Improvement of gold bioleaching extraction from waste telecommunication printed circuit boards using biogenic thiosulfate by Acidithiobacillus thiooxidans.

Cyanide usage in gold processing techniques has become increasingly challenging due to its toxicity and environmental impact. It is possible to develop environmentally friendly technology using thiosulfate because of its nontoxic characteristics. Thiosulfate production requires high temperatures, resulting in high greenhouse gas emissions and energy consumption. The biogenesized thiosulfate is an unstable intermediate product of Acidithiobacillus thiooxidans sulfur oxidation pathway to sulfate. A novel eco-friendly method was presented in this study to treat spent printed circuit boards (STPCBs) using biogenesized thiosulfate (Bio-Thio) obtained from Acidithiobacillus thiooxidans cultured medium. To obtain a preferable concentration of thiosulfate among other metabolites by limiting thiosulfate oxidation, optimal concentrations of inhibitor (NaN3: 3.25 mg/L) and pH adjustments (pH= 6-7) were found to be effective. Selection of the optimal conditions has led to the highest bio-production of thiosulfate (500 mg/L). The impact of STPCBs content, ammonia, ethylenediaminetetraacetic acid (EDTA), and leaching time on Cu bio-dissolution and gold bio-extraction were investigated using enriched-thiosulfate spent medium. The suitable conditions were a pulp density of 5 g/L, an ammonia concentration of 1 M, and a leaching time of 36 h, which led to the highest selective extraction of gold (65 ± 0.78%).

Biomarker-responsive engineered probiotic diagnoses, records, and ameliorates inflammatory bowel disease in mice.

Rapid advances in synthetic biology have fueled interest in engineered microorganisms that can diagnose and treat disease. However, designing bacteria that detect dynamic disease-associated biomarkers that then drive treatment remains difficult. Here, we have developed an engineered probiotic that noninvasively monitors and records inflammatory bowel disease (IBD) occurrence and progression in real time and can release treatments via a self-tunable mechanism in response to these biomarkers. These intelligent responsive bacteria for diagnosis and therapy (i-ROBOT) consists of E. coli Nissle 1917 that responds to levels of the inflammatory marker thiosulfate by activating a base-editing system to generate a heritable genomic DNA sequence as well as producing a colorimetric signal. Fluctuations in thiosulfate also drive the tunable release of the immunomodulator AvCystatin. Orally administering i-ROBOT to mice with colitis generated molecular recording signals in processed fecal and colon samples and effectively ameliorated disease. i-ROBOT provides a promising paradigm for gastrointestinal and other metabolic disorders.

Short-chain fatty acid production and phosphorous recovery from waste activated sludge via anaerobic fermentation: A comparison of in-situ and ex-situ thiosulfate-assisted Fe2+/persulfate pretreatment.

Recently, increasing attention is given on the resource and energy recovery (e.g. short-chain fatty acids (SCFAs) and phosphorus (P)) from waste active sludge (WAS) under the "Dual carbon goals". This study compared four thiosulfate-assisted Fe2+/persulfate (TAFP) pretreatments of WAS, i.e. in-situ TAFP pretreatment (R1), ex-situ TAFP pretreatment (R2), in-situ TAFP pretreatment + pH adjustment (R3) and ex-situ TAFP pretreatment + pH adjustment (R4), followed by anaerobic fermentation over 20 days for SCFA production and P recovery. The results showed that the maximal SCFA yields in R1-4 were 730.2 ± 7.0, 1017.4 ± 13.9, 860.1 ± 40.8, and 1072.0 ± 33.2 mg COD/L, respectively, significantly higher than Control (365.2 ± 17.8 mg COD/L). The findings indicated that TAFP pretreatments (particularly ex-situ TAFP pretreatment) enhanced WAS disintegration and provided more soluble organics and subsequently promoted SCFA production. The P fractionation results showed the non-apatite inorganic P increased from 11.6 ± 0.2 mg P/g TSS in Control to 11.8 ± 0.5 (R1), 12.4 ± 0.3 (R2), 13.2 ± 0.7 (R3) and 12.7 ± 0.7 mg P/g TSS (R4), suggesting TAFP pretreatments improved P bioavailability due to formation of Fe-P mineral (Fe(H2PO4)2·2H2O), which could be recycled through magnetic separators. These findings were further strengthened by the analysis of microbial community and related marker genes that fermentative bacteria containing SCFA biosynthesis genes (e.g. pyk, pdhA, accA and accB) and iron-reducing bacteria containing iron-related proteins (e.g. feoA and feoB) were enriched in R1-4 (dominant in ex-situ pretreatment systems, R2 and R4). Economic evaluation further verified ex-situ TAFP pretreatment was cost-effective and a better strategy over other operations to treat WAS for SCFA production and P recovery.

Cellular mechanisms underlying extraordinary sulfide tolerance in a crustacean holobiont from hydrothermal vents.

The shallow-water hydrothermal vent system of Kueishan Island has been described as one of the world's most acidic and sulfide-rich marine habitats. The only recorded metazoan species living in the direct vicinity of the vents is Xenograpsus testudinatus, a brachyuran crab endemic to marine sulfide-rich vent systems. Despite the toxicity of hydrogen sulfide, X. testudinatus occupies an ecological niche in a sulfide-rich habitat, with the underlying detoxification mechanism remaining unknown. Using laboratory and field-based experiments, we characterized the gills of X. testudinatus that are the major site of sulfide detoxification. Here sulfide is oxidized to thiosulfate or bound to hypotaurine to generate the less toxic thiotaurine. Biochemical and molecular analyses demonstrated that the accumulation of thiosulfate and hypotaurine is mediated by the sodium-independent sulfate anion transporter (SLC26A11) and taurine transporter (Taut), which are expressed in gill epithelia. Histological and metagenomic analyses of gill tissues demonstrated a distinct bacterial signature dominated by Epsilonproteobacteria. Our results suggest that thiotaurine synthesized in gills is used by sulfide-oxidizing endo-symbiotic bacteria, creating an effective sulfide-buffering system. This work identified physiological mechanisms involving host-microbe interactions that support life of a metazoan in one of the most extreme environments on our planet.

Mixotrophy broadens the ecological niche range of the iron oxidizer Sideroxydans sp. CL21 isolated from an iron-rich peatland.

Sideroxydans sp. CL21 is a microaerobic, acid-tolerant Fe(II)-oxidizer, isolated from the Schlöppnerbrunnen fen. Since the genome size of Sideroxydans sp. CL21 is 21% larger than that of the neutrophilic Sideroxydans lithotrophicus ES-1, we hypothesized that strain CL21 contains additional metabolic traits to thrive in the fen. The common genomic content of both strains contains homologs of the putative Fe(II) oxidation genes, mtoAB and cyc2. A large part of the accessory genome in strain CL21 contains genes linked to utilization of alternative electron donors, including NiFe uptake hydrogenases, and genes encoding lactate uptake and utilization proteins, motility and biofilm formation, transposable elements, and pH homeostasis mechanisms. Next, we incubated the strain in different combinations of electron donors and characterized the fen microbial communities. Sideroxydans spp. comprised 3.33% and 3.94% of the total relative abundance in the peatland soil and peatland water, respectively. Incubation results indicate Sideroxydans sp. CL21 uses H2 and thiosulfate, while lactate only enhances growth when combined with Fe, H2, or thiosulfate. Rates of H2 utilization were highest in combination with other substrates. Thus, Sideroxydans sp. CL21 is a mixotroph, growing best by simultaneously using substrate combinations, which helps to thrive in dynamic and complex habitats.

A metabolic puzzle: Consumption of C1 compounds and thiosulfate in Hyphomicrobium denitrificans XT.

Many obligately heterotrophic methylotrophs oxidize thiosulfate as an additional electron source during growth on C1 compounds. Although two different pathways of thiosulfate oxidation are implemented in Hyphomicrobium denitrificans XT, a pronounced negative effect on growth rate is observed when it is cultured in the simultaneous presence of methanol and thiosulfate. In this model organism, periplasmic thiosulfate dehydrogenase TsdA catalyzes formation of the dead-end product tetrathionate. By reverse genetics we verified the second pathway that also starts in the periplasm where SoxXA catalyzes the oxidative fusion of thiosulfate to SoxYZ, from which sulfate is released by SoxB. Sulfane sulfur is then further oxidized in the cytoplasm by the sulfur-oxidizing heterodisulfide reductase-like system (sHdr) which is produced constitutively in a strain lacking the transcriptional repressor sHdrR. When exposed to thiosulfate, the ΔshdrR strain exhibited a strongly reduced growth rate even without thiosulfate in the pre-cultures. When grown on methanol, cells exhibit significantly increased NAD+/NADH ratios in the presence of thiosulfate. In contrast, thiosulfate did not exert any negative effect on growth rate or increase NAD+ levels during growth on formate. On both C1 substrates, excretion of up to 0.5 mM sulfite as an intermediate of thiosulfate (2 mM) oxidation was recorded. Sulfite is known to form adducts with pyrroloquinoline quinone, the cofactor of periplasmic methanol dehydrogenase. We rationalize that this causes specific inhibition of methanol degradation in the presence of thiosulfate while formate metabolism in the cytoplasm remains unaffected.

Dual-key-and-lock AIE probe for thiosulfate and Ag+ detection in mitochondria.

Ag+ ion detection has attracted much attention due to its important role in chemical and biological processes, as well as its potential threat to the environment and human health. Herein, we firstly constructed a dual-key-and-lock sensing strategy for Ag+ detection based on three-component co-assembly. An aggregation-induced emission luminogen (AIEgen), namely triphenylamine-thiophene-pyridinium (abbreviated to TPA-T-Py), showed unique co-assembly capability with Ag+ and S2O32- in PBS buffer (pH 7.4, 0.01 M). Cell imaging further proved that mitochondria can be lit up by TPA-T-Py under the dual key stimulation, which was successfully used for Ag+ and S2O32- detection in vitro. In brief, we provide a promising strategy for the construction of dual-lock imaging agents with organelle-targeting ability.

Disproportionation of Inorganic Sulfur Compounds by Mesophilic Chemolithoautotrophic Campylobacterota.

The disproportionation of inorganic sulfur compounds could be widespread in natural habitats, and microorganisms could produce energy to support primary productivity through this catabolism. However, the microorganisms that carry this process out and the catabolic pathways at work remain relatively unstudied. Here, we investigated the bacterial diversity involved in sulfur disproportionation in hydrothermal plumes from Carlsberg Ridge in the northwestern Indian Ocean by enrichment cultures. A bacterial community analysis revealed that bacteria of the genera Sulfurimonas and Sulfurovum, belonging to the phylum Campylobacterota and previously having been characterized as chemolithoautotrophic sulfur oxidizers, were the most dominant members in six enrichment cultures. Subsequent bacterial isolation and physiological studies confirmed that five Sulfurimonas and Sulfurovum isolates could disproportionate thiosulfate and elemental sulfur. The ability to disproportionate sulfur was also demonstrated in several strains of Sulfurimonas and Sulfurovum that were isolated from hydrothermal vents or other natural environments. Dialysis membrane experiments showed that S0 disproportionation did not require the direct contact of cells with bulk sulfur. A comparative genomic analysis showed that Campylobacterota strains did not contain some genes of the Dsr and rDSR pathways (aprAB, dsrAB, dsrC, dsrMKJOP, and qmoABC) that are involved in sulfur disproportionation in some other taxa, suggesting the existence of an unrevealed catabolic pathway for sulfur disproportionation. These findings provide evidence for the catabolic versatility of these Campylobacterota genera, which are widely distributed in chemosynthetic environments, and expand our knowledge of the microbial taxa involved in this reaction of the biogeochemical sulfur cycle in hydrothermal vent environments. IMPORTANCE The phylum Campylobacterota, notably represented by the genera Sulfurimonas and Sulfurovum, is ubiquitous and predominant in deep-sea hydrothermal systems. It is well-known to be the major chemolithoautotrophic sulfur-oxidizing group in these habitats. Herein, we show that the mesophilic predominant chemolithoautotrophs of the genera Sulfurimonas and Sulfurovum could grow via sulfur disproportionation to gain energy. This is the first report of the chemolithoautotrophic disproportionation of thiosulfate and elemental sulfur within the genera Sulfurimonas and Sulfurovum, and this comes in addition to their already known role in the chemolithoautotrophic oxidation of sulfur compounds. Sulfur disproportionation via chemolithoautotrophic Campylobacterota may represent a previously unrecognized primary production process in hydrothermal vent ecosystems.

Nitrosophilus kaiyonis sp. nov., a hydrogen-, sulfur- and thiosulfate-oxidizing chemolithoautotroph within "Campylobacteria" isolated from a deep-sea hydrothermal vent in the Mid-Okinawa Trough.

A novel bacterium, strain MOT50T, was isolated from the chimney structure at the Iheya North field in the Mid-Okinawa Trough. The cells were motile short rods with a single polar flagellum. Growth was observed between 40 and 65 â„ƒ (optimum, 52 â„ƒ), at pH values between 5.0 and 7.1 (optimum, pH 6.1) and in the presence of 2.0-4.0% NaCl (optimum, 2.5%). The isolates utilized molecular hydrogen, thiosulfate, or elemental sulfur as the sole electron donor. Thiosulfate, elemental sulfur, nitrate, and molecular oxygen are utilized as the sole electron acceptor. Ammonium is required as a nitrogen source. Thiosulfate, elemental sulfur, sulfate, or sulfite serves as a sulfur source for growth. The G + C content of the genomic DNA was 28.9%. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain MOT50T belonged to the genus Nitrosophilus of the class "Campylobacteria", and its closest relative was Nitrosophilus labii HRV44T (97.20%). On the basis of the phylogenetic, physiological, and molecular characteristics, it is proposed that the organism represents a novel species within the genus Nitrosophilus, Nitrosophilus kaiyonis sp. nov. The type strain is MOT50T (= JCM 39187T = KCTC 25251T).

Limnobacter parvus sp. nov., a Thiosulfate-Oxidizing Bacterium Isolated from Lake Water.

A novel bacterium, designated as strain YS8-69T, was isolated from an inland closed lake, Xinjiang Uygur Autonomous Region, PR China. Comparative analysis of the 16S rRNA gene sequence shows the strain was affiliated to the genus Limnobacter, in the family Burkholderiaceae, with the highest similarities to Limnobacter alexandrii LZ-4T (98.93%), Limnobacter thiooxidans DSM 13612T (98.55%), Limnobacter humi NBRC 111650T (97.66%), and Limnobacter litoralis KP1-19T (97.04%). Strain YS8-69T was a Gram stain-negative, strictly aerobic, rod shaped, catalase- and oxidase-positive bacterium, and growth was observed at 4-40 °C (optimum, 25 °C), pH 7.0-10.0 (optimum, pH 7.0), and 0-3% (w/v) NaCl (optimum, 0.5%). The principal fatty acids were C16:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c). The sole respiratory quinone was Q-8 and total polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), an unidentified aminolipid (AL), two unidentified glycolipids (GL1,2), an unidentified amino phosphoglycolipid (APGL), two unidentified phospholipids (PL1,2), two unidentified aminophospholipids (APL1,2), and three unidentified lipids (L1,2,3). The average nucleotide identity (ANI) values and in silico DDH between strain YS8-69T and L. alexandrii LZ-4T, L. thiooxidans JCM 13612T, and L. humi DSM 111650T were 73.0-80.6% and 15.8-50.2%, respectively. The genome sequence showed a length of 3,162,663 bp, with 20 contigs and 51.7% of G + C content. Based on physiological, chemotaxonomic, genotypic characteristics, and phylogenetic results, we propose that strain YS8-69T represents a novel specie of the genus Limnobacter, for which the name Limnobacter parvus sp. nov. is proposed (type strain YS8-69T = MCCC 1K08015T = KCTC 92278T).

Real-time bioelectronic sensing of environmental contaminants.

Real-time chemical sensing is crucial for applications in environmental and health monitoring1. Biosensors can detect a variety of molecules through genetic circuits that use these chemicals to trigger the synthesis of a coloured protein, thereby producing an optical signal2-4. However, the process of protein expression limits the speed of this sensing to approximately half an hour, and optical signals are often difficult to detect in situ5-8. Here we combine synthetic biology and materials engineering to develop biosensors that produce electrical readouts and have detection times of minutes. We programmed Escherichia coli to produce an electrical current in response to specific chemicals using a modular, eight-component, synthetic electron transport chain. As designed, this strain produced current following exposure to thiosulfate, an anion that causes microbial blooms, within 2 min. This amperometric sensor was then modified to detect an endocrine disruptor. The incorporation of a protein switch into the synthetic pathway and encapsulation of the bacteria with conductive nanomaterials enabled the detection of the endocrine disruptor in urban waterway samples within 3 min. Our results provide design rules to sense various chemicals with mass-transport-limited detection times and a new platform for miniature, low-power bioelectronic sensors that safeguard ecological and human health.

Moorella sulfitireducens sp. nov., a thermophilic anaerobic bacterium isolated from a terrestrial thermal spring.

In hydrothermal ecosystems, the dissolution of sulfur dioxide in water results in the formation of sulfite, which can be used in microbial metabolism. A limited number of thermophiles have been isolated using sulfite as an electron acceptor. From a terrestrial thermal spring, Sakhalin Island, Russia, we isolated a thermophilic anaerobic bacterium (strain SLA38T). Cells of strain SLA38T were spore-forming straight rods. Growth was observed at temperatures 45-65 °C (optimum at 60 °C) and pH 5.5-9.0 (optimum at pH 6.5-7.0). The novel isolate was capable of anaerobic respiration with sulfite, thiosulfate, fumarate and perchlorate or fermentative growth. Strain SLA38T utilized glycerol, lactate, pyruvate and yeast extract. It grew lithoautotrophically on carbon monoxide with thiosulfate as electron acceptor, producing acetate. The genome size of the isolate was 2.9 Mbp and genomic DNA G + C content was 53.6 mol%. Analysis of the 16S rRNA gene sequences revealed that strain SLA38T belongs to the genus Moorella. Based on the physiological features and phylogenetic analysis, we propose to assign strain SLA38T to a new species of the genus Moorella, as Moorella sulfitireducens sp. nov. The type strain is SLA38T (= DSM 111068T = VKM B-3584T).

Naphthoquinones Oxidize H2S to Polysulfides and Thiosulfate, Implications for Therapeutic Applications.

1,4-Napththoquinones (NQs) are clinically relevant therapeutics that affect cell function through production of reactive oxygen species (ROS) and formation of adducts with regulatory protein thiols. Reactive sulfur species (RSS) are chemically and biologically similar to ROS and here we examine RSS production by NQ oxidation of hydrogen sulfide (H2S) using RSS-specific fluorophores, liquid chromatography-mass spectrometry, UV-Vis absorption spectrometry, oxygen-sensitive optodes, thiosulfate-specific nanoparticles, HPLC-monobromobimane derivatization, and ion chromatographic assays. We show that NQs, catalytically oxidize H2S to per- and polysulfides (H2Sn, n = 2-6), thiosulfate, sulfite and sulfate in reactions that consume oxygen and are accelerated by superoxide dismutase (SOD) and inhibited by catalase. The approximate efficacy of NQs (in decreasing order) is, 1,4-NQ ≈ juglone ≈ plumbagin > 2-methoxy-1,4-NQ ≈ menadione >> phylloquinone ≈ anthraquinone ≈ menaquinone ≈ lawsone. We propose that the most probable reactions are an initial two-electron oxidation of H2S to S0 and reduction of NQ to NQH2. S0 may react with H2S or elongate H2Sn in variety of reactions. Reoxidation of NQH2 likely involves a semiquinone radical (NQ·-) intermediate via several mechanisms involving oxygen and comproportionation to produce NQ and superoxide. Dismutation of the latter forms hydrogen peroxide which then further oxidizes RSS to sulfoxides. These findings provide the chemical background for novel sulfur-based approaches to naphthoquinone-directed therapies.

Simultaneous nitrate and phosphate removal based on thiosulfate-driven autotrophic denitrification biofilter filled with volcanic rock and sponge iron.

This study constructed two thiosulfate-driven autotrophic denitrification biofilters filled with volcanic rock (VR-BF), sponge iron and volcanic rock (SIVR-BF), respectively. The nitrate removal load (3200 g/m3/d) and efficiency (98 %) of SIVR-BF were higher than those of VR-BF. The removal of phosphate in SIVR-BF was mainly through forming FePO4 and Fe3(PO4)2(OH)2. Sulfur and iron cycles in SIVR-BF contributed to Fe (II)/Fe (III) electron shuttle, as well as S2-, S0, Sn2- electron buffer and energy storage, which improved nitrate removal and electron utilization. The formation of multi-path collaborative denitrification dominated by sulfur autotrophic denitrification (64.2 âˆ¼ 89.6 %) in SIVR-BF. The other denitrification pathways, such as iron autotrophic denitrification, which buffered pH and reduced sulfate production. Thiobacillus (38.6 %) and Ferritrophicum (25.3 %) were the dominant genus of VR-BF and SIVR-BF, respectively, which played crucial roles in autotrophic denitrification of iron and sulfur. SIVR-BF was a promising process to realize iron-sulfur coupling autotrophic denitrification and phosphate removal.

One-pot synthesis of efficient multifunctional nitrogen-doped carbon dots with efficient yellow fluorescence emission for detection of hypochlorite and thiosulfate.

CD-based ratiometric fluorescence probes are of great significance for visual detection, but accomplishing this goal is still a particularly challenging task. Herein, nitrogen-doped carbon dots (NCDs) with bright yellow fluorescence were easily manufactured via a one-pot hydrothermal method for visual detection of hypochlorite (ClO-) and thiosulfate (S2O32-) under UV light irradiation. The as-prepared NCDs demonstrate favorable water solubility, excellent biocompatibility, superior optical properties and low cytotoxicity. Strikingly, the fluorescence of the NCDs could be quenched with ClO-. Based on these results, an original fluorescent nanoprobe was constructed for the highly discriminating recognition of ClO- by oxidation of the amino groups on their surface to nitro groups. The assay covered the ranges from 0.067 to 19.33 µM and 24 to 98 µM with a limit of detection (S/N = 3) of as low as 0.013 µM. Remarkably, a growing peak appears at 537 nm and the emission at 492 nm shrinks with the introduction of S2O32-, which demonstrates ratiometric fluorescence emission characteristics (F537nm/F492nm) in the range of 6.6-100 µM with a limit of detection (S/N = 3) of as low as 0.78 µM. In addition, the fluorescence color of the NCDs also changes (yellow-green-blue) after adding various ClO- concentrations. The fluorescence color of the NCDs-ClO- also changes (blue-green-yellow) after adding various S2O32- concentrations. This excellent ratiometric fluorescence probe was successfully further used for nuclear imaging. Accordingly, an easy-to-prepare paper-based sensor to identify ClO- and S2O32- was fabricated, which demonstrated their adaptability for in situ on-site testing. This research further opens up new opportunities for the development of efficient yellow fluorescent probes based on NCDs nanomaterials for visual detection, biomarking, and biomedical optical imaging.

Coulometer from a Digitally Controlled Galvanostat with Photometric Endpoint Detection.

In this work, a coulometer was developed from a digitally controlled galvanostat. A simple colorimeter based on a RGB LED was used as a light emitter coupled to light detectors, while light dependent resistance (LDR) and photodiodes have been developed as endpoint detectors. Both hardware and software have been adapted from the original galvanostat design. Regarding the hardware, new electrical signal conditioners (filters and voltage dividers) were included to optimize the working system. The software was developed based on an open source Arduino UNO microcontroller. The different variables that control the titration process are managed by an add-in module for Excel data acquisition software that is freely available. A study of the possible variables that influence the titration process has been carried out. The system was tested with two classical coulometric titrations such as iodometry (thiosulfate, ascorbic acid) and acid/base (potassium acid phthalate as standard). The developed system is versatile as different endpoint color indicators can be employed (starch and phenolphthalein for the investigated reactions). Different experimental arrangements have been studied: the nature of the electrodes (Pt, Ag), type of cells (two separate compartments or a single compartment), and light detectors (LDR, photodiode). The influence of several experimental parameters (both electrical, light, and integration time) was studied and chosen to obtain the best performance of the complete system. Reproducibility results below 1% can be obtained under controlled conditions. In the case of acid/base titrations, the presence of atmospheric carbon dioxide was detected, whose interference was mainly affected by the stirring rate and the titration time.

Sulfurimonas marina sp. nov., an obligately chemolithoautotrophic, sulphur-oxidizing bacterium isolated from a deep-sea sediment sample from the South China Sea.

A novel marine bacterium, designated strain B2T, was isolated from a deep-sea sediment sample collected from the South China Sea. Cells were observed to be Gram-stain negative, motile and rod shaped with a single polar flagellum. B2T could grow at 10-45 °C (optimum, 35 °C), pH 4.5-9.0 (optimum, pH 7.0) and in the presence of 1.0-8.0 % (w/v) NaCl (optimum, 3.0%). The isolate grew chemolithoautotrophically with sulphide, elemental sulphur and thiosulphate as electron donors, carbon dioxide as the sole carbon source, and molecular oxygen as the sole electron acceptor. Molecular hydrogen did not support growth. The predominant fatty acids of B2T were C16 : 1ω7c, C16 : 0 and C18 : 1ω7c. The results of phylogenetic analysis based on 16S rRNA gene sequence indicated that B2T represented a member of the genus Sulfurimonas, with the highest similarity to the 16S rRNA gene sequences of Sulfurimonas indica NW8NT (95.9 %), Sulfurimonas crateris SN118T (95.7 %), Sulfurimonas xiamenensis 1-1NT (95.6 %) and Sulfurimonas paralvinellae GO25T (95.4 %). Sequence similarities to other members of the genus Sulfurimonas were less than 95.0 %. In addition, the average nucleotide identity (ANI) value and digital DNA-DNA hybridization (dDDH) estimate between B2T and S. indica NW8NT were 73.0 and 23.7 %, respectively. The size of the complete genome of B2T is 22 61 034 bp, with a DNA G+C content of 36.0 mol %. On the basis of the phenotypic, phylogenetic and genomic data presented here, strain B2T represent a novel species of the genus Sulfurimonas, for which the name Sulfurimonas marina sp. nov. is proposed, with the type strain B2T (=MCCC 1A14515T=KCTC 15852T).

Comparative Genome Analysis of a Novel Alkaliphilic Actinobacterial Species Nesterenkonia haasae.

In the present study, a comparative genome analysis of the novel alkaliphilic actinobacterial Nesterenkonia haasae with other members of the genus Nesterenkonia was performed. The genome size of Nesterenkonia members ranged from 2,188,008 to 3,676,111 bp. N. haasae and Nesterenkonia members of the present study encode the essential glycolysis and pentose phosphate pathway genes. In addition, some Nesterenkonia members encode the crucial genes for Entner-Doudoroff pathways. Some Nesterenkonia members possess the genes responsible for sulfate/thiosulfate transport system permease protein/ ATP-binding protein and conversion of sulfate to sulfite. Nesterenkonia members also encode the genes for assimilatory nitrate reduction, nitrite reductase, and the urea cycle. All Nesterenkonia members have the genes to overcome environmental stress and produce secondary metabolites. The present study helps to understand N. haasae and Nesterenkonia members' environmental adaptation and niches specificity based on their specific metabolic properties. Further, based on genome analysis, we propose reclassifying Nesterenkonia jeotgali as a later heterotypic synonym of Nesterenkonia sandarakina.

Progress in bioleaching: fundamentals and mechanisms of microbial metal sulfide oxidation - part A.

Bioleaching of metal sulfides is performed by diverse microorganisms. The dissolution of metal sulfides occurs via two chemical pathways, either the thiosulfate or the polysulfide pathway. These are determined by the metal sulfides' mineralogy and their acid solubility. The microbial cell enables metal sulfide dissolution via oxidation of iron(II) ions and inorganic sulfur compounds. Thereby, the metal sulfide attacking agents iron(III) ions and protons are generated. Cells are active either in a planktonic state or attached to the mineral surface, forming biofilms. This review, as an update of the previous one (Vera et al., 2013a), summarizes some recent discoveries relevant to bioleaching microorganisms, contributing to a better understanding of their lifestyle. These comprise phylogeny, chemical pathways, surface science, biochemistry of iron and sulfur metabolism, anaerobic metabolism, cell-cell communication, molecular biology, and biofilm lifestyle. Recent advances from genetic engineering applied to bioleaching microorganisms will allow in the future to better understand important aspects of their physiology, as well as to open new possibilities for synthetic biology applications of leaching microbial consortia. KEY POINTS: • Leaching of metal sulfides is strongly enhanced by microorganisms • Biofilm formation and extracellular polymer production influences bioleaching • Cell interactions in mixed bioleaching cultures are key for process optimization.

Novel Type of Tetranitrosyl Iron Salt: Synthesis, Structure and Antibacterial Activity of Complex [FeL'2(NO)2][FeL'L"(NO)2] with L'-thiobenzamide and L"-thiosulfate.

In this work a new donor of nitric oxide (NO) with antibacterial properties, namely nitrosyl iron complex of [Fe(C6H5C-SNH2)2(NO)2][Fe(C6H5C-SNH2)(S2O3)(NO)2] composition (complex I), has been synthesized and studied. Complex I was produced by the reduction of the aqueous solution of [Fe2(S2O3)2(NO)2]2- dianion by the thiosulfate, with the further treatment of the mixture by the acidified alcohol solution of thiobenzamide. Based on the structural study of I (X-ray analysis, quantum chemical calculations by NBO and QTAIM methods in the frame of DFT), the data were obtained on the presence of the NO…NO interactions, which stabilize the DNIC dimer in the solid phase. The conformation properties, electronic structure and free energies of complex I hydration were studied using B3LYP functional and the set of 6-31 + G(d,p) basis functions. The effect of an aquatic surrounding was taken into account in the frame of a polarized continuous model (PCM). The NO-donating activity of complex I was studied by the amperometry method using an "amiNO-700" sensor electrode of the "inNO Nitric Oxide Measuring System". The antibacterial activity of I was studied on gram-negative (Escherichia coli) and gram-positive (Micrococcus luteus) bacteria. Cytotoxicity was studied using Vero cells. Complex I was found to exhibit antibacterial activity comparable to that of antibiotics, and moderate toxicity to Vero cells.