Geogenic contaminants pose a global threat to ensuring access to safe drinking water. Manganese (Mn) is a naturally-occurring redox-active element which in its reduced form, Mn(II), is a widespread groundwater contaminant. Prolonged consumption of water containing high levels of Mn has been linked to adverse effects on memory, attention, motor skills, and nervous system function, particularly in vulnerable groups including pregnant individuals and young children. In addition, Mn can lead to aesthetic issues such as altered taste, clogging, and damage to plumbing systems. While Mn has historically been regulated as an aesthetic concern, a mounting body of evidence linking health issues to Mn exposure through drinking water has heightened the challenges of using groundwater to meet drinking water needs. Recently, Health Canada established a health guideline which set a maximum acceptable concentration for total Mn in drinking water of 120 μg/L. Greensand (GS) filters are commonly used in conventional drinking water treatment systems for Mn(II) removal due to their cost-effectiveness and high exchange capacity. However, under certain conditions conventional GS systems may have a low Mn(II) removal efficiency (Galangashi et al. 2021) and encounter challenges related to Mn leaching (Outram et al. 2018), resulting in failure to meet health-related standards. Furthermore, GS filters typically undergo regeneration using potassium permanganate (KMnO 4 ), a mild oxidant that results in the release of additional Mn waste byproducts during the regeneration of the filter. Recent research suggests that Mn-containing materials can effectively activate peroxymonosulfate (PMS) and produce reactive oxygen species (ROS) that facilitate contaminant degradation. This study aims to investigate whether PMS may be used to improve greensand treatment systems and enhance Mn(II) removal from drinking water. Batch experiments were performed to test the Mn(II) removal efficiency across a range of PMS concentrations (0-500 μM) and GS mass (0.1-3 g). Aqueous Mn concentrations were measured over time using inductively coupled plasma optical emission spectrometry (ICP-OES). Solid-phase reaction products were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The mechanisms of Mn oxidation were identified by quenching experiments and electron paramagnetic resonance (EPR) spectroscopy. The activation of PMS by greensand significantly increased the removal efficiency of Mn(II) compared to the conventional method (e.g., 96.83(±3.77)% at PMS = 500 µM vs. 5.77(±11.1)% at PMS = 0 µM). Our results attribute the mechanism underlying increased Mn removal in our improved treatment method to advanced oxidation processes that involve free radicals (e.g., hydroxyl radical (·OH) and sulfate radical (SO 4 · - )) and non-free radical pathways, with Mn oxides as the main oxidation products. This study provides a new treatment method for more efficient Mn(II) remo
{"title":"Improving conventional household greensand treatment for efficient Mn(II) removal from drinking water","authors":"Binrui Li, Debra Hausladen","doi":"10.3897/aca.6.e111924","DOIUrl":"https://doi.org/10.3897/aca.6.e111924","url":null,"abstract":"Geogenic contaminants pose a global threat to ensuring access to safe drinking water. Manganese (Mn) is a naturally-occurring redox-active element which in its reduced form, Mn(II), is a widespread groundwater contaminant. Prolonged consumption of water containing high levels of Mn has been linked to adverse effects on memory, attention, motor skills, and nervous system function, particularly in vulnerable groups including pregnant individuals and young children. In addition, Mn can lead to aesthetic issues such as altered taste, clogging, and damage to plumbing systems. While Mn has historically been regulated as an aesthetic concern, a mounting body of evidence linking health issues to Mn exposure through drinking water has heightened the challenges of using groundwater to meet drinking water needs. Recently, Health Canada established a health guideline which set a maximum acceptable concentration for total Mn in drinking water of 120 μg/L. Greensand (GS) filters are commonly used in conventional drinking water treatment systems for Mn(II) removal due to their cost-effectiveness and high exchange capacity. However, under certain conditions conventional GS systems may have a low Mn(II) removal efficiency (Galangashi et al. 2021) and encounter challenges related to Mn leaching (Outram et al. 2018), resulting in failure to meet health-related standards. Furthermore, GS filters typically undergo regeneration using potassium permanganate (KMnO 4 ), a mild oxidant that results in the release of additional Mn waste byproducts during the regeneration of the filter. Recent research suggests that Mn-containing materials can effectively activate peroxymonosulfate (PMS) and produce reactive oxygen species (ROS) that facilitate contaminant degradation. This study aims to investigate whether PMS may be used to improve greensand treatment systems and enhance Mn(II) removal from drinking water. Batch experiments were performed to test the Mn(II) removal efficiency across a range of PMS concentrations (0-500 μM) and GS mass (0.1-3 g). Aqueous Mn concentrations were measured over time using inductively coupled plasma optical emission spectrometry (ICP-OES). Solid-phase reaction products were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The mechanisms of Mn oxidation were identified by quenching experiments and electron paramagnetic resonance (EPR) spectroscopy. The activation of PMS by greensand significantly increased the removal efficiency of Mn(II) compared to the conventional method (e.g., 96.83(±3.77)% at PMS = 500 µM vs. 5.77(±11.1)% at PMS = 0 µM). Our results attribute the mechanism underlying increased Mn removal in our improved treatment method to advanced oxidation processes that involve free radicals (e.g., hydroxyl radical (·OH) and sulfate radical (SO 4 · - )) and non-free radical pathways, with Mn oxides as the main oxidation products. This study provides a new treatment method for more efficient Mn(II) remo","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The last surface-level aqueous environments on Mars were likely sulfurous brines that formed as the climate cooled and large bodies of water receded during the transition from the wet Noachian to the dry Hesperian (4.1 – 3.0 Gya). To understand the diversity of microorganisms that could have inhabited such environments and their associated biosignatures, we turn to analogous environments on Earth. Here we investigated biofilm communities and their associated biosignatures at Gypsum Hill, (GH), a perennial cold spring system located at nearly 80°N on Axel Heiberg Island in the Canadian high Arctic. The biofilms develop during the summer months alongside the oligotrophic and sulphur rich GH brines and spread out along the flood plains formed by meltwater and spring run-off. Our objective was to link the microbial community structure of the biofilms to geochemical changes across the GH site as an analog to the micro-niches that could have formed during the recession of an ancient Martian Ocean. We collected 14 morphologically distinct biofilms over two field season and found that minor variations in chemistry between proximal sites impacted community structure. 16S amplicon sequencing revealed that biofilms closest to outflow channels were dominated by sulfur oxidizing bacteria, suggesting that primary production may be driven by chemolithoautotrophy. The community structure shifted towards more heterotrophic and phototrophic populations the further the biofilms appeared from a spring source. Microbial eukaryotes at the GH site were investigated for the first time through 18S sequencing with diatoms and photoautotrophic algae dominating all biofilms. Lastly, we linked the biofilm communities to potential biosignatures by examining lipid profiles to help guide the search and identification of potential remnants of hypothetical ancient Martian life.
火星表面最后的水环境很可能是含硫盐水，这是在湿润的诺亚纪向干燥的希斯纪(4.1 - 3.0 Gya)过渡期间，气候变冷，大量水体退去时形成的。为了了解可能生活在这种环境中的微生物的多样性及其相关的生物特征，我们转向地球上的类似环境。本文研究了石膏山(Gypsum Hill, GH)的生物膜群落及其相关生物特征。石膏山是位于加拿大高北极地区阿克塞尔海伯格岛近80°N的一个多年生冷泉系统。生物膜在夏季的几个月里沿着贫营养和富硫的GH盐水发育，并沿着由融水和春季径流形成的洪泛平原扩散。我们的目标是将生物膜的微生物群落结构与地球化学变化联系起来，作为古火星海洋衰退期间可能形成的微生态位的类比。我们在两个野外季节收集了14种形态不同的生物膜，发现近端站点之间化学成分的微小变化影响了群落结构。16S扩增子测序显示，最靠近流出通道的生物膜主要由硫氧化细菌主导，表明初级生产可能是由化化岩石自养驱动的。随着生物膜的出现，群落结构逐渐向异养型和光养型转变。通过18S测序首次对GH位点的微生物真核生物进行了研究，硅藻和光自养藻类主导了所有生物膜。最后，我们通过检查脂质谱将生物膜群落与潜在的生物特征联系起来，以帮助指导搜索和识别假设的古代火星生命的潜在残留物。
{"title":"Characterizing biofilms and their associated biosignatures in an Arctic hypersaline cold spring Mars analog","authors":"Olivia Blenner-Hassett, Ianina Altshuler, Elisse Magnuson, Lyle Whyte","doi":"10.3897/aca.6.e111363","DOIUrl":"https://doi.org/10.3897/aca.6.e111363","url":null,"abstract":"The last surface-level aqueous environments on Mars were likely sulfurous brines that formed as the climate cooled and large bodies of water receded during the transition from the wet Noachian to the dry Hesperian (4.1 – 3.0 Gya). To understand the diversity of microorganisms that could have inhabited such environments and their associated biosignatures, we turn to analogous environments on Earth. Here we investigated biofilm communities and their associated biosignatures at Gypsum Hill, (GH), a perennial cold spring system located at nearly 80°N on Axel Heiberg Island in the Canadian high Arctic. The biofilms develop during the summer months alongside the oligotrophic and sulphur rich GH brines and spread out along the flood plains formed by meltwater and spring run-off. Our objective was to link the microbial community structure of the biofilms to geochemical changes across the GH site as an analog to the micro-niches that could have formed during the recession of an ancient Martian Ocean. We collected 14 morphologically distinct biofilms over two field season and found that minor variations in chemistry between proximal sites impacted community structure. 16S amplicon sequencing revealed that biofilms closest to outflow channels were dominated by sulfur oxidizing bacteria, suggesting that primary production may be driven by chemolithoautotrophy. The community structure shifted towards more heterotrophic and phototrophic populations the further the biofilms appeared from a spring source. Microbial eukaryotes at the GH site were investigated for the first time through 18S sequencing with diatoms and photoautotrophic algae dominating all biofilms. Lastly, we linked the biofilm communities to potential biosignatures by examining lipid profiles to help guide the search and identification of potential remnants of hypothetical ancient Martian life.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Salt caverns have been used for decades as natural gas storage facilities and are now target of large-scale underground H 2 storage to secure national energy transition goals. Contrary to CH 4 , H 2 is a universal electron donor for microbial anaerobic respiration. Suitable electron acceptors are sulfate and carbonate, which dissolve from gypsum, anhydrite and lime that can make up 10 % of subsurface salt formations. Whilst sulfate reduction is inherently linked to the formation of H 2 S, microbial CO 2 reduction can generate acetate, which can be used as carbon source by diverse microorganisms. Thus, supporting other microbial side effects, such as H 2 S formation, clogging and H 2 consumption. However, microbial diversity and activity in salt caverns are selectively controlled by salt concentrations close to saturation and limited availability of organic carbon. If these conditions allow for microbial activity was investigated in our study. To circumvent long enrichment times associated with high salinity and limited nutrient availability, we used a stable isotope labelling approach combined with nano-scale secondary ion mass spectrometry analysis (SIP-nanoSIMS) to investigate H 2 -dependant microbial activity in two brine samples and compared them with that of an extremely halophilic enrichment culture (MP-32). Heavy carbonate and water ( 13 CO 2 and 2 H 2 O) served as tracers for microbial activity. Microbial H 2 consumption was additionally investigated in microcosm experiments with brine and rock salt over a period of 200 days. Setups with MP-32 served as a positive control. Subsequently, MP-32 was selected for metagenome sequencing to explore potential metabolic pathways and strategies for osmoadaptation. Analysis of the microbial community composition in brine revealed that members of the Desulfohalobiaceae, Halobacteria and Halanaerobiales were present in all caverns and their relative abundance increased during incubation with H 2 as electron donor although sulfate reduction was not observed. But incubation with H 2 resulted in an increased uptake of 13 C from 13 CO 2 in 1.6 to 3.6 % of the cells compared to incubations without H 2 . Uptake of 2 H from 2 H 2 O was detected in 20 to 30 % of the cells and was higher when H 2 was not offered as an electron donor. Similar results were obtained from the enrichment culture MP-32, which was grown in medium with reduced salinity compared to the salt cavern brine. Uptake of 13 C was 10-fold higher when incubated with H 2 and nearly all cells incorporated 2 H with and without H 2 . A total of eight metagenome-assembled genomes (MAGs) with a completion of more than 90 % could be recovered from MP-32. Two of them belonged to Desulfohalobiaceae and can be characterized as autotrophic sulfate reducers by means of the Acetyl-Coenzyme A pathway that compensate osmotic stress by synthesizing small organic molecules. Collectively, our findings provide a new approach to study microbial activity that is st
{"title":"Detection and Characterization of Active Microbial Cells in Salt Cavern Brine","authors":"Laura Schwab","doi":"10.3897/aca.6.e108637","DOIUrl":"https://doi.org/10.3897/aca.6.e108637","url":null,"abstract":"Salt caverns have been used for decades as natural gas storage facilities and are now target of large-scale underground H 2 storage to secure national energy transition goals. Contrary to CH 4 , H 2 is a universal electron donor for microbial anaerobic respiration. Suitable electron acceptors are sulfate and carbonate, which dissolve from gypsum, anhydrite and lime that can make up 10 % of subsurface salt formations. Whilst sulfate reduction is inherently linked to the formation of H 2 S, microbial CO 2 reduction can generate acetate, which can be used as carbon source by diverse microorganisms. Thus, supporting other microbial side effects, such as H 2 S formation, clogging and H 2 consumption. However, microbial diversity and activity in salt caverns are selectively controlled by salt concentrations close to saturation and limited availability of organic carbon. If these conditions allow for microbial activity was investigated in our study. To circumvent long enrichment times associated with high salinity and limited nutrient availability, we used a stable isotope labelling approach combined with nano-scale secondary ion mass spectrometry analysis (SIP-nanoSIMS) to investigate H 2 -dependant microbial activity in two brine samples and compared them with that of an extremely halophilic enrichment culture (MP-32). Heavy carbonate and water ( 13 CO 2 and 2 H 2 O) served as tracers for microbial activity. Microbial H 2 consumption was additionally investigated in microcosm experiments with brine and rock salt over a period of 200 days. Setups with MP-32 served as a positive control. Subsequently, MP-32 was selected for metagenome sequencing to explore potential metabolic pathways and strategies for osmoadaptation. Analysis of the microbial community composition in brine revealed that members of the Desulfohalobiaceae, Halobacteria and Halanaerobiales were present in all caverns and their relative abundance increased during incubation with H 2 as electron donor although sulfate reduction was not observed. But incubation with H 2 resulted in an increased uptake of 13 C from 13 CO 2 in 1.6 to 3.6 % of the cells compared to incubations without H 2 . Uptake of 2 H from 2 H 2 O was detected in 20 to 30 % of the cells and was higher when H 2 was not offered as an electron donor. Similar results were obtained from the enrichment culture MP-32, which was grown in medium with reduced salinity compared to the salt cavern brine. Uptake of 13 C was 10-fold higher when incubated with H 2 and nearly all cells incorporated 2 H with and without H 2 . A total of eight metagenome-assembled genomes (MAGs) with a completion of more than 90 % could be recovered from MP-32. Two of them belonged to Desulfohalobiaceae and can be characterized as autotrophic sulfate reducers by means of the Acetyl-Coenzyme A pathway that compensate osmotic stress by synthesizing small organic molecules. Collectively, our findings provide a new approach to study microbial activity that is st","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chao-Lung Yang, Jingzhi Liang, Hardiljeet Boparai, Jiayu Yao, Line Lomheim, Elizabeth Edwards, Brent Sleep
Sulfidated nano zerovalent iron (S-nZVI) has garnered significant attention from researchers due to its potential for effective in-situ remediation applications. Compared to bare nZVI, sulfidation process enhances its reactivity towards chlorinated volatile organic compounds (cVOCs) and improves its longevity (Nunez Garcia et al. 2021). Stabilizing the particles with a polymer, like carboxymethyl cellulose (CMC), can further improve the performance of S-nZVI by imparting higher stability, less toxicity towards microbial cells, and a potential biostimulatory effect, making CMC-S-nZVI a promising in-situ remediation technology (Nunez Garcia et al. 2021). Recently, CMC-S-nZVI has also been applied for field-scale remediation (Nunez Garcia et al. 2020;Brumovský et al. 2021). The contaminated sites usually have multiple pollutants and not all can be degraded by CMC-S-nZVI, thus, leaving some recalcitrant cVOCs untreated (Zhang et al. 2021). Biodegradation of cVOCs by dechlorinating microbial cultures may generate highly toxic intermediates like vinyl chloride (Kocur et al. 2016). However, coupling the two treatments may be able to compensate for each other’s drawbacks, resulting in higher efficiency, longer effectiveness, non-accumulation of intermediates, and degradation of a wider range of target contaminants. However, interacting effects of CMC-S-nZVI on dechlorinating microbial cultures have not been studied yet. This research investigates the potential of combining CMC-S-nZVI and a reductive dechlorinating microbial culture (KB-1) to degrade trichloroethylene (TCE) and 1,2-dichloroethane (1,2-DCA). CMC-S-nZVI was synthesized by a two-step method: (1) CMC-nZVI was first synthesized by reducing ferrous sulfate-CMC solution with dropwise addition of sodium borohydride solution with continuous mixing and (2) then sodium dithionite solution was added as a sulfidation agent to the freshly-synthesized CMC-nZVI (Nunez Garcia et al. 2020). Effects of different sulfur-iron ratios (S/Fe), iron, and CMC concentrations on TCE degradation were studied to obtain an effective CMC-S-nZVI formulation. Results showed a successful TCE removal by the CMC-S-nZVI but 1,2-DCA was not degraded. TCE degradation by CMC-S-nZVI fitted the first-order kinetic model, with the highest degradation rate constant (0.35 h -1 ) achieved at S/Fe = 0.1 with iron and CMC concentrations of 1 gL -1 and 0.4 wt%, respectively. This CMC-S-nZVI formulation was further tested to examine its interaction with KB-1 in terms of cVOCs dechlorination and microbial population responses. A four-day aged CMC-S-nZVI was also tested to study the effect of aging. Degradation pathways for TCE and 1,2-DCA were proposed, based on the formation of degradation products. For the coupled treatment, an increase in microbial abundance was observed by quantifying DNA concentrations. This demonstrated a synergistic relationship between CMC-S-nZVI and KB-1. Unlike the CMC-S-nZVI only treatment, microcosms containing
硫化纳米零价铁(S-nZVI)由于具有有效的原位修复应用潜力而引起了研究人员的极大关注。与裸nZVI相比，硫化过程增强了其对氯化挥发性有机化合物(cVOCs)的反应性，并延长了其使用寿命(Nunez Garcia et al. 2021)。用聚合物稳定颗粒，如羧甲基纤维素(CMC)，可以进一步提高S-nZVI的性能，赋予更高的稳定性，对微生物细胞的毒性更小，并具有潜在的生物刺激作用，使CMC-S-nZVI成为一种很有前途的原位修复技术(Nunez Garcia et al. 2021)。最近，CMC-S-nZVI也被应用于现场规模的修复(Nunez Garcia et al. 2020;Brumovský et al. 2021)。被污染的场地通常有多种污染物，CMC-S-nZVI并不能降解所有污染物，因此，一些顽固的cVOCs得不到处理(Zhang et al. 2021)。通过对微生物培养物进行脱氯生物降解，可能会产生氯乙烯等剧毒中间体(Kocur et al. 2016)。然而，将这两种处理结合起来可能能够弥补彼此的缺点，从而产生更高的效率，更长的有效性，不积累中间体，并降解更大范围的目标污染物。然而，CMC-S-nZVI对脱氯微生物培养物的相互作用尚未研究。本研究探讨了CMC-S-nZVI与还原性脱氯微生物培养物(KB-1)结合降解三氯乙烯(TCE)和1,2-二氯乙烷(1,2- dca)的潜力。CMC-S-nZVI的合成方法为两步法:(1)首先将硫酸亚铁- cmc溶液通过连续混合逐步加入硼氢化钠溶液还原合成CMC-nZVI;(2)然后在新合成的CMC-nZVI中加入二亚硫酸钠溶液作为硫化剂(Nunez Garcia et al. 2020)。研究了不同硫铁比(S/Fe)、铁和CMC浓度对TCE降解的影响，获得了有效的CMC-S- nzvi配方。结果表明，CMC-S-nZVI成功去除TCE，但未降解1,2- dca。CMC-S- nzvi降解TCE符合一级动力学模型，当铁和CMC浓度分别为1 gL -1和0.4 wt%时，S/Fe = 0.1时，降解速率常数最高(0.35 h -1)。我们进一步测试了CMC-S-nZVI配方，以检测其与KB-1在cVOCs脱氯和微生物种群反应方面的相互作用。我们还测试了一个4天的CMC-S-nZVI来研究衰老的影响。根据降解产物的形成，提出了TCE和1,2- dca的降解途径。对于耦合处理，通过定量DNA浓度观察到微生物丰度的增加。这表明CMC-S-nZVI和KB-1之间存在协同关系。与CMC-S-nZVI单独处理不同，含有CMC-S-nZVI和KB-1的微生物被发现能成功降解1,2- dca。与单独的KB-1处理相比，耦合处理对TCE和1,2- dca的降解速度更快，产生的氯乙烯量更少，证实了CMC-S-nZVI的生物刺激作用。在以CMC为唯一碳源和能源的KB-1处理中，TCE和1,2- dca成功脱氯。透射电镜显示CMC-S-nZVI颗粒附着在微生物上，但没有穿透细菌细胞。综上所述，CMC-S-nZVI和KB-1联合处理可以实现TCE和1,2- dca的协同非生物-生物脱氯，这表明多污染物场所可以从这种方法中受益。此外，4天龄期CMC-S-nZVI的表现与新合成的CMC-S-nZVI相似，表明这些改进剂的制备和应用具有更可行的现场尺度修复时间。
{"title":"Relationship Between Sulfidated Nano Zero Valent Iron and a Reductive Dechlorinating Microbial Culture - Synergistic or Antagonistic? ","authors":"Chao-Lung Yang, Jingzhi Liang, Hardiljeet Boparai, Jiayu Yao, Line Lomheim, Elizabeth Edwards, Brent Sleep","doi":"10.3897/aca.6.e111354","DOIUrl":"https://doi.org/10.3897/aca.6.e111354","url":null,"abstract":"Sulfidated nano zerovalent iron (S-nZVI) has garnered significant attention from researchers due to its potential for effective in-situ remediation applications. Compared to bare nZVI, sulfidation process enhances its reactivity towards chlorinated volatile organic compounds (cVOCs) and improves its longevity (Nunez Garcia et al. 2021). Stabilizing the particles with a polymer, like carboxymethyl cellulose (CMC), can further improve the performance of S-nZVI by imparting higher stability, less toxicity towards microbial cells, and a potential biostimulatory effect, making CMC-S-nZVI a promising in-situ remediation technology (Nunez Garcia et al. 2021). Recently, CMC-S-nZVI has also been applied for field-scale remediation (Nunez Garcia et al. 2020;Brumovský et al. 2021). The contaminated sites usually have multiple pollutants and not all can be degraded by CMC-S-nZVI, thus, leaving some recalcitrant cVOCs untreated (Zhang et al. 2021). Biodegradation of cVOCs by dechlorinating microbial cultures may generate highly toxic intermediates like vinyl chloride (Kocur et al. 2016). However, coupling the two treatments may be able to compensate for each other’s drawbacks, resulting in higher efficiency, longer effectiveness, non-accumulation of intermediates, and degradation of a wider range of target contaminants. However, interacting effects of CMC-S-nZVI on dechlorinating microbial cultures have not been studied yet. This research investigates the potential of combining CMC-S-nZVI and a reductive dechlorinating microbial culture (KB-1) to degrade trichloroethylene (TCE) and 1,2-dichloroethane (1,2-DCA). CMC-S-nZVI was synthesized by a two-step method: (1) CMC-nZVI was first synthesized by reducing ferrous sulfate-CMC solution with dropwise addition of sodium borohydride solution with continuous mixing and (2) then sodium dithionite solution was added as a sulfidation agent to the freshly-synthesized CMC-nZVI (Nunez Garcia et al. 2020). Effects of different sulfur-iron ratios (S/Fe), iron, and CMC concentrations on TCE degradation were studied to obtain an effective CMC-S-nZVI formulation. Results showed a successful TCE removal by the CMC-S-nZVI but 1,2-DCA was not degraded. TCE degradation by CMC-S-nZVI fitted the first-order kinetic model, with the highest degradation rate constant (0.35 h -1 ) achieved at S/Fe = 0.1 with iron and CMC concentrations of 1 gL -1 and 0.4 wt%, respectively. This CMC-S-nZVI formulation was further tested to examine its interaction with KB-1 in terms of cVOCs dechlorination and microbial population responses. A four-day aged CMC-S-nZVI was also tested to study the effect of aging. Degradation pathways for TCE and 1,2-DCA were proposed, based on the formation of degradation products. For the coupled treatment, an increase in microbial abundance was observed by quantifying DNA concentrations. This demonstrated a synergistic relationship between CMC-S-nZVI and KB-1. Unlike the CMC-S-nZVI only treatment, microcosms containing","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"709 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Baptiste Coutret, Kurt Konhauser, Marc Laflamme, Murray Gingras
The stem-group eumetazoans, also known as basal animals, have been present on Earth since the Neoproterozoic era, as evidenced by the fossil record of the Ediacaran Period (Xiao and Laflamme 2009, Butterfield 2011, Darroch et al. 2018). Previously, it was thought that Ediacaran microbial mats (also called biomats) were a key factor for early animals, providing food resources and stimulating motility and burrowing strategies into the sediment (Seilacher 1999, Meyer et al. 2014, Buatois et al. 2014, Tarhan et al. 2017, Scott et al. 2020, Coutret and Néraudeau 2022). Other research has suggested that animals living within modern microbial mats could have used the latter as a source of O 2 , and thus they were not reliant upon bottom water oxygenation (e.g., Gingras et al. (2007), Gingras et al. (2011)). This observation leads to the hypothesis that free dissolved O 2 within the microbial mats could have facilitated the evolution of primitive animals in the Ediacaran oceans (Gingras et al. 2011). This is significant because the low concentration of dissolved O 2 is often considered a significant environmental obstacle for complex animals (Lyons et al. 2014, Knoll and Sperling 2014, Boag 2018). On the other hand, it is frequently observed that microbial mats have the ability to trap and bind sediment, and in some cases, they can even induce mineral precipitation. Following the process of lithification, the once "soft" biofilms are transformed into biolaminated organosedimentary structures known as stromatolites (Konhauser 2009). Critically, the earliest biomineralized metazoans (e.g., Cloudina - Namacalathus ) are found within biostromal carbonate reefs supported by microbialites (Hofmann and Mountjoy 2001, Penny et al. 2014; also illustrated in Fig. 1A, B: Byng Formation in the Mont Robson area (BC, Canada)). Characterized as sessile and gregarious, epibenthic filter feeders, we propose that the earliest biomineralized metazoans derived advantages from stromatolitic reefs by becoming encrusted or attached to them in shallow water environments (Fig. 1A, B: white arrows). Stromatolites are regarded as fossilized relics of microbial communities and occupied various subaqueous and shallow water environments, such as tidal flats, potentially dating back as far as 3.4 billion years ago (Gehling 1999, Walter et al. 1980). However, there is a lack of study regarding the role of stromatolites in the life of early animals. Recent field investgations, led by our group, in Cooking Lake (Canada) have demonstrated that animals are burrowing into sediments and actively exploiting the microbial mats not only for food resources, but also for oxygen (Fig. 1C-E). Other extensive Ediacaran microbialites (e.g., Fig. 1F) have been discovered in recent field studies in the Byng Formation from the Jasper area (AB, Canada). Interestingly, the earliest biomineralized metazoans were described from a similar depositional environment (Fig. 1A, B: Byng Formation in the Mont Robso
茎类真生动物，也被称为基础动物，自新元古代以来就存在于地球上，埃迪卡拉纪的化石记录证明了这一点(Xiao and Laflamme 2009, Butterfield 2011, Darroch et al. 2018)。此前，人们认为Ediacaran微生物垫(也称为生物垫)是早期动物的关键因素，提供食物资源，刺激运动和向沉积物挖洞的策略(Seilacher 1999, Meyer等人2014,Buatois等人2014,Tarhan等人2017,Scott等人2020,Coutret和n raudeau 2022)。其他研究表明，生活在现代微生物垫中的动物可能将后者作为o2的来源，因此它们不依赖底层水的氧合(例如，Gingras et al. (2007)， Gingras et al.(2011))。这一观察结果导致了一种假设，即微生物席内自由溶解的o2可能促进了埃迪卡拉纪海洋中原始动物的进化(Gingras et al. 2011)。这一点很重要，因为溶解o2的低浓度通常被认为是复杂动物的重大环境障碍(Lyons et al. 2014, Knoll and Sperling 2014, Boag 2018)。另一方面，经常观察到微生物垫具有捕获和结合沉积物的能力，在某些情况下，它们甚至可以诱导矿物沉淀。在岩化过程之后，曾经“柔软”的生物膜转变为生物层状的有机沉积结构，称为叠层石(Konhauser 2009)。重要的是，最早的生物矿化后生动物(例如，Cloudina - Namacalathus)是在微生物岩支持的生物基质碳酸盐礁中发现的(Hofmann and Mountjoy 2001, Penny et al. 2014;如图1A, B所示:Mont Robson地区(BC, Canada)的Byng组)。我们认为，最早的生物矿化后生动物是无根的、群居的底栖滤食性动物，通过在浅水环境中被包裹或附着在叠层石礁上，从叠层石礁中获得了优势(图1A, B:白色箭头)。叠层石被认为是微生物群落的化石遗迹，存在于各种水下和浅水环境中，如潮滩，可能可追溯到34亿年前(Gehling 1999, Walter et al. 1980)。然而，关于叠层石在早期动物生活中的作用的研究缺乏。我们小组最近在加拿大库克湖(Cooking Lake)进行的实地调查表明，动物在沉积物中挖洞，积极利用微生物垫，不仅是为了获取食物资源，也是为了获取氧气(图1C-E)。在最近的现场研究中，在贾斯珀地区(加拿大AB)的Byng组中发现了其他广泛的埃迪卡拉纪微生物(如图1F)。有趣的是，最早的生物矿化后生动物是在类似的沉积环境中发现的(图1A, B: Mont Robson地区(BC, Canada)的Byng组)。因此，我们的目标是重新解释微生物垫在早期动物生命中的作用，通过检查:1)与化石微生物结构相关的痕量化石;2)现代“软”生物膜，通过新鲜的生物扰动产生o2;3)矿化生物构造(埃迪卡拉纪叠层石生物层和血栓状礁丘碳酸盐)。这些重新解释将使我们能够推测微生物群落的意义，如氧光合蓝藻，在早期动物进化中。
{"title":"The Crucial Relationship: Reinforcing the Role of Microbial Mats in Early Animal Life","authors":"Baptiste Coutret, Kurt Konhauser, Marc Laflamme, Murray Gingras","doi":"10.3897/aca.6.e111320","DOIUrl":"https://doi.org/10.3897/aca.6.e111320","url":null,"abstract":"The stem-group eumetazoans, also known as basal animals, have been present on Earth since the Neoproterozoic era, as evidenced by the fossil record of the Ediacaran Period (Xiao and Laflamme 2009, Butterfield 2011, Darroch et al. 2018). Previously, it was thought that Ediacaran microbial mats (also called biomats) were a key factor for early animals, providing food resources and stimulating motility and burrowing strategies into the sediment (Seilacher 1999, Meyer et al. 2014, Buatois et al. 2014, Tarhan et al. 2017, Scott et al. 2020, Coutret and Néraudeau 2022). Other research has suggested that animals living within modern microbial mats could have used the latter as a source of O 2 , and thus they were not reliant upon bottom water oxygenation (e.g., Gingras et al. (2007), Gingras et al. (2011)). This observation leads to the hypothesis that free dissolved O 2 within the microbial mats could have facilitated the evolution of primitive animals in the Ediacaran oceans (Gingras et al. 2011). This is significant because the low concentration of dissolved O 2 is often considered a significant environmental obstacle for complex animals (Lyons et al. 2014, Knoll and Sperling 2014, Boag 2018). On the other hand, it is frequently observed that microbial mats have the ability to trap and bind sediment, and in some cases, they can even induce mineral precipitation. Following the process of lithification, the once \"soft\" biofilms are transformed into biolaminated organosedimentary structures known as stromatolites (Konhauser 2009). Critically, the earliest biomineralized metazoans (e.g., Cloudina - Namacalathus ) are found within biostromal carbonate reefs supported by microbialites (Hofmann and Mountjoy 2001, Penny et al. 2014; also illustrated in Fig. 1A, B: Byng Formation in the Mont Robson area (BC, Canada)). Characterized as sessile and gregarious, epibenthic filter feeders, we propose that the earliest biomineralized metazoans derived advantages from stromatolitic reefs by becoming encrusted or attached to them in shallow water environments (Fig. 1A, B: white arrows). Stromatolites are regarded as fossilized relics of microbial communities and occupied various subaqueous and shallow water environments, such as tidal flats, potentially dating back as far as 3.4 billion years ago (Gehling 1999, Walter et al. 1980). However, there is a lack of study regarding the role of stromatolites in the life of early animals. Recent field investgations, led by our group, in Cooking Lake (Canada) have demonstrated that animals are burrowing into sediments and actively exploiting the microbial mats not only for food resources, but also for oxygen (Fig. 1C-E). Other extensive Ediacaran microbialites (e.g., Fig. 1F) have been discovered in recent field studies in the Byng Formation from the Jasper area (AB, Canada). Interestingly, the earliest biomineralized metazoans were described from a similar depositional environment (Fig. 1A, B: Byng Formation in the Mont Robso","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135885153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rainer U. Meckenstock, Isabelle Heker, Christian Seitz, Lisa Voskuhl, Wolfgang Eisenreich
The sulfate-reducing culture N47 can grow with naphthalene and has a complete tricarboxylic acid cycle (TCA) and Wood-Ljungdahl pathway (WLP) while other organisms have only either of them. Here, we wanted to elucidate why N47 has two complete pathways potentially able to oxidize acetyl-CoA. Enzyme activities were measured in cell extracts indicating a fully functional rTCA and WLP. To elucidate the carbon flux through the pathways, cells were grown with 13 C-labeled naphthalene or 13 C-bicarbonate buffer. Amino acids and fatty acids were analysed for position specific 13 C-incorporation with GC-MS, which indicated that in catabolism, acetyl-CoA from naphthalene was fully oxidized to CO 2 via the WLP. Acetyl-CoA for anabolism of amino acids, fatty acids and carbohydrates was surprisingly not coming from the substrate naphthalene but is generated de novo by CO 2 -fixation, making N47 a chemoorganoauto-trophic microorganism. This indicates that chemoorganoauto-trophy can also occur with complex substrates but probably requires a complete WLP and rTCA in anaerobic microorganisms.
{"title":"Chemo-organo-autotrophic degradation of aromatic hydrocarbons indicates a new type of bacterial metabolism","authors":"Rainer U. Meckenstock, Isabelle Heker, Christian Seitz, Lisa Voskuhl, Wolfgang Eisenreich","doi":"10.3897/aca.6.e111950","DOIUrl":"https://doi.org/10.3897/aca.6.e111950","url":null,"abstract":"The sulfate-reducing culture N47 can grow with naphthalene and has a complete tricarboxylic acid cycle (TCA) and Wood-Ljungdahl pathway (WLP) while other organisms have only either of them. Here, we wanted to elucidate why N47 has two complete pathways potentially able to oxidize acetyl-CoA. Enzyme activities were measured in cell extracts indicating a fully functional rTCA and WLP. To elucidate the carbon flux through the pathways, cells were grown with 13 C-labeled naphthalene or 13 C-bicarbonate buffer. Amino acids and fatty acids were analysed for position specific 13 C-incorporation with GC-MS, which indicated that in catabolism, acetyl-CoA from naphthalene was fully oxidized to CO 2 via the WLP. Acetyl-CoA for anabolism of amino acids, fatty acids and carbohydrates was surprisingly not coming from the substrate naphthalene but is generated de novo by CO 2 -fixation, making N47 a chemoorganoauto-trophic microorganism. This indicates that chemoorganoauto-trophy can also occur with complex substrates but probably requires a complete WLP and rTCA in anaerobic microorganisms.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135884545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Susan Pfiffner, Audrey Paterson, Tommy Phelps, Annette Engel
Tidally influenced, saltwater marsh construction projects are being completed in Louisiana to combat coastal erosion and land loss, as well as to restore critical fisheries and counteract ecosystem injuries caused by oil spills and other anthropogenic activities. Historically, metrics of success for restored marshes have been based on the amount of aboveground biomass, survival of planted vegetation, and recruitment of local endemic versus invasive species. The microbial communities responsible for cycling nutrients within restored soils are not typically evaluated. Therefore, we investigated microbial community structure, biomass, and diversity in marsh soils that had been created from nearby dredge material over the past 10 years in the Lake Hermitage, West Point a La Hache area, and compared the results to those from natural marsh soils from Bay Batiste, as determined using phospholipid fatty acid (PLFA) and gas chromatography/mass spectrometry (GC/MS) techniques and from 16S rRNA gene profiles. Soils were collected from two depths (0-2 cm and 8-10 cm) from four sampling locations along a 100-m transect that extended inland from the coastline. Soil organic carbon content and soil pH were consistently lower at restored sites compared to natural marshes. Natural marsh soil microbial diversity strongly correlated with the biomass of typical marsh plants (e.g., Spartina alterniflora , Juncus roemerianus ), whereas restored soil diversity correlated to higher Paspalum spp. (crowngrass) and Schoenoplectus pungens (common bulrush) biomass. Created soils had higher overall microbial diversity, but natural marsh soils had at least twice as much PLFA biomass than the created marshes at the shallow depth and 10X more biomass at the deeper depth. Biomass estimates ranged from below detectable levels to 6 x10 4 pmol PLFA gdw −1 , with shallower soils from all sites exhibiting higher biomass (average 10 4 pmol PLFA gdw -1 ) compared to deeper soils (average 10 3 pmol PLFA gdw -1 ). Diverse PLFA profiles were observed. Shallow soils were dominated by terminally-branched and midchain-branched saturates that are indicative of Gram-positive microorganisms and actinomycetes. The shallow soils contained polyunsaturates indicative of phototrophs. Deeper soil profiles were dominated by monounsaturates associated with Gram-negative bacteria and sulfate- and metal-reducing bacteria. These monounsaturates contained on average 7% of the total PLFA profile as cyclopropyl fatty acids, which likely indicated anaerobic processes and the presence of nutritional stress. The shallow natural marsh soils exhibited more mid-branched saturates, branched monounsaturates, and polyunsaturates, whereas the shallow created marsh soils had more terminally-branched saturates. In the deeper soils, the natural marshes exhibited more terminally-branched saturates and monounsaturates, but the created marshes contained more saturates. GC/MS analyses of dimethyl disulfide derivatizations reve
受潮汐影响，路易斯安那州正在完成咸水沼泽建设项目，以防止海岸侵蚀和土地流失，以及恢复重要的渔业和抵消石油泄漏和其他人为活动造成的生态系统损害。从历史上看，湿地恢复成功的衡量标准是基于地上生物量的数量、种植植被的存活率以及当地特有物种与入侵物种的补充。修复土壤中负责养分循环的微生物群落通常不进行评估。因此，我们研究了过去10年来在Hermitage湖、West Point a La Hache地区由附近疏通材料形成的沼泽土壤的微生物群落结构、生物量和多样性，并将结果与Bay Batiste天然沼泽土壤的结果进行了比较，使用磷脂脂肪酸(PLFA)、气相色谱/质谱(GC/MS)技术和16S rRNA基因谱进行了测定。土壤从两个深度(0-2厘米和8-10厘米)从四个采样点收集，沿100米样带从海岸线向内陆延伸。土壤有机碳含量和pH值均低于自然湿地。天然沼泽土壤微生物多样性与典型沼泽植物(如互花米草、黄菖蒲)的生物量密切相关，而恢复土壤多样性与较高的雀稗(冠草)和芦苇(芦苇)生物量相关。人造土壤的微生物多样性总体较高，但天然沼泽土壤的PLFA生物量在浅层深度至少是人造沼泽的两倍，在深层深度则是人造沼泽的10倍。生物量估计范围从低于可检测水平到6 × 104pmol PLFA gdw−1，与深层土壤(平均103pmol PLFA gdw -1)相比，所有站点的浅层土壤表现出更高的生物量(平均104pmol PLFA gdw -1)。观察到不同的PLFA谱。浅层土壤以端支和中链支饱和菌为主，表明存在革兰氏阳性微生物和放线菌。浅层土壤含有指示光养的多不饱和物。深层土壤剖面以与革兰氏阴性菌、硫酸盐和金属还原菌相关的单不饱和菌为主。这些单不饱和脂肪酸平均占PLFA总量的7%为环丙基脂肪酸，这可能表明厌氧过程和营养压力的存在。浅层天然沼泽土壤以中支饱和度、单不饱和度和多不饱和度为主，而浅层人工湿地土壤以端支饱和度为主。在较深层土壤中，天然湿地表现出更多的端支饱和物和单不饱和物，而人工湿地则表现出更多的饱和物。二甲基二硫衍生物的GC/MS分析揭示了微生物的变化，如单不饱和物的类型和结合位置，以及土壤中甲烷营养种群的存在/不存在的变化，这也反映在16S rRNA基因谱中。从这些结果来看，人造沼泽土壤的微生物群落与天然土壤群落不同，这可能不是湿地恢复的最佳结果。随着时间的推移，人们预计地上和地下的人造沼泽的微生物多样性和生物量将开始模仿自然沼泽，但持续的监测将是必要的，以了解这些联系是如何发展和影响基本的土壤过程，营养循环，以及像鱼或甲壳类动物这样的高等生物的招募和维持。
{"title":"Microbial Diversity, Biomass, and Community Structure Differences among Restored and Natural Saltwater Marshes, Louisiana","authors":"Susan Pfiffner, Audrey Paterson, Tommy Phelps, Annette Engel","doi":"10.3897/aca.6.e110263","DOIUrl":"https://doi.org/10.3897/aca.6.e110263","url":null,"abstract":"Tidally influenced, saltwater marsh construction projects are being completed in Louisiana to combat coastal erosion and land loss, as well as to restore critical fisheries and counteract ecosystem injuries caused by oil spills and other anthropogenic activities. Historically, metrics of success for restored marshes have been based on the amount of aboveground biomass, survival of planted vegetation, and recruitment of local endemic versus invasive species. The microbial communities responsible for cycling nutrients within restored soils are not typically evaluated. Therefore, we investigated microbial community structure, biomass, and diversity in marsh soils that had been created from nearby dredge material over the past 10 years in the Lake Hermitage, West Point a La Hache area, and compared the results to those from natural marsh soils from Bay Batiste, as determined using phospholipid fatty acid (PLFA) and gas chromatography/mass spectrometry (GC/MS) techniques and from 16S rRNA gene profiles. Soils were collected from two depths (0-2 cm and 8-10 cm) from four sampling locations along a 100-m transect that extended inland from the coastline. Soil organic carbon content and soil pH were consistently lower at restored sites compared to natural marshes. Natural marsh soil microbial diversity strongly correlated with the biomass of typical marsh plants (e.g., Spartina alterniflora , Juncus roemerianus ), whereas restored soil diversity correlated to higher Paspalum spp. (crowngrass) and Schoenoplectus pungens (common bulrush) biomass. Created soils had higher overall microbial diversity, but natural marsh soils had at least twice as much PLFA biomass than the created marshes at the shallow depth and 10X more biomass at the deeper depth. Biomass estimates ranged from below detectable levels to 6 x10 4 pmol PLFA gdw −1 , with shallower soils from all sites exhibiting higher biomass (average 10 4 pmol PLFA gdw -1 ) compared to deeper soils (average 10 3 pmol PLFA gdw -1 ). Diverse PLFA profiles were observed. Shallow soils were dominated by terminally-branched and midchain-branched saturates that are indicative of Gram-positive microorganisms and actinomycetes. The shallow soils contained polyunsaturates indicative of phototrophs. Deeper soil profiles were dominated by monounsaturates associated with Gram-negative bacteria and sulfate- and metal-reducing bacteria. These monounsaturates contained on average 7% of the total PLFA profile as cyclopropyl fatty acids, which likely indicated anaerobic processes and the presence of nutritional stress. The shallow natural marsh soils exhibited more mid-branched saturates, branched monounsaturates, and polyunsaturates, whereas the shallow created marsh soils had more terminally-branched saturates. In the deeper soils, the natural marshes exhibited more terminally-branched saturates and monounsaturates, but the created marshes contained more saturates. GC/MS analyses of dimethyl disulfide derivatizations reve","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"717 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135993111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amelia Danzinger, Robert Barnes, Stephen Larter, Steven Bryant, Casey Hubert
Through millions of years of evolution, bacteria have developed unique and complex ways to survive, allowing them to inhabit ecosystems all over the Earth, including places with high metal ion concentrations. Bacteria have developed many survival mechanisms to evade metal ion toxicity. Survival mechanisms to evade metal toxicity include the ability to transform metal ions into nanoparticles. When metal ions bind to other constituents to form nanoparticles, the metal ion concentrations in the environment can be lowered, in turn lessening the likelihood of cells encountering toxic concentrations of metals. These nanoparticles can be expelled by the bacteria into the environment, remain inside the bacteria, or attached to the cell surface. Bacteria and metal nanoparticles have many useful functions on their own. Furthermore, these functions can be combined when the two come together. Cells that produce metal nanoparticles that remain attached to their surface are referred to as biological-nanoparticle hybrids (bionanohybrids), as shown in the scanning electron image in Fig. 1. Surface-associated nanoparticles (SANs) can enhance biological functions, enabling a variety of new applications related to bioremediation, energy production and storage, and agricultural and medical advances. Bionanohybrid research also creates new opportunities to investigate microbial communities, synthetic biology, and the origins of life. Metal-sulfide SANs are of particular interest due to their semi-conductor abilities and examples of their generation by multiple bacterial species. This includes bacteria inhabiting metal-rich extreme environments like the Mariana Trench, to bacteria found in the human gut (such as E. coli ). While these bacteria are very different, they do share in common the cysteine desulfhydrase enzyme—which plays a crucial role in the formation of metal-sulfide bionanohybrids. Cysteine desulfhydrase converts the amino acid cysteine into sulfide that then reacts with environmental metal cations to create metal sulfide nanoparticles (Raouf Hosseini and Nasiri Sarvi 2015). Under the right conditions (e.g., optimal ratios of metal and cysteine to cell density and growth phase), the resulting nanoparticles remain attached to the surface of the cell, as shown in Fig. 1 (Barnes et al. 2022). Despite the emergence of bionanohybrid applications, very little is known about how the bionanohybrid lifestyle impacts cells. This project aims to uncover some of the fundamental questions regarding bionanohybrid gene expression by analyzing the RNA transcripts from E. coli K-12 cells with different degrees of cadmium sulfide (CdS) SAN coverage. Gene expression studies may reveal fundamental differences between bionanohybrids and uncoated bacteria, potentially informing development of industrially advantageous bacteria strains that can produce more SANs. Gel electrophoresis and/or density gradient centrifugation will be used to separate cells that are uncoated, lightl
{"title":"Gene Expression in Cadmium Sulfide Biological-Nanoparticle Hybrids","authors":"Amelia Danzinger, Robert Barnes, Stephen Larter, Steven Bryant, Casey Hubert","doi":"10.3897/aca.6.e108174","DOIUrl":"https://doi.org/10.3897/aca.6.e108174","url":null,"abstract":"Through millions of years of evolution, bacteria have developed unique and complex ways to survive, allowing them to inhabit ecosystems all over the Earth, including places with high metal ion concentrations. Bacteria have developed many survival mechanisms to evade metal ion toxicity. Survival mechanisms to evade metal toxicity include the ability to transform metal ions into nanoparticles. When metal ions bind to other constituents to form nanoparticles, the metal ion concentrations in the environment can be lowered, in turn lessening the likelihood of cells encountering toxic concentrations of metals. These nanoparticles can be expelled by the bacteria into the environment, remain inside the bacteria, or attached to the cell surface. Bacteria and metal nanoparticles have many useful functions on their own. Furthermore, these functions can be combined when the two come together. Cells that produce metal nanoparticles that remain attached to their surface are referred to as biological-nanoparticle hybrids (bionanohybrids), as shown in the scanning electron image in Fig. 1. Surface-associated nanoparticles (SANs) can enhance biological functions, enabling a variety of new applications related to bioremediation, energy production and storage, and agricultural and medical advances. Bionanohybrid research also creates new opportunities to investigate microbial communities, synthetic biology, and the origins of life. Metal-sulfide SANs are of particular interest due to their semi-conductor abilities and examples of their generation by multiple bacterial species. This includes bacteria inhabiting metal-rich extreme environments like the Mariana Trench, to bacteria found in the human gut (such as E. coli ). While these bacteria are very different, they do share in common the cysteine desulfhydrase enzyme—which plays a crucial role in the formation of metal-sulfide bionanohybrids. Cysteine desulfhydrase converts the amino acid cysteine into sulfide that then reacts with environmental metal cations to create metal sulfide nanoparticles (Raouf Hosseini and Nasiri Sarvi 2015). Under the right conditions (e.g., optimal ratios of metal and cysteine to cell density and growth phase), the resulting nanoparticles remain attached to the surface of the cell, as shown in Fig. 1 (Barnes et al. 2022). Despite the emergence of bionanohybrid applications, very little is known about how the bionanohybrid lifestyle impacts cells. This project aims to uncover some of the fundamental questions regarding bionanohybrid gene expression by analyzing the RNA transcripts from E. coli K-12 cells with different degrees of cadmium sulfide (CdS) SAN coverage. Gene expression studies may reveal fundamental differences between bionanohybrids and uncoated bacteria, potentially informing development of industrially advantageous bacteria strains that can produce more SANs. Gel electrophoresis and/or density gradient centrifugation will be used to separate cells that are uncoated, lightl","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"171 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135993639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alberta is a province that has vast deposits of natural gas. However, in its natural form it is considered sour in that it has impurities, i.e., it contains hydrogen sulphide (H 2 S), carbonyl sulfide (COS), carbon dioxide (CO 2 ), mercaptans and organic sulphides. To enable the marketing of the natural gas these impurities must be removed using organic compounds and solvents. As a result of spills, leakage during processes, seepage from unlined storage ponds some of these solvents have contaminated groundwater around natural gas processing facilities. Remediation of the organic solvents is a difficult problem. To achieve an understanding of the processes involved in their degradation, a hydrogeochemical assessment of a site can be done using existing data from the site to track the development of groundwater redox zones across the different hydrostratigraphic units (HSU). This is relevant because the oxidation is hypothesized to have contributed to the biodegradation of the compounds. The objective of this global assessment is to assign a groundwater redox zone for each sample, with special emphasis placed on defining the oxidative groundwater zone (OGZ) due to its relevance to biodegradation. Ideally, the oxic groundwater zone would be defined based on the concentration of molecular oxygen (i.e., dissolved ) in groundwater (McMahon and Chapelle 2008). However, molecular oxygen, normally measured as ‘dissolved oxygen’, was not routinely measured as a field parameter in this study and therefore was unavailable to define the OGZ. The scheme adopted considers the concentrations of terminal electron acceptors (TEA) present in groundwater and measured in commonly measured parameters including oxygen, nitrate, and sulphate and dissolved metals (manganese and iron). These TEA's are consumed under progressively more reducing conditions after oxygen reduction is complete in the order: nitrate reduction, manganese reduction, iron reduction, sulphate reduction, and finally carbonate reduction (one form of methanogenesis). The results show that redox zonation is heterogeneously distributed across the site, both within and between HSUs. Multiple lines of hydrogeochemical evidence support buffered aerobic biodegradation at the site.
{"title":"Organic Solvent Contamination in Groundwater Around Natural Gas Plants","authors":"Maurice Shevalier, Hugh Abercrombie","doi":"10.3897/aca.6.e109376","DOIUrl":"https://doi.org/10.3897/aca.6.e109376","url":null,"abstract":"Alberta is a province that has vast deposits of natural gas. However, in its natural form it is considered sour in that it has impurities, i.e., it contains hydrogen sulphide (H 2 S), carbonyl sulfide (COS), carbon dioxide (CO 2 ), mercaptans and organic sulphides. To enable the marketing of the natural gas these impurities must be removed using organic compounds and solvents. As a result of spills, leakage during processes, seepage from unlined storage ponds some of these solvents have contaminated groundwater around natural gas processing facilities. Remediation of the organic solvents is a difficult problem. To achieve an understanding of the processes involved in their degradation, a hydrogeochemical assessment of a site can be done using existing data from the site to track the development of groundwater redox zones across the different hydrostratigraphic units (HSU). This is relevant because the oxidation is hypothesized to have contributed to the biodegradation of the compounds. The objective of this global assessment is to assign a groundwater redox zone for each sample, with special emphasis placed on defining the oxidative groundwater zone (OGZ) due to its relevance to biodegradation. Ideally, the oxic groundwater zone would be defined based on the concentration of molecular oxygen (i.e., dissolved ) in groundwater (McMahon and Chapelle 2008). However, molecular oxygen, normally measured as ‘dissolved oxygen’, was not routinely measured as a field parameter in this study and therefore was unavailable to define the OGZ. The scheme adopted considers the concentrations of terminal electron acceptors (TEA) present in groundwater and measured in commonly measured parameters including oxygen, nitrate, and sulphate and dissolved metals (manganese and iron). These TEA's are consumed under progressively more reducing conditions after oxygen reduction is complete in the order: nitrate reduction, manganese reduction, iron reduction, sulphate reduction, and finally carbonate reduction (one form of methanogenesis). The results show that redox zonation is heterogeneously distributed across the site, both within and between HSUs. Multiple lines of hydrogeochemical evidence support buffered aerobic biodegradation at the site.","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135994556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Heidi Smith, Lauren Lui, Anna Zelaya, Isaac Miller, Charles Paradis, Torben Nielsen, Bradley Biggs, Benjamin Adler, Terry Hazen, Adam Arkin, Matthew Fields
Subsurface environments represent diverse microbial communities responsible for mediating biogeochemical cycles linked to the turnover of organic and inorganic carbon important to groundwater used by human society for consumption, irrigation, agriculture and industry. Within the different sediment environments, microorganisms typically reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the respective contributions of groundwater (planktonic) and sediment-associated (biofilm) cells to subsurface processes is largely unresolved. In order to directly compare the distribution of microbial biomass and activity in a shallow, subsurface environment, total cell numbers, translationally-active cell numbers (Bioorthogonal non-canonical amino acid tagging- BONCAT), and microbial activity ( 3 H-Leucine incorporation) were investigated for a low biomass pristine and contaminated groundwater and corresponding soil cores. The results demonstrated that cell numbers for the 0.2 um fraction were approximately an order of magnitude higher for the pristine groundwater compared to the contaminated groundwater (10 6 v. 10 5 ). When contaminated groundwater was compared to the pristine, there was a drastic reduction in the BONCAT activity and the contaminated groundwater was between 100-700-fold less. Additionally, the rate of leucine incorporation ( 3 H-leucine) on a per cell basis in pristine groundwater was up to 1,000 times greater than the contaminated groundwater, respectively. Overall, like total cell numbers, activity was lower (both per volume and per cell) in contaminated groundwater compared to pristine groundwater. In pristine soil, activity ( 3 H-leucine) displayed steep gradients of microbial activity in association with transition zones of water table height ( i.e ., vadose, capillary fringe, saturated). A similar trend was also observed for the contaminated soil; however, the contaminated soil displayed an overall gradient of decreasing activity with depth. The highest activity for pristine soil was 9,253 ng C/g/d located in the transition depth between the capillary fringe and the saturated zone. Conversely, the highest activity for the contaminated soil was 9,175 ng C/g/d located in the vadose zone, perhaps the zone that is least impacted by contaminant flux. The pristine groundwater had higher activity rates than pristine sediment (per cell), but the contaminated groundwater had slower activity rates than the contaminated sediment (per cell). However, for both pristine and contaminated samples on a per volume basis, sediments had the vast majority of microbial activity compared to groundwater (80-95%). In the absence of strong selection forces compared to the contaminated well, the uncontaminated samples demo
地下环境代表着不同的微生物群落，它们负责调节与有机和无机碳周转有关的生物地球化学循环，这些有机和无机碳对人类社会用于消费、灌溉、农业和工业的地下水至关重要。在不同的沉积物环境中，微生物通常生活在两个不同的阶段(浮游或生物膜)，并且在群落组成、结构和活动方面，自由生活和附着群落之间存在显著差异。然而，很大程度上由于采样限制和固体基质工作的挑战，地下水(浮游生物)和与沉积物相关的(生物膜)细胞对地下过程的各自贡献在很大程度上尚未解决。为了直接比较浅层、地下环境中微生物生物量和活性的分布，研究了低生物量原始污染地下水和相应土壤岩心的总细胞数、翻译活性细胞数(生物正交非规范氨基酸标记- BONCAT)和微生物活性(3 h -亮氨酸掺入)。结果表明，与污染地下水相比，0.2 um馏分的原始地下水的细胞数大约高出一个数量级(10.6 vs 10.5)。当被污染的地下水与原始地下水进行比较时，BONCAT活动急剧减少，受污染的地下水减少了100-700倍。此外，原始地下水中每个细胞的亮氨酸掺入率(3 h -亮氨酸)分别比污染地下水高1000倍。总的来说，与细胞总数一样，污染地下水的活性(每体积和每个细胞)比原始地下水低。在原始土壤中，微生物活性(3 h -亮氨酸)与地下水位过渡带(即渗透、毛细条纹、饱和)相关，呈现出陡峭的梯度。污染土壤也有类似的趋势;土壤活性随深度的增加呈整体递减趋势。在毛管边缘与饱和区过渡深度处，土壤活性最高，为9253 ng C/g/d。相反，污染土壤的最高活性为9,175 ng C/g/d，位于渗透区，可能是受污染物通量影响最小的区域。原始地下水的活跃率高于原始沉积物(单位细胞)，而污染地下水的活跃率低于污染沉积物(单位细胞)。然而，在单位体积的基础上，对于原始和受污染的样品，与地下水相比，沉积物具有绝大多数的微生物活性(80-95%)。与受污染的井相比，在缺乏强大的选择力的情况下，未受污染的样品在可存活种群和翻译活跃种群之间表现出更多的系统发育差异，这可能归因于生长速度的差异。受污染的地下水样品在活性部分以单一的、持久的罗丹诺杆菌菌株为主，而在翻译活性部分以红球菌、Brevundimonas和假单胞菌菌株为主。总体而言，最活跃的asv在估计的景观中普遍存在并持续存在。这是第一次在地下水和地下沉积物之间进行定量比较，以及在常用的测序方法中预测可行和活跃的asv(例如，稳定的模拟探测- SAP)。结果表明，现场采样方案应包括可行性和基于活动的评估，这可以帮助描述地下系统内外不同微生物群落中的关键微生物种群。
{"title":"Biomass distribution and activity of respective subsurface sediments and groundwater within a shallow subsurface ecosystem","authors":"Heidi Smith, Lauren Lui, Anna Zelaya, Isaac Miller, Charles Paradis, Torben Nielsen, Bradley Biggs, Benjamin Adler, Terry Hazen, Adam Arkin, Matthew Fields","doi":"10.3897/aca.6.e108389","DOIUrl":"https://doi.org/10.3897/aca.6.e108389","url":null,"abstract":"Subsurface environments represent diverse microbial communities responsible for mediating biogeochemical cycles linked to the turnover of organic and inorganic carbon important to groundwater used by human society for consumption, irrigation, agriculture and industry. Within the different sediment environments, microorganisms typically reside in two distinct phases (planktonic or biofilm), and significant differences in community composition, structure and activity between free-living and attached communities are commonly accepted. However, largely due to sampling constraints and the challenges of working with solid substrata, the respective contributions of groundwater (planktonic) and sediment-associated (biofilm) cells to subsurface processes is largely unresolved. In order to directly compare the distribution of microbial biomass and activity in a shallow, subsurface environment, total cell numbers, translationally-active cell numbers (Bioorthogonal non-canonical amino acid tagging- BONCAT), and microbial activity ( 3 H-Leucine incorporation) were investigated for a low biomass pristine and contaminated groundwater and corresponding soil cores. The results demonstrated that cell numbers for the 0.2 um fraction were approximately an order of magnitude higher for the pristine groundwater compared to the contaminated groundwater (10 6 v. 10 5 ). When contaminated groundwater was compared to the pristine, there was a drastic reduction in the BONCAT activity and the contaminated groundwater was between 100-700-fold less. Additionally, the rate of leucine incorporation ( 3 H-leucine) on a per cell basis in pristine groundwater was up to 1,000 times greater than the contaminated groundwater, respectively. Overall, like total cell numbers, activity was lower (both per volume and per cell) in contaminated groundwater compared to pristine groundwater. In pristine soil, activity ( 3 H-leucine) displayed steep gradients of microbial activity in association with transition zones of water table height ( i.e ., vadose, capillary fringe, saturated). A similar trend was also observed for the contaminated soil; however, the contaminated soil displayed an overall gradient of decreasing activity with depth. The highest activity for pristine soil was 9,253 ng C/g/d located in the transition depth between the capillary fringe and the saturated zone. Conversely, the highest activity for the contaminated soil was 9,175 ng C/g/d located in the vadose zone, perhaps the zone that is least impacted by contaminant flux. The pristine groundwater had higher activity rates than pristine sediment (per cell), but the contaminated groundwater had slower activity rates than the contaminated sediment (per cell). However, for both pristine and contaminated samples on a per volume basis, sediments had the vast majority of microbial activity compared to groundwater (80-95%). In the absence of strong selection forces compared to the contaminated well, the uncontaminated samples demo","PeriodicalId":101714,"journal":{"name":"ARPHA Conference Abstracts","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136032554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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