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Large-scale land reclamation has become common in northwestern China; however, low soil fertility and poor soil water-holding capacity limit agricultural production on these reclaimed lands, requiring increased fertilizer and irrigation inputs. Biochar, produced from agricultural waste, has shown potential in improving soil quality and water-holding capacity. In this two-year field study (2021 and 2022), we investigated the effects of biochar produced from maize straw on soil properties and grain yield of foxtail millet grown on newly reclaimed land. Three biochar treatments (3000, 4500, and 6000 kg ha−1) were compared to a control (CK) with no biochar application. Biochar application resulted in increased soil organic matter, total phosphorus, total nitrogen, soil enzyme activity, and soil organic acid content. It also significantly decreased soil pH and bulk density. Compared with the CK, biochar increased available nitrogen from 29.7% to 108% in 2021 and 37.0% to 88.4% in 2022. Similarly, biochar increased available phosphorus from 64.7% to 143% in 2021 and 41.9% to 96.5% in 2022. Grain yields ranged from 3092 to 4753 kg ha−1. Biochar treatments increased grain yield compared to the CK, ranging from 12.2% to 24.6% in 2021 and 27.1% to 53.7% in 2022. Correlation analysis revealed that soil pH was negatively related to soil oxalic acid content, phosphorus content, and sucrase activity. Available nitrogen and phosphorus contents were negatively related to soil bulk density and positively related to catalase activity. Soil water content was negatively correlated with soil bulk density and positively correlated with organic matter. In conclusion, biochar improved the rhizosphere soil pH and the effectiveness of soil fertility in the newly reclaimed soil, resulting in an enhanced grain yield of foxtail millet. [ABSTRACT FROM AUTHOR]

Porphyra haitanensis (P. haitanensis), an important food source for coastal residents in China, has a long history of medicinal and edible value. P. haitanensis polysaccharides are some of the main active ingredients in P. haitanensis. It is worth noting that P. haitanensis polysaccharides have a surprising and satisfactory biological activity, which explains the various benefits of P. haitanensis to human health, such as anti-oxidation, immune regulation, anti-allergy, and anticancer properties. Hence, a systematic review aimed at comprehensively summarizing the recent research advances in P. haitanensis polysaccharides is necessary for promoting their better understanding. In this review, we systematically and comprehensively summarize the research progress on the extraction, purification, structural characterization, modification, and biological activity of P. haitanensis polysaccharides and address the shortcomings of the published research and suggest area of focus for future research, providing a new reference for the exploitation of polysaccharides from P. haitanensis in the fields of medicine and functional foods. [ABSTRACT FROM AUTHOR]

Catabolite control protein A (CcpA) is a critical regulator in Gram-positive bacteria that orchestrates carbon metabolism by coordinating the utilization of different carbon sources. Although it has been widely proved that CcpA helps prioritize the utilization of glucose over other carbon sources, this global regulator's precise mechanism of action remains unclear. In this study, a mutant Bacillus licheniformis deleted for CcpA was constructed. Cell growth, carbon utilization, metabolites and the transcription of key enzymes of the mutant strain were compared with that of the wild-type one. It was found that CcpA is involved in the regulation of glucose concentration metabolism in Bacillus. At the same time, CcpA regulates glucose metabolism by inhibiting acetic acid synthesis and pentose phosphate pathway key gene zwF. The conversion rate of acetic acid is increased by about 3.5 times after ccpA is deleted. The present study provides a new mechanism of carbon metabolism and acetic acid balance regulated by CcpA. On the one hand, this work deepens the understanding of the regulatory function of CcpA and provides a new view on the regulation of glucose metabolism. On the other hand, it is helpful to the transformation of B. licheniformis chassis microorganisms. [ABSTRACT FROM AUTHOR]

Bacteria and yeast are being intensively used to produce biofuels and high-added-value products by using plant biomass derivatives as substrates. The number of microorganisms available for industrial processes is increasing thanks to biotechnological improvements to enhance their productivity and yield through microbial metabolic engineering and laboratory evolution. This is allowing the traditional industrial processes for biofuel production, which included multiple steps, to be improved through the consolidation of single-step processes, reducing the time of the global process, and increasing the yield and operational conditions in terms of the desired products. Engineered microorganisms are now capable of using feedstocks that they were unable to process before their modification, opening broader possibilities for establishing new markets in places where biomass is available. This review discusses metabolic engineering approaches that have been used to improve the microbial processing of biomass to convert the plant feedstock into fuels. Metabolically engineered microorganisms (MEMs) such as bacteria, yeasts, and microalgae are described, highlighting their performance and the biotechnological tools that were used to modify them. Finally, some examples of patents related to the MEMs are mentioned in order to contextualize their current industrial use. [ABSTRACT FROM AUTHOR]

Manganese (Mn) oxides are widespread on the surface environments of the modern Earth. The role of microbial activities in the formation of Mn oxides has been discussed for several decades. However, the mechanisms of microbial Mn oxidation, and its role in complex microbial communities in natural environments, remain uncertain. Here, we report the geochemical, mineralogical, and metagenomic evidence for biogenic Mn oxides, found in Japanese hot spring sinters. The low crystallinity of Mn oxides, and their spatial associations with organic matter, support the biogenic origin of Mn oxides. Specific multicopper oxidases (MCOs), which are considered Mn-oxidizing enzymes, were identified using metagenomic analyses. Nanoscale nuggets of copper sulfides were, also, discovered in the organic matter in Mn-rich sinters. A part of these copper sulfides most likely represents traces of MCOs, and this is the first report of traces of Mn-oxidizing enzyme in geological samples. Metagenomic analyses, surprisingly, indicated a close association of Mn oxides, not only in aerobic but also in anaerobic microbial communities. These new findings offer the unique and unified positions of Mn oxides, with roles that have not been ignored, to sustain anaerobic microbial communities in hot spring environments. [ABSTRACT FROM AUTHOR]

The bioleaching of manganese present in mining waste after metal extraction can be catalyzed by Leptospirillum (L.) ferriphilum by allowing atmospheric carbon dioxide to be used in this autotrophic process and generating the subsequent recovery of silver. Bioleaching of metals is widely performed in agitated tanks; therefore, it is important to assess the mass transfer capacity of gaseous substrates, such as carbon dioxide, during the microbial processes. The main objective of this research was to evaluate the effects of the presence and concentration of a transfer vector (silicone oil) added into a stirred-tank bioreactor during bioleaching of mining tailings catalyzed by L. ferriphilum, determined by the combined gas/oil mass transfer coefficient of carbon dioxide (kLaCO2) into the aqueous phase. The experiments were carried out following a Box–Behnken experimental design, evaluating the concentrations of mining waste (30%, 40%, and 50%), Fe2+, serving as electron donor (2, 8, and 14 g/L), and silicon oil (0%, 5%, and 10%). A significant increase in kLaCO2 was observed after the addition of the transfer vector by comparing the lowest kLaCO2 value of 1.68 h−1 (obtained at 50% pulp, 8 g/L Fe2+, and 0% silicone oil) and the highest kLaCO2 of 21.81 h−1 (obtained at 30% pulp, 2 g/L Fe2+, 5% silicone oil). The results showed statistically significant differences in the transfer of carbon dioxide during the bioleaching process with a transfer vector. [ABSTRACT FROM AUTHOR]

Simple Summary: SAR324, newly proposed as its own candidate phylum, is a diverse and globally abundant bacterial group living in a wide range of environments, from deep-sea hydrothermal vents and brine pools to the epipelagic regions of the global oceans and terrestrial aquifers. The different SAR324 clades harbor a diverse array of genes and pathways well adapted to their respective environments. This metabolic flexibility explains the ubiquitous presence and the importance of SAR324 in global biogeochemical cycles. The bacterial SAR324 cluster is ubiquitous and abundant in the ocean, especially around hydrothermal vents and in the deep sea, where it can account for up to 30% of the whole bacterial community. According to a new taxonomy generated using multiple universal protein-coding genes (instead of the previously used 16S rRNA single gene marker), the former Deltaproteobacteria cluster SAR324 has been classified since 2018 as its own phylum. Yet, very little is known about its phylogeny and metabolic potential. We downloaded all publicly available SAR324 genomes (65) from all natural environments and reconstructed 18 new genomes using publicly available oceanic metagenomic data and unpublished data from the waters underneath the Ross Ice Shelf. We calculated a global SAR324 phylogenetic tree and identified six clusters (namely 1A, 1B, 2A, 2B, 2C and 2D) within this clade. Genome annotation and metatranscriptome read mapping showed that SAR324 clades possess a flexible array of genes suited for survival in various environments. Clades 2A and 2C are mostly present in the surface mesopelagic layers of global oceans, while clade 2D dominates in deeper regions. Our results show that SAR324 has a very versatile and broad metabolic potential, including many heterotrophic, but also autotrophic pathways. While one surface water associated clade (2A) seems to use proteorhodopsin to gain energy from solar radiation, some deep-sea genomes from clade 2D contain the complete Calvin–Benson–Bassham cycle gene repertoire to fix carbon. This, in addition to a variety of other genes and pathways for both oxic (e.g., dimethylsulfoniopropionate degradation) and anoxic (e.g., dissimilatory sulfate reduction, anaerobic benzoate degradation) conditions, can help explain the ubiquitous presence of SAR324 in aquatic habitats. [ABSTRACT FROM AUTHOR]

White-rot fungi can degrade all lignocellulose components due to their potent lignin and cellulose-degrading enzymes. In this study, five white-rot fungi, Trametes versicolor, Trametes pubescens, Ganoderma adspersum, Ganoderma lipsiense, and Rigidoporus vitreus were tested for endoglucanase, laccase, urease, and glucose-6-phosphate (G6P) production when grown with malt extract and nanocellulose in the form of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidized cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC). Results show that temperature plays a key role in controlling the growth of all five fungi when cultured with malt extract alone. Endoglucanase activities were highest in cultures of G. adspersum and G. lipsiense and laccase activities were highest in cultures of T. versicolor and R. vitreus. Urease activities were highest in cultures of G. adspersum, G. lipsiense, and R. vitreus. Glucose-6-phosphate levels also indicate that cells were actively metabolizing glucose present in the cultures. These results show that TEMPO-oxidized CNF and CNC do not inhibit the production of specific lignocellulose enzymes by these white-rot fungi. The apparent lack of enzymatic inhibition makes TEMPO-oxidized CNF and CNC excellent candidates for future biotechnological applications in combination with the white-rot fungi studied here. [ABSTRACT FROM AUTHOR]

Microbial community proteomics, also termed metaproteomics, is an emerging field within the area of microbiology, which studies the entire protein complement recovered directly from a complex environmental microbial community at a given point in time. Although it is still in its infancy, microbial community proteomics has shown its powerful potential in exploring microbial diversity, metabolic potential, ecological function and microbe-environment interactions. In this paper, we review recent advances achieved in microbial community proteomics conducted in diverse environments, such as marine and freshwater, sediment and soil, activated sludge, acid mine drainage biofilms and symbiotic communities. The challenges facing microbial community proteomics are also discussed, and we believe that microbial community proteomics will greatly enhance our understanding of the microbial world and its interactions with The environment. [ABSTRACT FROM AUTHOR]

The most exciting advances in biohydrometallurgy are occurring in the field of microbiology. The two main technologies employed in biohydrometallurgy, agitated tanks for the processing of refractory concentrates and heaps and dumps for the processing of low-grade ores, are technologically sound and widely practised at commercial scale, but their development began at a time when very little was known of the microorganisms that assisted metals extraction from sulfide ores. During and subsequent to those developments it has been shown that microbial communities in metals extraction are more diverse than originally thought, and extremely robust and adaptable to different and variable environments. Recent advances in genomics and proteomics, exploiting hugely increased computing power and speed, have made it possible to describe not only which microorganisms are present in bioleaching systems, but also what physiological functions are being exercised. The body of knowledge being acquired through the application of molecular biology methods will be used increasingly to monitor microbial behaviour, optimise conditions for more appropriate microbiological activity and/or infer the "microbiological health" of bioreactors (tanks and heaps). [ABSTRACT FROM AUTHOR]

Over the past decade, a variety of ionic liquids have emerged as greener solvents for use in the chemical manufacturing industries. Their unique properties have attracted the interest of chemists worldwide to employ them as replacement for conventional solvents in a diverse range of chemical transformations including biotransformations. Biocatalysts are often regarded as green catalysts compared to conventional chemical catalysts in organic synthesis owing to their properties of low toxicity, biodegradability, excellent selectivity and good catalytic performance under mild reaction conditions. Similarly, a selected number of specific ionic liquids can be considered as greener solvents superior to organic solvents owing to their negligible vapor pressure, low flammability, low toxicity and ability to dissolve a wide range of organic and biological substances, including proteins. A combination of biocatalysts and ionic liquids thus appears to be a logical and promising opportunity for industrial use as an alternative to conventional organic chemistry processes employing organic solvents. This article provides an overview of recent developments in this field with special emphasis on the application of more sustainable enzyme-catalyzed reactions and separation processes employing ionic liquids, driven by advances in fundamental knowledge, process optimization and industrial deployment. [ABSTRACT FROM AUTHOR]

The filamentous cyanobacterium Anabaena variabilis ATCC 29413 fixes nitrogen under aerobic conditions in specialized cells called heterocysts that form in response to an environmental deficiency in combined nitrogen. Nitrogen fixation is mediated by the enzyme nitrogenase, which is very sensitive to oxygen. Heterocysts are microxic cells that allow nitrogenase to function in a filament comprised primarily of vegetative cells that produce oxygen by photosynthesis. A. variabilis is unique among well-characterized cyanobacteria in that it has three nitrogenase gene clusters that encode different nitrogenases, which function under different environmental conditions. The nif1 genes encode a Mo-nitrogenase that functions only in heterocysts, even in filaments grown anaerobically. The nif2 genes encode a different Mo-nitrogenase that functions in vegetative cells, but only in filaments grown under anoxic conditions. An alternative V-nitrogenase is encoded by vnf genes that are expressed only in heterocysts in an environment that is deficient in Mo. Thus, these three nitrogenases are expressed differentially in response to environmental conditions. The entire nif1 gene cluster, comprising at least 15 genes, is primarily under the control of the promoter for the first gene, nifB1. Transcriptional control of many of the downstream nif1 genes occurs by a combination of weak promoters within the coding regions of some downstream genes and by RNA processing, which is associated with increased transcript stability. The vnf genes show a similar pattern of transcriptional and post-transcriptional control of expression suggesting that the complex pattern of regulation of the nif1 cluster is conserved in other cyanobacterial nitrogenase gene clusters. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs), entirely composed of cations and anions, are liquid solvents at room temperature. They are interesting due to their low vapor pressure, high polarity and thermostability, and also for the possibility to fine-tune their physicochemical properties through modification of the chemical structures of their cations or anions. In recent years, ILs have been widely used in biotechnological fields involving whole-cell biotransformations of biodiesel or biomass, and organic compound synthesis with cells. Research studies in these fields have increased from the past decades and compared to the typical solvents, ILs are the most promising alternative solvents for cell biotransformations. However, there are increasing limitations and new challenges in whole-cell biotransformations with ILs. There is little understanding of the mechanisms of ILs' interactions with cells, and much remains to be clarified. Further investigations are required to overcome the drawbacks of their applications and to broaden their application spectrum. This work mainly reviews the applications of ILs in whole-cell biotransformations, and the possible mechanisms of ILs in microbial cell biotransformation are proposed and discussed. [ABSTRACT FROM AUTHOR]

The last few years have witnessed the emergence of alternative measures to control plant parasitic nematodes (PPNs). We briefly reviewed the potential of compost and the direct or indirect roles of soil-dwelling organisms against PPNs. We compiled and assessed the most intensively researched factors of suppressivity. Municipal green waste (MGW) was identified and profiled. We found that compost, with or without beneficial microorganisms as biocontrol agents (BCAs) against PPNs, were shown to have mechanisms for the control of plant parasitic nematodes. Compost supports a diverse microbiome, introduces and enhances populations of antagonistic microorganisms, releases nematicidal compounds, increases the tolerance and resistance of plants, and encourages the establishment of a "soil environment" that is unsuitable for PPNs. Our compilation of recent papers reveals that while the scope of research on compost and BCAs is extensive, the role of MGW-based compost (MGWC) in the control of PPNs has been given less attention. We conclude that the most environmentally friendly and long-term, sustainable form of PPN control is to encourage and enhance the soil microbiome. MGW is a valuable resource material produced in significant amounts worldwide. More studies are suggested on the use of MGWC, because it has a considerable potential to create and maintain soil suppressivity against PPNs. To expand knowledge, future research directions shall include trials investigating MGWC, inoculated with BCAs. [ABSTRACT FROM AUTHOR]

Polyhydroxybutyrate (PHB) is a natural polyester synthesized by several microorganisms. Moreover, it has excellent biodegradability and is an eco-friendly material because it converts water and carbon dioxide as final decomposition products. However, the applications of PHB are limited because of its stiffness and brittleness. Because cellulose nanocrystals (CNCs) have excellent intrinsic mechanical properties such as high specific strength and modulus, they may compensate for the insufficient physical properties of PHB by producing their nanocomposites. In this study, natural polyesters were extracted from Cupriavidus necator fermentation with CNCs, which were well-dispersed in nitrogen-limited liquid culture media. Fourier-transform infrared spectroscopy results revealed that the additional O–H peak originating from cellulose at 3500–3200 cm−1 was observed for PHB along with the C=O and –COO bands at 1720 cm−1. This suggests that PHB–CNC nanocomposites could be readily obtained using C. necator fermented in well-dispersed CNC-supplemented culture media. [ABSTRACT FROM AUTHOR]

The existence of microbial activity hotspots in temperate regions of Earth is driven by soil heterogeneities, especially the temporal and spatial availability of nutrients. Here we investigate whether microbial activity hotspots also exist in lithic microhabitats in one of the most arid regions of the world, the Atacama Desert in Chile. While previous studies evaluated the total DNA fraction to elucidate the microbial communities, we here for the first time use a DNA separation approach on lithic microhabitats, together with metagenomics and other analysis methods (i.e., ATP, PLFA, and metabolite analysis) to specifically gain insights on the living and potentially active microbial community. Our results show that hypolith colonized rocks are microbial hotspots in the desert environment. In contrast, our data do not support such a conclusion for gypsum crust and salt rock environments, because only limited microbial activity could be observed. The hypolith community is dominated by phototrophs, mostly Cyanobacteria and Chloroflexi, at both study sites. The gypsum crusts are dominated by methylotrophs and heterotrophic phototrophs, mostly Chloroflexi, and the salt rocks (halite nodules) by phototrophic and halotolerant endoliths, mostly Cyanobacteria and Archaea. The major environmental constraints in the organic-poor arid and hyperarid Atacama Desert are water availability and UV irradiation, allowing phototrophs and other extremophiles to play a key role in desert ecology. [ABSTRACT FROM AUTHOR]

Second-generation biofuel production is in high demand, but lignocellulosic biomass' complexity impairs its use due to the vast diversity of enzymes necessary to execute the complete saccharification. In nature, lignocellulose can be rapidly deconstructed due to the division of biochemical labor effectuated in bacterial communities. Here, we analyzed the lignocellulolytic potential of a bacterial consortium obtained from soil and dry straw leftover from a sugarcane milling plant. This consortium was cultivated for 20 weeks in aerobic conditions using sugarcane bagasse as a sole carbon source. Scanning electron microscopy and chemical analyses registered modification of the sugarcane fiber's appearance and biochemical composition, indicating that this consortium can deconstruct cellulose and hemicellulose but no lignin. A total of 52 metagenome-assembled genomes from eight bacterial classes (Actinobacteria, Alphaproteobacteria, Bacilli, Bacteroidia, Cytophagia, Gammaproteobacteria, Oligoflexia, and Thermoleophilia) were recovered from the consortium, in which ~46% of species showed no relevant modification in their abundance during the 20 weeks of cultivation, suggesting a mostly stable consortium. Their CAZymes repertoire indicated that many of the most abundant species are known to deconstruct lignin (e.g., Chryseobacterium) and carry sequences related to hemicellulose and cellulose deconstruction (e.g., Chitinophaga, Niastella, Niabella, and Siphonobacter). Taken together, our results unraveled the bacterial diversity, enzymatic potential, and effectiveness of this lignocellulose-decomposing bacterial consortium. [ABSTRACT FROM AUTHOR]

This study aims to establish the relationship between ambient parameters and the diversity, composition, and function of microbial communities that predominate at each stage of the co-composting of food and agricultural waste. Culture-based and culture-independent methods were used to investigate the changes in the microbiota. The favorable conditions of high initial humidity and C/N ratio caused a decrease in the richness and biodiversity of the microbiota when such conditions existed. During the thermophilic stage, the total microbial number increased, and active mineralization of organic matter was carried out by members of the genera Bacillus, Caldibacillus, Aspergillus, and Penicillium. The fungal community was sensitive to drastic temperature changes. Byssochlamys dominated among fungi during the transition from the mesophilic to the thermophilic stage and during cooling. The biodiversity increased with time and was associated with the dynamics of germination and nitrification indices, so that the more diverse the microbial community, the higher the properties of compost that stimulate plant growth and development. The microbial community of the mature compost, together with mineral plant nutrients ready for consumption and humic compounds, make this compost a good soil additive. [ABSTRACT FROM AUTHOR]

Since periodontitis and type 2 diabetes mellitus are complex diseases, a thorough understanding of their pathogenesis requires knowing the relationship of these pathologies with other disorders and environmental factors. In this study, the representability of the subgingival periodontal microbiome of 46 subjects was studied by 16S rRNA gene sequencing and shotgun sequencing of pooled samples. We examined 15 patients with chronic periodontitis (CP), 15 patients with chronic periodontitis associated with type 2 diabetes mellitus (CPT2DM), and 16 healthy subjects (Control). The severity of generalized chronic periodontitis in both periodontitis groups of patients (CP and CPT2DM) was moderate (stage II). The male to female ratios were approximately equal in each group (22 males and 24 females); the average age of the subjects was 53.9 ± 7.3 and 54.3 ± 7.2 years, respectively. The presence of overweight patients (Body Mass Index (BMI) 30–34.9 kg/m2) and patients with class 1–2 obesity (BMI 35–45.9 kg/m2) was significantly higher in the CPT2DM group than in patients having only chronic periodontitis or in the Control group. However, there was no statistically significant difference in all clinical indices between the CP and CPT2DM groups. An analysis of the metagenomic data revealed that the alpha diversity in the CPT2DM group was increased compared to that in the CP and Control groups. The microbiome biomarkers associated with experimental groups were evaluated. In both groups of patients with periodontitis, the relative abundance of Porphyromonadaceae was increased compared to that in the Control group. The CPT2DM group was characterized by a lower relative abundance of Streptococcaceae/Pasteurellaceae and a higher abundance of Leptotrichiaceae compared to those in the CP and Control groups. Furthermore, the CP and CPT2DM groups differed in terms of the relative abundance of Veillonellaceae (which was decreased in the CPT2DM group compared to CP) and Neisseriaceae (which was increased in the CPT2DM group compared to CP). In addition, differences in bacterial content were identified by a combination of shotgun sequencing of pooled samples and genome-resolved metagenomics. The results indicate that there are subgingival microbiome-specific features in patients with chronic periodontitis associated with type 2 diabetes mellitus. [ABSTRACT FROM AUTHOR]

Cyanobacteria represent one of the most important and diverse lineages of prokaryotes with an unparalleled morphological diversity ranging from unicellular cocci and characteristic colony-formers to multicellular filamentous strains with different cell types. Sequencing of more than 1200 available reference genomes was mainly driven by their ecological relevance (Prochlorococcus, Synechococcus), toxicity (Microcystis) and the availability of axenic strains. In the current study three slowly growing non-axenic cyanobacteria with a distant phylogenetic positioning were selected for metagenome sequencing in order to (i) investigate their genomes and to (ii) uncover the diversity of associated heterotrophs. High-throughput Illumina sequencing, metagenomic assembly and binning allowed us to establish nearly complete high-quality draft genomes of all three cyanobacteria and to determine their phylogenetic position. The cyanosphere of the limnic isolates comprises up to 40 heterotrophic bacteria that likely coexisted for several decades, and it is dominated by Alphaproteobacteria and Bacteriodetes. The diagnostic marker protein RpoB ensured in combination with our novel taxonomic assessment via BLASTN-dependent text-mining a reliable classification of the metagenome assembled genomes (MAGs). The detection of one new family and more than a dozen genera of uncultivated heterotrophic bacteria illustrates that non-axenic cyanobacteria are treasure troves of hidden microbial diversity. [ABSTRACT FROM AUTHOR]

The "Saline di Tarquinia" salterns have been scarcely investigated regarding their microbiological aspects. This work studied the structure and composition of their bacterial communities along the salinity gradient (from the nearby sea through different ponds). The communities showed increasing simplification of pond bacterial diversity along the gradient (particularly if compared to those of the sea). Among the 38 assigned phyla, the most represented were Proteobacteria, Actinobacteria and Bacteroidetes. Differently to other marine salterns, where at the highest salinities Bacteroidetes dominated, preponderance of Proteobacteria was observed. At the genus level the most abundant taxa were Pontimonas, Marivita, Spiribacter, Bordetella, GpVII and Lentibacter. The α-diversity analysis showed that the communities were highly uneven, and the Canonical Correspondence Analysis indicated that they were structured by various factors (sampling site, sampling year, salinity, and sampling month). Moreover, the taxa abundance variation in relation to these significant parameters were investigated by Generalized Linear Models. This work represents the first investigation of a marine saltern, carried out by a metabarcoding approach, which permitted a broad vision of the bacterial diversity, covering both a wide temporal span (two years with monthly sampling) and the entire salinity gradient (from the nearby sea up to the crystallisation ponds). [ABSTRACT FROM AUTHOR]

The study describes sulfuric acid pretreatment of straw from Secale cereale L. (rye straw) to evaluate the effect of acid concentration and treatment time on the efficiency of biofuel production. The highest ethanol yield occurred after the enzyme treatment at a dose of 15 filter paper unit (FPU) per gram of rye straw (subjected to chemical hydrolysis with 2% sulfuric acid (SA) at 121 °C for 1 h) during 120 h. Anaerobic digestion of rye straw treated with 10% SA at 121 °C during 1 h allowed to obtain 347.42 L methane/kg volatile solids (VS). Most hydrogen was released during dark fermentation of rye straw after pretreatment of 2% SA, 121 °C, 1 h and 1% SA, 121 °C, 2 h—131.99 and 134.71 L hydrogen/kg VS, respectively. If the rye straw produced in the European Union were processed into methane, hydrogen, ethanol, the annual electricity production in 2018 could reach 9.87 TWh (terawatt-hours), 1.16 TWh, and 0.60 TWh, respectively. [ABSTRACT FROM AUTHOR]

The goal of the present work was to investigate the physicochemical and radiochemical conditions and the microbial diversity in groundwater collected near the Lake Karachai (Russia), which was formerly used for the disposal of liquid radioactive waste, to isolate the dominant bacteria, and to determine their taxonomy and the physiological characteristics responsible for their adaptation to this environment. Groundwater samples contained high concentrations of acetate, oxalate, nitrate, and sulfate, as well as radionuclides. High-throughput sequencing and analysis of the clone libraries revealed lower microbial diversity in the most strongly contaminated groundwater and a predominance of bacteria of the genera Polynucleobacter, Pusillimonas, Candidatus Pelagibacter, and of the candidate phylum Parcubacteria; these groups include species with an ultra small cell size. Archaeal sequences in the libraries belonged to ammonium oxidizers of the phylum Thaumarchaeota and methanogens of the phylum Euryarchaeota. Pure cultures of obligate and facultative ultramicrobacteria belonging to the genera Chryseobacterium, Microbacterium, Salinibacterium, Pusillimonas, Roseomonas, and Janibacter were isolated from water samples. In genomes of Pusillimonas and Roseomonas strains the genes associated with nitrate reduction, resistance to heavy metals and metalloids were revealed. Several isolates are able to participate in the geochemical process of nitrate conversion to N2 using acetate; this results in decreasing redox potential, which in turn may stimulate radionuclide reduction and decrease radionuclide migration in groundwater. [ABSTRACT FROM AUTHOR]