soda lake Malyi Kasytui (pH 9.5, 0.2% salinity) located in the steppe of the Chita region of south-east Siberia. Single cells were vibrioid- or spiral-shaped (3-4 microns wide and 7-20 microns long) and motile by means of a polar tuft of flagella. Internal photosynthetic membranes were of the lamellar type. Lamellae almost filled the whole cell, forming strands and coils. Photosynthetic pigments were bacteriochlorophyll a and carotenoids of the spirilloxanthin group. The new bacterium was strictly anaerobic. Under anoxic conditions, hydrogen sulfide and elemental sulfur were used as photosynthetic electron donors. During growth on sulfide, sulfur globules were formed as intermediate oxidation products. They were deposited outside the cytoplasm of the cells, in the peripheral periplasmic space and extracellularly. Thiosulfate was not used. Carbon dioxide, acetate, pyruvate, propionate, succinate, fumarate and malate were utilized as carbon sources. Optimum growth rates were obtained at pH 9.0 and optimum temperature was 30 degrees C. Good growth was observed in a mineral salts medium containing 5 g sodium bicarbonate l-1 without sodium chloride. The new bacterium tolerated up to 60 g sodium chloride l-1 and up to 80 g sodium carbonates l-1. Growth factors were not required. The DNA G + C composition was 56.0-57.4 mol%. Based on physiological, biochemical and genetic characteristics, the newly isolated bacterium is recognized as a new species of a new genus with the proposed name Thiorhodospira sibirica

Hydrometallurgical Technology for Processing of Galvanic Sludges

The problem of processing galvanic sludges, formed as a result of neutralization of technological solutions and wastewater containing heavy non-ferrous metals is considered. At present, sludges are transported to disposal area and are not used in any way. Typically, such sludges contain significant amounts of chromium and nickel, which creates environmental hazard. Investigated sludge contains up to 6.6% Ni and up to 7.4% Cr. The hydrometallurgical technology for processing of these sludges has been developed. Solutions of sulfuric acid and ammonia were used as lixiviants. It is shown that when using a solution of sulfuric acid with pH=1.5, extraction of up to 93.3% Cu, 70.2 Ni, 90.3 Zn is achieved. For selective recovery of nickel from leachates the process of sorption concentration by Lewatit TP207 is proposed. © Published under licence by IOP Publishing Ltd

Ectothiorhodospira variabilis, sp. nov., an alkaliphilic and halophilic purple sulfur bacterium from soda lakes

During studies of moderately halophilic strains of Ectothiorhodospira from steppe soda lakes, we found a novel group of bacteria related to Ectothiorhodospira haloalkaliphila with salt optima at 50–80 g NaCl l”1. Phylogenetic analysis using 16S rRNA gene sequences of strains from soda lakes in Mongolia, Egypt and Siberia revealed separation of the group of new isolates from other Ectothiorhodospira species, including the closely related Ect. haloalkaliphila. DNA–DNA hybridization studies demonstrated that the new isolates form a homogeneous group at the species level, but at the same time are distinct from related species such as Ect. haloalkaliphila, Ect. vacuolata, Ect. shaposhnikovii and Ect. marina. The new isolates are considered to be strains of a novel species, for which the name Ectothiorhodospira variabilis sp. nov. is proposed, with the type strain WN22T (5VKM B-2479T 5DSM 21381T). Photosynthetic pigments of the novel species are bacteriochlorophyll a and carotenoids of the spirilloxanthin series with spirilloxanthin and derivatives thereof, together with small amounts of lycopene and rhodopin. Gas vesicles are formed by most of the strains, particularly in media containing yeast extract (0.5 g l”1) and acetate (0.5–2.0 g l”1). Sequence analysis of nifH (nitrogenase) and cbbL (RuBisCO) confirmed the assignment of the strains to the genus Ectothiorhodospira and in particular the close relationship to Ect. haloalkaliphila. The novel species Ect. variabilis is found in soda lakes separated by great geographical distances and is an alkaliphilic and halophilic bacterium that tolerates salt concentrations up to 150–200 g NaCl l”1

Study of Nickel Sorption Recovery from Leachates of Oxidized Nickel Ores

Проведены исследования сорбции никеля из сернокислых растворов выщелачивания окисленных никелевых руд. Показано, что иониты с бис-пиколиламиновыми и иминодиацетатными группами проявляют способность к сорбции ионов никеля (II) даже на фоне преобладающих концентраций ионов железа (III). Наиболее эффективным оказался ионит Lewatit TP220. Сорбция никеля с удовлетворительными показателями протекает как в варианте сорбционного выщелачивания, так и извлечения из осветленных растворов. При сорбции из пульпы емкость по никелю составила 5,44 мг/г, по железу 25,17 мг/г.Studies of nickel sorption from sulfuric acid leachates of oxidized nickel ores have been carried out. It was shown that ion exchangers with bis-picolylamine and iminodiacetate groups exhibit the ability to adsorb nickel (II) ions even against the background of prevailing concentrations of iron (III) ions. The most effective was the ion exchanger Lewatit TP220 and, to a lesser extent, Lewatit TP207. Sorption of nickel with satisfactory performance occurs both in the variant of resin-in-pulp and from clarified solutions. During sorption from the pulp, the capacity for nickel was 5.44 mg/g, for iron, 25.17 mg/g

Optimization of medium composition and study of growth stages of <i>Mycoplasma bovis</i> “Kaluga 2020” isolate

Mycoplasma bovis is considered one of bovine mycoplasmosis pathogens responsible for respiratory diseases, mastitis, arthritis and keratoconjunctivitis. The paper presents results of the study on optimizing the component composition of the culture medium for Mycoplasma bovis “Kaluga 2020” isolate, as well as the study of this pathogen’s growth stages. The color-changing units assay and the culture method combined with colony-forming unit quantification were used for determination of Mycoplasma activity. It was found that when cultured in an optimized nutrient medium based on modified Hayflick broth, the microorganism enters a logarithmic growth phase after first 24 hours ofgrowth, in 72 hours the Mycoplasma culture enters astability phase, and adecline phase is recorded in 84 hours. The effect of percentage content of glucose, fresh yeast extract and horse serum in the nutrient medium on accumulation of Mycoplasma bovis “Kaluga2020” isolate was evaluated using the one-factor-at-a-time approach. It was found that the greatest effect on Mycoplasma accumulation was exerted by such growth factors as fresh yeast extract and horse serum in the nutrient medium (p &lt; 0.05), while changes in the amount of glucose did not stimulate Mycoplasma bovis growth. Based on results of the conducted studies, the appropriate composition was determined and the optimal content of growth factors in the medium for culturing Mycoplasma bovis “Kaluga 2020” isolate was selected: 12.5%of fresh yeast extract and 25% of horse serum. The use of the optimized nutrient medium based on modified Hayflick broth allowed 5-fold increase in accumulation of Mycoplasma biomass (3.98 × 109CFU/ml)compared to the standard medium (0.79 × 109CFU/ml)