The hydrogen-producing bacterium SP-H2 was isolated from a thermophilic acidogenic reactor inoculated with municipal sewage sludge and processing a carbohydrate-rich simulated food waste. Based on the 16S rRNA gene sequence, the bacterium was identified as Thermoanaerobacterium thermosaccharolyticum. The maximum growth rate was observed at 55-60 degrees C and pH 7.5. The H-2-producing activity of the bacterium was studied using mono-, di-and tri-saccharides related to both hexoses (maltose, glucose, mannose, fructose, lactose, galactose, sucrose, raffinose, cellobiose) and pentoses (xylose and arabinose), as well as using real wastewaters (cheese whey, confectionery wastewater, sugar-beet processing wastewater). The highest H-2 yield was observed during dark fermentation (DF) of maltose (1.91 mol H-2/mol hexose or 77.8mmol H-2/L). Themaximum H-2 production rate was observed during DF of xylose (13.3ml H-2/g COD/h) and cellobiose (2.47mmol H-2/L/h). Themain soluble metabolite products were acetate, ethanol and butyrate. The acetate concentration had a statistically significant positive correlation with the H-2 content in biogas and the specificH(2) yield. Based on the results of the correlation analysis, it was tentatively assumed that in the formic acid (mixed-acid) type fermentation, the rate of H-2 production was higher than in the butyric acid type fermentation. With regard to real wastewater, cheese whey and confectionery wastewater were distinguished by a higher H-2 yield (152 ml H-2/g COD) and H-2 production rate (0.57mmol H-2/L/h), respectively. The highest concentrations of confectionery wastewater and cheese whey, at which the DF process took place, were 5915 and 7311mg COD/L, respectively. At the same time, SP-H-2 dominated in the microbial community, despite the presence of indigenous microorganisms in wastewater. Thus, T. thermosaccharolyticum SP-H2 is a promising strain for DF of carbohydrate-rich unsterile wastewater under thermophilic conditions. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Analysis of the taxonomic structure of prokaryotic microbial complexes of the saline soils in the Lake Elton area and their comparative characteristics were carried out for a soil catena along the Khara River flowing into the hypersaline Lake Elton. High-throughput pyrosequencing detected 11 bacterial and 2 archaeal phyla. Comparative analysis of community structure revealed the differences between Solonchaks located at the river flood land and Kastanozems at the slope and top of the river terrace. The patterns of occurrence were described for six predominant phyla (Euryarchaeota, Thaumarchaeota, Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria). For the floodplain soils, the relations between the distribution of Euryarchaeota, Thaumarchaeota, Firmicutes, Actinobacteria, Proteobacteria and soil salinity as well as soil pH were described. Occurrence of members of the phyla Euryarchaeota, Thaumarchaeota, Firmicutes, Actinobacteria, and Proteobacteria in flood land soils was shown to depend on the soil salinity and pH. Members of the phyla Actinobacteria and Firmicutes were shown to predominate in Gleyic Kastanozems . Cloning of the 16S rRNA gene revealed high diversity within the genus Streptomyces (Actinobacteria). A number of the isolated streptomycete clones were homologous to the known antibiotic producers, which indicates that soils of this area are promising for further biotechnological screening.

— The genes encoding carbonic anhydrase (CA) were found in all anoxygenic purple bacteria. The genes of α- and β-CA were found in purple nonsulfur bacteria of the class Alphaproteobacteria: Rhodospirillum rubrum , Rhodospirillum fulvum , Rhodoblastus acidophilus , and Rhodopseudomonas palustris . The alphaproteobacteria Rhodomicrobium vannielii , Blastochloris viridis , Rhodobacter sphaeroides , Rhodobacter capsulatus , Rhodobacter veldkampii , Rhodovulum euryhalinum , and Rhodovulum sulfidophilum possessed only the β-CA genes. Both nonsulfur purple bacteria of the class Betaproteobacteria ( Rubrivivax gelatinosus ) and purple sulfur bacteria (class Gammaproteobacteria ) contained the α- and β-CA. No CA genes were found in green sulfur bacteria Chlorobaculum limnaeum and Chlorobaculum parvum , as well as in filamentous green nonsulfur bacteria Chloroflexus aurantiacus . However, the β-CA gene was revealed in Oscillochloris trichoides , which belonged to the latter taxonomic group. No γ-CA genes were detected in the genomes of the phototrophic bacteria studied in the present work. Although CA genes were present in all purple bacteria, the α- and β-CA activity was observed only in four species of purple nonsulfur Alphaproteobacteria : Rhodospirillum rubrum , Rhodopseudomonas palustris , Rhodoblastus acidophilus , and Rhodospirillum fulvum . These bacteria are able to synthesize CA under both photoautotrophic and photoheterotrophic conditions in the media with acetate, malate, or fructose. These bacteria (except for Rhodospirillum fulvum , which is unable to grow under aerobic conditions), also exhibit CA activity when grown under aerobic conditions in the dark.

The goal of the present work was to investigate the composition of microbial communities developing on polyethylene terephthalate (PET) samples immersed in aqueous media of various origin (marine, freshwater, and industrial; the latter was periodically treated with an antimicrobial agent) in three different climatic zones. High-throughput sequencing of the V3–V4 region of the 16S rRNA gene was used to obtain gene libraries for each of the samples. Members of the phyla Bacteroidetes, Gammaproteobacteria, and Alphaproteobacteria predominated in the libraries from all three groups of the samples. However, the quantitative ratios of both the dominant and the minor groups in the libraries were different, and within the groups the ratios depended on exposure time and antimicrobial treatment. Both the groups of libraries from the samples of different origin and individual communities within the groups exhibited differences at the genus level. The functional characteristics of prokaryotes in the 16S rRNA gene libraries were predicted using iVikodak. Microbial communities of industrial water, in which members of the genera Pseudomonas and Acidovorax were detected in silico were shown to be potentially capable of degrading PET samples; these organisms possess the enzymes for catabolism of terephthalic acid, the intermediate metabolite of this process. Photomicrography confirmed local PET degradation after exposure in industrial water, while no PET degradation was observed in seawater.

Five phylogenetically similar monocultures of mesophilic filamentous anoxygenic phototrophic bacteria (FAPB) were isolated from microbial mats of low-mineral (5–28 g/L) alkaline lakes in Buryat Republic, Transbaikalia and Mongolia, as well as from biofilms of an alkaline sulfide spring (3 g/L) of the Umhei hydrothermal system (Buryat Republic). New isolates were characterized by short trichomes (15–30 μm long and ∼1 μm in diameter), straight, curved, or wavy, surrounded by a thin iron-sorbing mucous sheath. Gliding motion of the trichomes was not observed. The trichomes formed bunches consisting of several filaments. Trichomes multiply by the separation of short fragments or single cells from the parental trichome. The cells in the filaments were elongated; they contained chlorosomes, gas vesicles, poly-β-hydroxybutyrate granules, and small polyphosphate inclusions. Bacteria contained bacteriochlorophylls c and a and γ-carotene. Absorption maxima of the pigments in the cells were observed at 462, (shoulder at 515), 742, 805, and 863 nm. The organisms were strict anaerobes capable of photoautotrophic growth with sulfide as an electron donor. Elemental sulfur emerged into the medium as a result of sulfide photooxidation. The organisms were tolerant to sulfide (up to 8 mM). Best growth occurred at pH 8.0, 3–15 g/L NaCl, and 1–5 g/L sodium bicarbonate. According to phylogenetic analysis, the 16S rRNA gene sequences of the FAPB isolates formed a separate cluster most closely related to the species cluster of the family Oscillochloridaceae, suborder Chloroflexinae, order Chloroflexales, class Chloroflexi. The differences with the closest 16S rRNA gene sequences of the known FAPB were 9–10%. The formal description of a new taxon, Candidatus’ Chloroploca asiatica’ gen. nov., sp. nov., is provided.

Genetic constructs coding for the fusion of the Mam12 membrane protein from the magnetotactic bacteria Magnetospirilium magnetotacticum with one B-domain (mb) or two B or Z domains (mbb and mzz, respectively) of Staphylococcus aureus protein A have been synthesized. Expression, fractionation, and purification of fusion proteins have been performed, and the activity of the modified proteins has been characterized. ELISA results showed that all modified proteins displayed immunoglobulin-binding activity.