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1.
Water Res X ; 23: 100224, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38711798

ABSTRACT

The ongoing evolution of SARS-CoV-2 is a significant concern, especially with the decrease in clinical sequencing efforts, which impedes the ability of public health sectors to prepare for the emergence of new variants and potential COVID-19 outbreaks. Wastewater-based epidemiology (WBE) has been proposed as a surveillance program to detect and monitor the SARS-CoV-2 variants being transmitted in communities. However, research is limited in evaluating the effectiveness of wastewater collection at sentinel sites for monitoring disease prevalence and variant dynamics, especially in terms of inferring the epidemic patterns on a broader scale, such as at the state/province level. This study utilized a multiplexed tiling amplicon-based sequencing (ATOPlex) to track the longitudinal dynamics of variant of concern (VOC) in wastewater collected from municipalities in Queensland, Australia, spanning from 2020 to 2022. We demonstrated that wastewater epidemiology measured by ATOPlex exhibited a strong and consistent correlation with the number of daily confirmed cases. The VOC dynamics observed in wastewater closely aligned with the dynamic profile reported by clinical sequencing. Wastewater sequencing has the potential to provide early warning information for emerging variants. These findings suggest that WBE at sentinel sites, coupled with sensitive sequencing methods, provides a reliable and long-term disease surveillance strategy.

2.
Essays Biochem ; 67(4): 753-768, 2023 08 11.
Article in English | MEDLINE | ID: mdl-37449414

ABSTRACT

Aerobic nitrification is a key process in the global nitrogen cycle mediated by microorganisms. While nitrification has primarily been studied in near-neutral environments, this process occurs at a wide range of pH values, spanning ecosystems from acidic soils to soda lakes. Aerobic nitrification primarily occurs through the activities of ammonia-oxidising bacteria and archaea, nitrite-oxidising bacteria, and complete ammonia-oxidising (comammox) bacteria adapted to these environments. Here, we review the literature and identify knowledge gaps on the metabolic diversity, ecological distribution, and physiological adaptations of nitrifying microorganisms in acidic and alkaline environments. We emphasise that nitrifying microorganisms depend on a suite of physiological adaptations to maintain pH homeostasis, acquire energy and carbon sources, detoxify reactive nitrogen species, and generate a membrane potential at pH extremes. We also recognize the broader implications of their activities primarily in acidic environments, with a focus on agricultural productivity and nitrous oxide emissions, as well as promising applications in treating municipal wastewater.


Subject(s)
Ammonia , Nitrification , Ammonia/metabolism , Ecosystem , Oxidation-Reduction , Bacteria/metabolism
3.
Nat Microbiol ; 8(4): 581-595, 2023 04.
Article in English | MEDLINE | ID: mdl-36747116

ABSTRACT

Molecular hydrogen (H2) is an abundant and readily accessible energy source in marine systems, but it remains unknown whether marine microbial communities consume this gas. Here we use a suite of approaches to show that marine bacteria consume H2 to support growth. Genes for H2-uptake hydrogenases are prevalent in global ocean metagenomes, highly expressed in metatranscriptomes and found across eight bacterial phyla. Capacity for H2 oxidation increases with depth and decreases with oxygen concentration, suggesting that H2 is important in environments with low primary production. Biogeochemical measurements of tropical, temperate and subantarctic waters, and axenic cultures show that marine microbes consume H2 supplied at environmentally relevant concentrations, yielding enough cell-specific power to support growth in bacteria with low energy requirements. Conversely, our results indicate that oxidation of carbon monoxide (CO) primarily supports survival. Altogether, H2 is a notable energy source for marine bacteria and may influence oceanic ecology and biogeochemistry.


Subject(s)
Bacteria , Seawater , Bacteria/genetics , Seawater/microbiology , Hydrogen , Oxidation-Reduction , Oceans and Seas
5.
J Environ Manage ; 320: 115883, 2022 Oct 15.
Article in English | MEDLINE | ID: mdl-35930881

ABSTRACT

This study investigated biofilm establishment, biofilm structure, and microbial community composition of biofilms in three laboratory-scale moving bed biofilm reactors. These reactors were filled with three types of plastic carriers with varied depths of living space for microbial growth. The reactors were operated under the same influent and operational conditions. Along with the operation, the results showed that carriers with grids of 50 µm in height delayed the biofilm development and formed the thinnest biofilm and a carpet-like structure with the lowest α-diversity. In comparison, another two carriers with grids of 200 and 400 µm in height formed thick biofilms and large colonies with more voids and channels. Quantified properties of biofilm thickness, biomass, heterogeneity, portion of the biofilm exposed to the nutrient, and maximum diffusion distance were examined, and the results demonstrated that they almost (except for heterogeneity) strongly correlated to the α-diversity of microbial community. These illustrate that depth of living space, as an important parameter for carrier, could drive the formation of biofilm structure and community composition. It improves understanding of influencing factors on biofilm establishment, structure and its microbial community, and would be helpful for the design of biofilm processes.


Subject(s)
Microbiota , Nitrification , Biofilms , Biomass , Bioreactors
6.
Article in English | MEDLINE | ID: mdl-35679111

ABSTRACT

A nonmotile, facultatively anaerobic and rod-shaped bacterial strain, designated M1T was isolated from a bioreactor being operated at pH ~2 at Brisbane, Australia. Colonies appeared to be convex and white. Phylogenetic analysis of its genome revealed an affiliation with the genus Mycolicibacter and its closest species based on 16S rRNA gene analysis were Mycolicibacter algericus DSM 45454T (98.8 % similarity) and Mycolicibacter terrae CIP 104321T (98.8 %) with which strain M1T shared average nucleotide identity of 81.2 % and digital DNA-DNA hybridization similarity of 23.8 %. Strain M1T grew optimally at 0 % NaCl, at pH 6 and at between 30-33 °C. The polar lipid profile of strain M1T consisted of diphosphatidylglycerol, aminophosphoglycolipid, phosphatidylcholine, phospholipid, aminolipid, phosphoglyolipid, phosphatidylglycerol, two unidentified glycolipids and four unidentified lipids. The dominant cellular fatty acids (>10 %) were C16 : 0 and C18 : 1 ω9c and summed feature 7 (C19 : 1 ω7c and/or C19 : 1 ω6c). The DNA G+C content of strain M1T was 69.1 mol%. Based on in silico phylogenomic analysis coupled with physiological and chemotaxonomic characterizations, we classify strain M1T as representing a novel species within the genus Mycolicibacter, for which the name Mycolicibacter acidiphilus nov. is proposed. The type strain is M1T (=MCCC 1H00416T=KCTC 49392T).


Subject(s)
Fatty Acids , Phospholipids , Bacterial Typing Techniques , Base Composition , DNA, Bacterial/genetics , Fatty Acids/chemistry , Nontuberculous Mycobacteria/genetics , Phospholipids/chemistry , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , Ubiquinone/chemistry
7.
Front Microbiol ; 13: 799859, 2022.
Article in English | MEDLINE | ID: mdl-35509320

ABSTRACT

Anaerobic methanotrophic (ANME) archaea can drive anaerobic oxidation of methane (AOM) using solid iron or manganese oxides as the electron acceptors, hypothetically via direct extracellular electron transfer (EET). This study investigated the response of Candidatus "Methanoperedens nitroreducens TS" (type strain), an ANME archaeon previously characterized to perform nitrate-dependent AOM, to an Fe(III)-amended condition over a prolonged period. Simultaneous consumption of methane and production of dissolved Fe(II) were observed for more than 500 days in the presence of Ca. "M. nitroreducens TS," indicating that this archaeon can carry out Fe(III)-dependent AOM for a long period. Ca. "M. nitroreducens TS" possesses multiple multiheme c-type cytochromes (MHCs), suggesting that it may have the capability to reduce Fe(III) via EET. Intriguingly, most of these MHCs are orthologous to those identified in Candidatus "Methanoperedens ferrireducens," an Fe(III)-reducing ANME archaeon. In contrast, the population of Ca. "M. nitroreducens TS" declined and was eventually replaced by Ca. "M. ferrireducens," implying niche differentiation between these two ANME archaea in the environment.

8.
Cent Eur J Immunol ; 47(3): 218-233, 2022.
Article in English | MEDLINE | ID: mdl-36817270

ABSTRACT

Introduction: Breast cancer (BC) is associated with an inflammatory microenvironment. In BC, epidemiological evidence suggests that inflammation is associated with a poor prognosis. However, approaches to determine the extent of inflammation in the tumor microenvironment remain unclear. Material and methods: We downloaded the expression profiles and corresponding clinicopathological information of 1050 BC tissues and 59 cases of normal breast tissue from The Cancer Genome Atlas (TCGA) dataset. Similarly, data of 1050 BC tissues were downloaded from Gene Expression Omnibus (GEO) and 200 inflammation-related genes were downloaded from the MSigDB database. We developed an inflammatory risk model to reflect the immune microenvironment in BC. Results: Multivariate Cox analysis showed that the risk score was an independent predictor of overall survival (OS). Inflammatory signature was significantly associated with clinical and molecular features and could serve as an independent prognostic factor for BC patients. Furthermore, most immune cells were significantly less infiltrated in the high-risk group than in the low-risk group. There was a significant difference in survival time between the group with a high and low tumor mutational burden (TMB) score, and the survival time of the patients with a low TMB was significantly higher than that of the high-risk group. The risk scores were significantly lower in patients who responded to immunotherapy (complete response/partial response - CR/PR) than in patients who did not respond to immunotherapy (stable disease/progressive disease - SD/PD). Conclusions: We developed and validated an inflammatory risk model, which served as an independent prognostic indicator and reflected immune response intensity in the BC microenvironment.

9.
Water Res ; 200: 117211, 2021 Jul 15.
Article in English | MEDLINE | ID: mdl-34022632

ABSTRACT

Anaerobically digested (AD) sludge is widely applied to agricultural land as fertilizer. However, heavy metals in AD sludge potentially pose a significant threat to environment. This study reports a novel bioleaching approach, with no need for externally added chemicals. Sludge acidification was achieved using the protons produced from microbial oxidation of the inherent ammonium in AD sludge. An acid-tolerant microbial consortium, dominated by ammonia-oxidizing bacteria from the genus Candidatus Nitrosoglobus (i.e. relative abundance of 72.5 ± 2.3% based on 16S rRNA gene sequencing), was enriched after 120 days incubation in a laboratory sequencing batch reactor. The consortium oxidizes ammonium even at pH 2.5, at approximately 30% of its maximum rate, measured at pH 5.5. Inoculating the consortium at a solid ratio of 1:20, caused the pH of the AD sludge to decrease from 7.5 to 2.0 over five days under aerobic conditions. As a result, metals in the AD sludge were efficiently extracted into the liquid phase. In particular, two of the most abundant toxic metals, Cu and Zn, were solubilized with high efficiencies of 88 ± 4% and 96 ± 3%, respectively. Overall, the results of this study enable the economical and safe reuse of excess sludge generated during biological wastewater treatment.


Subject(s)
Metals, Heavy , Sewage , Agriculture , Fertilizers , RNA, Ribosomal, 16S/genetics
10.
Water Res ; 196: 117026, 2021 May 15.
Article in English | MEDLINE | ID: mdl-33751975

ABSTRACT

Recently, acidic (i.e. pH<5) nitrification in activated-sludge is attracting attention because it enables stable nitritation (NH4+ â†’ NO2-), and enhances sludge reduction and stabilization. However, the key acid-tolerant ammonia oxidizers involved are poorly understood. In this study, we performed stoichiometric and kinetic characterization of a new acid-tolerant ammonia-oxidizing bacterium (AOB) belonging to gamma-proteobacterium, Candidatus Nitrosoglobus. Ca. Nitrosoglobus was cultivated in activated-sludge in a laboratory membrane bioreactor over 200 days, with a relative abundance of 55.1 ± 0.5% (indicated by 16S rRNA gene amplicon sequencing) at the time of the characterization experiments. Among all known nitrifiers, Ca. Nitrosoglobus bears the highest resistance to nitrite, low pH, and free nitrous acid (FNA). These traits define Ca. Nitrosoglobus as an adversity-strategist that tends to prosper in acidic activated-sludge, where the low pH (< 5.0) and high levels of FNA (at parts per million levels) sustained and inhibited all other nitrifiers. In contrast, in the conventional pH-neutral activated-sludge process, Ca. Nitrosoglobus is less competitive with canonical AOB (e.g. Nitrosomonas) due to the relatively slow specific growth rate and low affinities to both oxygen and total ammonia. These results advance our understanding of acid-tolerant ammonia oxidizers, and support further development of the acidic activated-sludge process in which Ca. Nitrosoglobus can play a critical role.


Subject(s)
Ammonia , Nitrification , Bioreactors , Nitrites , Nitrosomonas/genetics , Oxidation-Reduction , RNA, Ribosomal, 16S/genetics , Sewage
11.
Water Res ; 194: 116962, 2021 Apr 15.
Article in English | MEDLINE | ID: mdl-33657493

ABSTRACT

Anaerobic digestion is a commonly used process for the reduction and stabilization of wasted activated sludge generated in wastewater treatment plants. However, anaerobically-digested (AD) sludge is still a problematic waste stream due to its large volume and often poor quality. In this study, two aerobic digesters were set up to treat anaerobically-digested sludge, with one digester operated in self-generated acidic condition as the experimental reactor, and one at neutral pH as the control reactor. The acidic condition in the experimental reactor was driven by an inoculated special ammonia-oxidizing bacterium, 'Candidatus Nitrosoglobus', which can tolerate low pH. As a result of ammonium oxidation by Ca. Nitrosoglobus, the pH decreased to 4.8 ± 0.2 and nitrite accumulated to and stayed at 200.0 ± 17.2 mg N L-1, from which free nitrous acid (FNA) at 8.5 ± 1.8 mg HNO2N L-1 formed in-situ. As a combined effect of low pH and high concentration of FNA, the experimental reactor reduced the total solids (TS), volatile solids (VS) and non-volatile solids (NVS) in the AD sludge by 25.2 ± 7.0%, 29.8 ± 4.3%, and 22.6 ± 5.5%, respectively. In contrast, the control reactor without Ca. Nitrosoglobus inoculation (operated at a near-neutral pH of 6.8 ± 0.3 and no FNA formation) only reduced VS in the AD sludge by 10.4 ± 4.3%, along with negligible NVS reduction. Additionally, the acidic aerobic digestion in the experimental reactor significantly stabilized AD sludge, decreasing the specific oxygen uptake rate (SOUR) to 0.5 ± 0.1 mg O2 g-1VS h-1 and the most probable number (MPN) of Faecal Coliforms to 2.4 ± 0.1 log(MPN g-1TS), both of which meet USEPA standards for Class A biosolids. In comparison, the control reactor produced biosolids at Class B level only, with an SOUR of 1.8 ± 0.2 mg O2 g-1VS h-1 and a Faecal Coliforms MPN of 3.6 ± 0.1 log(MPN g-1TS). By reducing the volume and improving the quality of the AD sludge, the acidic aerobic digestion of AD sludge enabled by Ca. Nitrosoglobus has the potential to significantly save the sludge disposal costs in wastewater treatment.


Subject(s)
Ammonia , Sewage , Anaerobiosis , Bioreactors , Digestion , Oxidation-Reduction , Waste Disposal, Fluid
12.
Environ Sci Technol ; 55(3): 2048-2056, 2021 02 02.
Article in English | MEDLINE | ID: mdl-33444018

ABSTRACT

Oxidation of ammonium to nitrite rather than nitrate, i.e., nitritation, is critical for autotrophic nitrogen removal. This study demonstrates a robust nitritation process in treating low-strength wastewater, obtained from a mixture of real mainstream sewage with sidestream anaerobic digestion liquor. This is achieved through cultivating acid-tolerant ammonia-oxidizing bacteria (AOB) in a laboratory nitrifying bioreactor at pH 4.5-5.0. It was shown that nitrite accumulation with a high NO2-/(NO2- + NO3-) ratio of 95 ± 5% was stably maintained for more than 300 days, and the obtained volumetric NH4+ removal rate (i.e., 188 ± 14 mg N L-1 d-1) was practically useful. 16S rRNA gene sequencing analyses indicated the dominance of new AOB, "Candidatus Nitrosoglobus," in the nitrifying guild (i.e., 1.90 ± 0.08% in the total community), with the disappearance of typical activated sludge nitrifying microorganisms, including Nitrosomonas, Nitrospira, and Nitrobacter. This is the first identification of Ca. Nitrosoglobus as key ammonia oxidizers in a wastewater treatment system. It was found that Ca. Nitrosoglobus can tolerate low pH (<5.0), and free nitrous acid (FNA) at levels that inhibit AOB and nitrite-oxidizing bacteria (NOB) commonly found in wastewater treatment processes. The in situ inhibition of NOB leads to accumulation of nitrite (NO2-), which along with protons (H+) also produced in ammonium oxidation generates and sustains FNA at 3.0 ± 1.4 mg HNO2-N L-1. As such, robust PN was achieved under acidic conditions, with a complete absence of NOB. Compared to previous nitritation systems, this acidic nitritation process is featured by a higher nitric oxide (NO) but a lower nitrous oxide (N2O) emission level, with the emission factors estimated at 1.57 ± 0.08 and 0.57 ± 0.03%, respectively, of influent ammonium nitrogen load.


Subject(s)
Ammonia , Nitrosomonas , Bacteria/genetics , Bioreactors , Nitrites , Nitrogen , Oxidation-Reduction , RNA, Ribosomal, 16S/genetics , Sewage
13.
Environ Sci Technol Lett ; 8(8): 683-690, 2021 Jan 10.
Article in English | MEDLINE | ID: mdl-37566375

ABSTRACT

The application of wastewater-based epidemiology (WBE) to support the global response to the COVID-19 pandemic has shown encouraging outcomes. The accurate, sensitive, and high-throughput detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in municipal wastewater is critical for WBE. Here, we present a novel approach based on multiplexed amplicon-based sequencing, namely the ATOPlex platform, for detecting SARS-CoV-2. The ATOPlex platform is capable of quantifying SARS-CoV-2 RNA at concentrations that are at least 1 order of magnitude lower than the detection limit of reverse transcription quantitative polymerase chain reaction (RT-qPCR). Robust and accurate phylogenetic placement can be done at viral concentrations 4 times lower than the detection limit of RT-qPCR. We further found that the solid fraction in wastewater harbors a considerable amount of viral RNA, highlighting the need to extract viral RNA from the solid and liquid fractions of wastewater. This study delivers a highly sensitive, phylogenetically informative, and high-throughput analytical workflow that facilitates the application of WBE.

14.
Environ Sci Technol ; 54(23): 15414-15423, 2020 12 01.
Article in English | MEDLINE | ID: mdl-33180465

ABSTRACT

Nitrite oxidation is the primary pathway that generates nitrate in engineered systems. However, little is known about the role of a novel nitrite-oxidizing bacteria (NOB) genus Candidatus Nitrotoga in activated sludge systems. To elucidate key factors that impact NOB community composition, laboratory-scale sequencing batch reactors (SBRs) were designed and operated under the same conditions as real wastewater treatment plants to achieve considerable nitrogen removal and similar community; then, different conditions including temperature (T), dissolved oxygen (DO), free nitrous acid (FNA), and free ammonia (FA) were applied. The 16S rRNA gene-based PCR and sequence analysis illustrated that Ca. Nitrotoga were abundant even at ambient temperature, thus further challenging the previous conception of them being solely cold-adapted. Ca. Nitrotoga are less competitive than Nitrospira during oxygen deficiency, indicating its lower affinity to dissolved oxygen. Ca. Nitrotoga are the dominant nitrite oxidizers under regular exposure to FNA and FA due to their relatively higher resistance than other NOB toward these two effective biocides. Therefore, this study demonstrates that Ca. Nitrotoga can play an important role in biological nitrogen removal and also highlights the need for multiple strategies for NOB suppression for the next-generation, shortcut nitrogen removal.


Subject(s)
Nitrites , Sewage , Ammonia , Bacteria , Bioreactors , Oxidation-Reduction , RNA, Ribosomal, 16S/genetics
15.
J Robot Surg ; 14(2): 317-323, 2020 Apr.
Article in English | MEDLINE | ID: mdl-31218501

ABSTRACT

To evaluate the feasibility and safety of robotic lateral cervical lymph node dissection via BABA, 260 thyroid cancer patients with suspected level II, III, IV, and Vb lymph node metastasis were selected. The lateral cervical compartment was exposed by splitting the sternocleidomastoid muscle longitudinally, and separating between the strap muscles and the anterior margin of the sternocleidomastoid muscle. The procedure was completed in 260 patients. Mean time for robotic lateral node dissection took 80 ± 21 min. The wound catheter was removed 6.3 days. Postoperative transient symptomatic hypocalcemia was observed in 51 patients, transient hoarseness in three, seroma in three, chyle leakage in two, and tracheal injury in one. 124 patients were confirmed to have lymph node metastasis on final pathological report. Average postoperative hospital stay was 6.5 days. Robotic lateral neck dissection by BABA is the acceptable operative alternative for thyroid cancer patients who wished to keep their surgical history private.


Subject(s)
Lymph Node Excision/methods , Robotic Surgical Procedures/methods , Thyroid Cancer, Papillary/surgery , Thyroid Neoplasms/surgery , Axilla , Feasibility Studies , Female , Humans , Length of Stay , Male , Neck , Safety , Treatment Outcome
16.
J Hazard Mater ; 363: 197-204, 2019 02 05.
Article in English | MEDLINE | ID: mdl-30308358

ABSTRACT

Several industrial processes produce toxic sulfide containing streams that are often scrubbed using caustic solutions. An alternative, cost effective sulfide treatment method is bioelectrochemical sulfide removal. For the first time, a haloalkaliphilic sulfide-oxidizing microbial consortium was introduced to the anodic chamber of a microbial electrolysis cell operated at alkaline pH and with 1.0 M sodium ions. Under anode potential control, the highest sulfide removal rate was 2.16 mM/day and chemical analysis supported that the electrical current generation was from the sulfide oxidation. Biotic operation produced a maximum current density of 3625 mA/m2 compared to 210 mA/m2 while under abiotic operation. Furthermore, biotic electrical production was maintained for a longer period than for abiotic operation, potentially due to the passivation of the electrode by elemental sulfur during abiotic operation. The use of microorganisms reduced the energy input in this study compared to published electrochemical sulfide removal technologies. Sulfide-oxidizing populations dominated both the planktonic and electrode-attached communities with 16S rRNA gene sequences aligning within the genera Thioalkalivibrio, Thioalkalimicrobium, and Desulfurivibrio. The dominance of the Desulfurivibrio-like population on the anode surface offered evidence for the first haloalkaliphilic bacterium able to couple electrons from sulfide oxidation to extracellular electron transfer to the anode.


Subject(s)
Bioelectric Energy Sources , Deltaproteobacteria/metabolism , Microbiota , Sulfides/metabolism , Waste Disposal, Fluid/instrumentation , Bioreactors , Ectothiorhodospiraceae/metabolism , Electrolysis , Oxidation-Reduction , RNA, Ribosomal, 16S/genetics , Sulfides/isolation & purification
17.
Front Microbiol ; 9: 2945, 2018.
Article in English | MEDLINE | ID: mdl-30568637

ABSTRACT

Mining and processing of metal sulfide ores produces waters containing metals and inorganic sulfur compounds such as tetrathionate and thiosulfate. If released untreated, these sulfur compounds can be oxidized to generate highly acidic wastewaters [termed 'acid mine drainage (AMD)'] that cause severe environmental pollution. One potential method to remediate mining wastewaters is the maturing biotechnology of 'microbial fuel cells' that offers the sustainable removal of acid generating inorganic sulfur compounds alongside producing an electrical current. Microbial fuel cells exploit the ability of bacterial cells to transfer electrons to a mineral as the terminal electron acceptor during anaerobic respiration by replacing the mineral with a solid anode. In consequence, by substituting natural minerals with electrodes, microbial fuel cells also provide an excellent platform to understand environmental microbe-mineral interactions that are fundamental to element cycling. Previously, tetrathionate degradation coupled to the generation of an electrical current has been demonstrated and here we report a metagenomic and metatranscriptomic analysis of the microbial community. Reconstruction of inorganic sulfur compound metabolism suggested the substrate tetrathionate was metabolized by the Ferroplasma-like and Acidithiobacillus-like populations via multiple pathways. Characterized Ferroplasma species do not utilize inorganic sulfur compounds, suggesting a novel Ferroplasma-like population had been selected. Oxidation of intermediate sulfide, sulfur, thiosulfate, and adenylyl-sulfate released electrons and the extracellular electron transfer to the anode was suggested to be dominated by candidate soluble electron shuttles produced by the Ferroplasma-like population. However, as the soluble electron shuttle compounds also have alternative functions within the cell, it cannot be ruled out that acidophiles use novel, uncharacterized mechanisms to mediate extracellular electron transfer. Several populations within the community were suggested to metabolize intermediate inorganic sulfur compounds by multiple pathways, which highlights the potential for mutualistic or symbiotic relationships. This study provided the genetic base for acidophilic microbial fuel cells utilized for the remediation of inorganic sulfur compounds from AMD.

18.
Front Microbiol ; 9: 2308, 2018.
Article in English | MEDLINE | ID: mdl-30323799

ABSTRACT

Thiocyanate is a toxic compound produced by the mining and metallurgy industries that needs to be remediated prior to its release into the environment. If the industry is situated at high altitudes or near the poles, economic factors require a low temperature treatment process. Microbial fuel cells are a developing technology that have the benefits of both removing such toxic compounds while recovering electrical energy. In this study, simultaneous thiocyanate degradation and electrical current generation was demonstrated and it was suggested that extracellular electron transfer to the anode occurred. Investigation of the microbial community by 16S rRNA metatranscriptome reads supported that the anode attached and planktonic anolyte consortia were dominated by a Thiobacillus-like population. Metatranscriptomic sequencing also suggested thiocyanate degradation primarily occurred via the 'cyanate' degradation pathway. The generated sulfide was metabolized via sulfite and ultimately to sulfate mediated by reverse dissimilatory sulfite reductase, APS reductase, and sulfate adenylyltransferase and the released electrons were potentially transferred to the anode via soluble electron shuttles. Finally, the ammonium from thiocyanate degradation was assimilated to glutamate as nitrogen source and carbon dioxide was fixed as carbon source. This study is one of the first to demonstrate a low temperature inorganic sulfur utilizing microbial fuel cell and the first to provide evidence for pathways of thiocyanate degradation coupled to electron transfer.

19.
Biodegradation ; 28(4): 287-301, 2017 08.
Article in English | MEDLINE | ID: mdl-28577026

ABSTRACT

Wastewaters generated during mining and processing of metal sulfide ores are often acidic (pH < 3) and can contain significant concentrations of nitrate, nitrite, and ammonium from nitrogen based explosives. In addition, wastewaters from sulfide ore treatment plants and tailings ponds typically contain large amounts of inorganic sulfur compounds, such as thiosulfate and tetrathionate. Release of these wastewaters can lead to environmental acidification as well as an increase in nutrients (eutrophication) and compounds that are potentially toxic to humans and animals. Waters from cyanidation plants for gold extraction will often conjointly include toxic, sulfur containing thiocyanate. More stringent regulatory limits on the release of mining wastes containing compounds such as inorganic sulfur compounds, nitrate, and thiocyanate, along the need to increase production from sulfide mineral mining calls for low cost techniques to remove these pollutants under ambient temperatures (approximately 8 °C). In this study, we used both aerobic and anaerobic continuous cultures to successfully couple inorganic sulfur compound (i.e. thiosulfate and thiocyanate) oxidation for the removal of nitrogenous compounds under neutral to acidic pH at the low temperatures typical for boreal climates. Furthermore, the development of the respective microbial communities was identified over time by DNA sequencing, and found to contain a consortium including populations aligning within Flavobacterium, Thiobacillus, and Comamonadaceae lineages. This is the first study to remediate mining waste waters by coupling autotrophic thiocyanate oxidation to nitrate reduction at low temperatures and acidic pH by means of an identified microbial community.


Subject(s)
Autotrophic Processes , Cold Temperature , Denitrification , Electrons , Thiocyanates/pharmacology , Thiosulfates/pharmacology , Aerobiosis , Anaerobiosis , Autotrophic Processes/drug effects , Biodegradation, Environmental/drug effects , Bioreactors/microbiology , Denitrification/drug effects , Hydrogen-Ion Concentration , Phylogeny
20.
Chin Med J (Engl) ; 129(18): 2160-6, 2016 09 20.
Article in English | MEDLINE | ID: mdl-27625085

ABSTRACT

BACKGROUND: A large proportion of the patients with papillary thyroid microcarcinoma are young women. Therefore, minimally invasive endoscopic thyroidectomy with central neck dissection (CND) emerged and showed well-accepted results with improved cosmetic outcome, accelerated healing, and comforting the patients. This study aimed to evaluate the safety and effectiveness of robotic total thyroidectomy with CND via bilateral axillo-breast approach (BABA), compared with conventional open procedure in papillary thyroid microcarcinoma. METHODS: One-hundred patients with papillary thyroid microcarcinoma from March 2014 to January 2015 in Jinan Military General Hospital of People's Liberation Army (PLA) were randomly assigned to robotic group or conventional open approach group (n = 50 in each group). The total operative time, estimated intraoperative blood loss, numbers of lymph node removed, visual analog scale (VAS), postoperative hospital stay time, complications, and numerical scoring system (NSS, used to assess cosmetic effect) were analyzed. RESULTS: The robotic total thyroidectomy with CND via BABA was successfully performed in robotic group. There were no conversion from the robotic surgeries to open or endoscopic surgery. The subclinical central lymph node metastasis rate was 35%. The mean operative time of the robotic group was longer than that of the conventional open approach group (118.8 ± 16.5 min vs. 90.7 ± 10.3 min, P < 0.05). The study showed significant differences between the two groups in terms of the VASs (2.1 ± 1.0 vs. 3.8 ± 1.2, P < 0.05) and NSS (8.9 ± 0.8 vs. 4.8 ± 1.7, P < 0.05). The differences between the two groups in the estimated intraoperative blood loss, postoperative hospital stay time, numbers of lymph node removed, postoperative thyroglobulin levels, and complications were not statistically significant (all P > 0.05). Neither iatrogenic implantation nor metastasis occurred in punctured porous channel or chest wall in both groups. Postoperative cosmetic results were very satisfactory in the robotic group. CONCLUSIONS: Robotic total thyroidectomy with CND via BABA is safe and effective for Chinese patients with papillary thyroid microcarcinoma who worry about the neck scars.


Subject(s)
Carcinoma, Papillary/surgery , Robotic Surgical Procedures/methods , Thyroid Neoplasms/surgery , Thyroidectomy/methods , Adult , Carcinoma, Papillary/blood , Female , Humans , Length of Stay , Male , Middle Aged , Neck Dissection , Operative Time , Postoperative Period , Thyroglobulin/blood , Thyroid Neoplasms/blood
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