A novel obligately aerobic heterotrophic bacterium belonging to the genus Xanthobacter, strain Z-0055, was isolated from the bacterial community of dystrophic waters formed by xylotrophic fungi grown on decaying spruce wood. The cells are small (0.4 ±0.7 fum), ovoid, grarrmegative, and nonmotile. The strain reproduces by nonuniform division. Strain Z-0055 is a moderately acidophilic microorganism and grows in a pH range of 4.8–6.8, with an optimum at pH 5.5. The temperature range for growth is 10–28°C, with an optimum at 20°C. The bacterium utilizes salts of organic acids (citrate, oxalate, succinate, and gluconate), as well as xylose and xylan as carbon and energy sources. No growth was detected at NaCl concentrations higher than 1.5 g/l. The DNA G+C base content is 63.6 mol %. According to phylogenetic analysis of the 16S rRNA gene sequences, strain Z-0055 belongs to the cluster containing X. flavus, X. aminoxidans, X. autotrophicus, and X. viscosus. The levels of similarity between the studied strain and these species are almost the same (96.0–97.0%). The genetic and ecophysiological properties of strain Z-0055 support classification of this acid-tolerant inhabitant of oligotrophic waters within the genus Xanthobacter as a new species X. xylophilus sp. nov.

A new species of the genus Ancylobacter, exemplified by strain Z-0056, was isolated from dystrophic humified waters formed by xylotrophic fungi grown on decaying spruce wood. The cells of strain Z-0056 (0.65–0.9 μm) are coccoid, gram-negative, with fimbriae, and nonmotile. The strain is pleomorphic and reproduces by nonuniform division. Strain Z-0056 is an aerobic organoheterotroph and a mesophilic and moderately acidophilic oligotrophic microorganism. As an inhabitant of dystrophic ultrafresh waters, strain Z-0056 is sensitive to NaCl. The bacterium utilizes organic acids (acetate, pyruvate, oxalate, gluconate, malate, succinate, and citrate), as well as xylose and xylan. The microorganism grows in a pH range of 4.0–8.0, with an optimum at pH 5.5. The temperature range for growth is 15–25°C, with an optimum at 20°C. According to its ecophysiological properties, strain Z-0056 belongs to the group of ombrophilic dissipotrophs. The DNA G+C base content is 66.8 mol %. According to phylogenetic analysis, strain Z-0056 belongs to the genus Ancylobacter. Strain Z-0056 showed the highest similarity (98.3%) with the type strain of the species A. oerskovii. The phenotypic and phylogenetic properties of strain Z-0056 support classification of this microorganism within the genus Ancylobacter as the novel species Ancylobacter abiegnus sp. nov.

Two novel strains of budding bacteria, Z-0071T and Z-0072, were isolated from dystrophic humified waters formed by xylotrophic fungi in the course of spruce wood degradation. The cells of both strains

An isolate of prosthecate bacteria was isolated from the takyr soil of a rice field on the Akdala massif (Kazakhstan) and designated as strain 22^T. Strain 22^T was represented by gram-negative, aerobic, motile, oxidase and catalase-positive bacteria. Cells of this strain formed numerous prosthecae extending in different directions from the cell surface. Bacteria had a dimorphic life cycle, with two different morphological types of cells. The prosthecae may be short (i.e., less than 1.0 µm long) or long (i.e., more than 2.0 µm long). Cells reproduced by budding and grew within the pH range of 6.5–8.5 and at 28–30°C. Major cellular fatty acids were C18:1 ω7, C16:0, C19:1 branched, and C16:1 ω7. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain 22^T shared the highest gene sequence similarity with Prosthecomicrobium hirschii 16^T (99.9%) and formed a common branch on the phylogenomic tree with P. hirschii 16^T and Siculibacillus lacustris SA-279^T. This branch was only distantly related to the phylogenetic lineage defined by the type species of the genus Prosthecomicrobium, P. pneumaticum ATCC 23633^T, thus indicating a polyphyletic nature of the genus Prosthecomicrobium. The average nucleotide identity (ANI) and in silico DNA–DNA hybridization (dDDH) values between strain 22^T and the most closely related species P. hirschii 16^T were 93.6 and 47.6%, respectively, and were below the threshold accepted for species demarcation. Based on the results of phylogenetic analysis, strains 22^T and 16^T should be assigned to the Ancalomicrobiaceae family, with introduction of a novel genus Prosthecodimorpha gen. nov. The G + C content of the genome of strain 22^T was 61.9%. Strain 22^T represented a novel species in a novel genus, for which the name Prosthecodimorpha staleyi gen. nov., sp. nov. is proposed, with the type strain 22^T (=VKM B-3576^T = UQM 41461^T = DSMZ 113594^T).

Aim. The aim of the work was to study the possibility of using an environmentally friendly strain of yeast of the genus Rhodotorula for the bioconversion into fodder carotenoid‐containing biomass of the secondary product of processing pea flour into a protein concentrate (whey).Material and Methods. We used a new strain of Rhodotorula mucilaginosa 111 and by‐products of processing pea and chickpea flour into protein concentrates and potatoes into starch (whey). We used standard and special methods for the analysis of serum and microbial‐vegetable concentrate (FMVC) namely: chemical; biochemical; microbiological; and the determination of toxicity with ciliates.Results. Optimal conditions for growing R. mucilaginosa 111 on pea whey were determined (temperature 16.9°C, pH 7.8, amount of inoculum 1.85%). More biomass was synthesized on pea whey than on chickpea and potato whey – 81 g/dm³. The mass fraction of protein in the biomass is 58.90±3.03% on dry matter and the rate of essential amino acids is 119– 243%. Lipids included 20% saturated and 78% unsaturated fatty acids, linoleic acid – 45.26±0.70%, oleic – 24.04±0.76%, palmitoleic – 6.46±0.31%, palmitic – 13.70±0.81%. The yeast produced phytoin derivatives, torulene, β‐carotene, torularodin and phytoin. FMVC from pea whey stimulated the growth of ciliates Tetrahymena pyriformis by 29.1%, from chickpea whey (by 18.6% more intensively than distilled water), while potato whey reduced its growth rate.Conclusion. The dry biomass of the ecologically safe new yeast strain R. mucilaginosa 111 contained complete proteins, lipids, minerals, and carotenoids necessary for feeding animals. Thus liquid pea whey can be used for its biokonversions, while avoiding environmental pollution.

An Erratum to this paper has been published: https://doi.org/10.1134/S0026261724607589