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Frontiers in Microbiology 2023Metal(loid) salts were used to treat infectious diseases in the past due to their exceptional biocidal properties at low concentrations. However, the mechanism of their...
Metal(loid) salts were used to treat infectious diseases in the past due to their exceptional biocidal properties at low concentrations. However, the mechanism of their toxicity has yet to be fully elucidated. The production of reactive oxygen species (ROS) has been linked to the toxicity of soft metal(loid)s such as Ag(I), Au(III), As(III), Cd(II), Hg(II), and Te(IV). Nevertheless, few reports have described the direct, or ROS-independent, effects of some of these soft-metal(loid)s on bacteria, including the dismantling of iron-sulfur clusters [4Fe-4S] and the accumulation of porphyrin IX. Here, we used genome-wide genetic, proteomic, and biochemical approaches under anaerobic conditions to evaluate the direct mechanisms of toxicity of these metal(loid)s in . We found that certain soft-metal(loid)s promote protein aggregation in a ROS-independent manner. This aggregation occurs during translation in the presence of Ag(I), Au(III), Hg(II), or Te(IV) and post-translationally in cells exposed to Cd(II) or As(III). We determined that aggregated proteins were involved in several essential biological processes that could lead to cell death. For instance, several enzymes involved in amino acid biosynthesis were aggregated after soft-metal(loid) exposure, disrupting intracellular amino acid concentration. We also propose a possible mechanism to explain how soft-metal(loid)s act as proteotoxic agents.
PubMed: 38075883
DOI: 10.3389/fmicb.2023.1281058 -
Environmental Science and Pollution... Apr 2024This manuscript presents a scientometric review of recent advances in microwave pretreatment processes for sewage sludge, systematically identifying existing gaps and... (Review)
Review
This manuscript presents a scientometric review of recent advances in microwave pretreatment processes for sewage sludge, systematically identifying existing gaps and prospects. For this purpose, 1763 papers on the application of microwave technology to sludge pretreatment were retrieved from the Web of Science (WoS) using relevant keywords. These publications were then analyzed using diverse scientometric indices. The results show that research in this field encompasses applications based on the non-thermal effects of microwaves, enhanced effectiveness of anaerobic digestion (AD), and the energy balance of this pretreatment system. Overcoming existing technical challenges, such as the cleavage of extracellular polymers, reducing microwave energy consumption, understanding the non-thermal effects of microwaves, promoting AD of sludge in combination with other chemical and physical methods, and expanding the application of the technology, are the main scientific focuses. Additionally, this paper thoroughly examines both the constraints and potential of microwave pretreatment technology for wastewater treatment.
Topics: Microwaves; Sewage; Wastewater; Waste Disposal, Fluid; Anaerobiosis
PubMed: 38532216
DOI: 10.1007/s11356-024-32931-9 -
Bioengineered Dec 2023Among the waste generated at oil refineries, secondary sludge from biological wastewater treatment processes (activated sludge systems) stands out. This paper aimed to... (Review)
Review
Among the waste generated at oil refineries, secondary sludge from biological wastewater treatment processes (activated sludge systems) stands out. This paper aimed to assess the use of anaerobic digestion (AD) to treat sludge by SWOT (Strength, Weakness, Opportunity, and Threat) analysis, ranking the different factors based on sustainability criteria. Additionally, the SWOT factors were matched (TOWS matrix) to help interpret the results. AD was found to be compatible with sustainability. The results demonstrated that the strength of AD (reduced organic load) compensates for its weaknesses (need for operational control and initial implementation costs), thereby avoiding the threat (sludge composition) and making the most of the opportunity (lower disposal cost). AD and co-digestion (added with food waste) used to treat oil refinery sludge showed that around 60% of the factors analyzed were confirmed experimentally. It was concluded that AD should be considered in the sustainable treatment of oil refinery waste activated sludge, especially when mixed with other readily biodegradable wastes.
Topics: Sewage; Anaerobiosis; Food; Refuse Disposal; Oil and Gas Industry; Bioreactors; Waste Disposal, Fluid
PubMed: 37394886
DOI: 10.1080/21655979.2023.2229092 -
[Recent advances in the structure and function of microbial community in anaerobic granular sludge].Sheng Wu Gong Cheng Xue Bao = Chinese... Nov 2023Anaerobic granular sludge (AnGS), a self-immobilized aggregate containing various functional microorganisms, is considered as a promising green process for wastewater... (Review)
Review
Anaerobic granular sludge (AnGS), a self-immobilized aggregate containing various functional microorganisms, is considered as a promising green process for wastewater treatment. AnGS has the advantages of high volume loading rate, simple process and low excess sludge generation, thus shows great technological and economical potentials. This review systematically summarizes the recent advances of the microbial community structure and function of anaerobic granular sludge, and discusses the factors affecting the formation and stability of anaerobic granular sludge from the perspective of microbiology. Moreover, future research directions of AnGS are prospected. This review is expected to facilitate the research and engineering application of AnGS.
Topics: Sewage; Waste Disposal, Fluid; Anaerobiosis; Microbiota; Water Purification; Bioreactors
PubMed: 38013181
DOI: 10.13345/j.cjb.230219 -
Journal of Environmental Management Feb 2024A series of technologies have been employed in pilot-scale to process digestate, i.e. the byproduct remaining after the anaerobic digestion of agricultural and other...
A series of technologies have been employed in pilot-scale to process digestate, i.e. the byproduct remaining after the anaerobic digestion of agricultural and other wastes, with the aim of recovering nutrients and reducing the load of solids and organics from it, hence improving the quality of digestate for potential subsequent reuse. In this case the digestate originated from a mixture of dairy and animal wastes and a small amount of agricultural wastes. It was processed by the application of several treatments, applied in series, i.e. microfiltration, ultrafiltration, reverse osmosis, selective electrodialysis and combined UV/ozonation. The initially applied membrane filtration methods (micro- and ultra-filtration) removed most of the suspended solids and macromolecules with a combined efficiency of more than 80%, while the reverse osmosis (at the end) removed almost all the remaining solutes (85-100%), producing sufficiently clarified water, appropriate for potential reuse. In the selective electrodialysis unit over 95% of ammonium and potassium were recovered from the feed, along with 55% of the phosphates. Of the latter, 75% was retrieved in the form of struvite.
Topics: Animals; Anaerobiosis; Phosphates; Struvite; Ammonium Compounds; Nutrients
PubMed: 38280247
DOI: 10.1016/j.jenvman.2024.120166 -
Bioresource Technology Dec 2023The study synthesised the raw liquid fraction of digestate into a nutrient rich solid digestate through acidification whilst preventing nitrogen loss through ammonium...
The study synthesised the raw liquid fraction of digestate into a nutrient rich solid digestate through acidification whilst preventing nitrogen loss through ammonium volatilisation during evaporation. To stabilise ammonium in the digestate, it was acidified with sulphuric, nitric, and phosphoric acid to produce solid digestate with ammonium sulphate, ammonium nitrate and ammonium phosphate, respectively. These treatments were compared against urea ammonium nitrate, raw digestate, and unacidified solid digestate. To evaluate the effect of these transformed digestate products in soil, a plant growth experiment (Kikuyu; Cenchrus clandestinus) was conducted, and characterised, plant growth, soil chemistry, and rhizosphere bacterial communities. Plant growth was enhanced by all digestate treatments compared to control and urea ammonium nitrate. Ammonium phosphate solid digestate plant growth was significantly higher than all other acidified treatments due to the high P content. Moreover, digestate-amended soil had elevated Proteobacteria and putative denitrification genes.
Topics: Food; Refuse Disposal; Anaerobiosis; Soil; Nitrogen; Nutrients; Ammonium Compounds; Urea
PubMed: 37844804
DOI: 10.1016/j.biortech.2023.129869 -
The ISME Journal Nov 2023Propionate is a key intermediate in anaerobic digestion processes and often accumulates in association with perturbations, such as elevated levels of ammonia. Under such...
Propionate is a key intermediate in anaerobic digestion processes and often accumulates in association with perturbations, such as elevated levels of ammonia. Under such conditions, syntrophic ammonia-tolerant microorganisms play a key role in propionate degradation. Despite their importance, little is known about these syntrophic microorganisms and their cross-species interactions. Here, we present metagenomes and metatranscriptomic data for novel thermophilic and ammonia-tolerant syntrophic bacteria and the partner methanogens enriched in propionate-fed reactors. A metagenome for a novel bacterium for which we propose the provisional name 'Candidatus Thermosyntrophopropionicum ammoniitolerans' was recovered, together with mapping of its highly expressed methylmalonyl-CoA pathway for syntrophic propionate degradation. Acetate was degraded by a novel thermophilic syntrophic acetate-oxidising candidate bacterium. Electron removal associated with syntrophic propionate and acetate oxidation was mediated by the hydrogen/formate-utilising methanogens Methanoculleus sp. and Methanothermobacter sp., with the latter observed to be critical for efficient propionate degradation. Similar dependence on Methanothermobacter was not seen for acetate degradation. Expression-based analyses indicated use of both H and formate for electron transfer, including cross-species reciprocation with sulphuric compounds and microbial nanotube-mediated interspecies interactions. Batch cultivation demonstrated degradation rates of up to 0.16 g propionate L day at hydrogen partial pressure 4-30 Pa and available energy was around -20 mol propionate. These observations outline the multiple syntrophic interactions required for propionate oxidation and represent a first step in increasing knowledge of acid accumulation in high-ammonia biogas production systems.
Topics: Propionates; Ammonia; Anaerobiosis; Bacteria; Acetates; Methanobacteriaceae; Euryarchaeota; Formates; Hydrogen; Methane
PubMed: 37679429
DOI: 10.1038/s41396-023-01504-y -
Cancer Immunology, Immunotherapy : CII Dec 2023Even in present-day times, cancer is one of the most fatal diseases. People are overwhelmed by pricey chemotherapy, immunotherapy, and other costly cancer therapies in... (Review)
Review
INTRODUCTION
Even in present-day times, cancer is one of the most fatal diseases. People are overwhelmed by pricey chemotherapy, immunotherapy, and other costly cancer therapies in poor and middle-income countries. Cancer cells grow under anaerobic and hypoxic conditions. Pyruvate is the final product of the anaerobic glycolysis pathway, and many cancer cells utilize pyruvate for their growth and development. The anaerobic microbiome produces many anti-cancer substances that can act as anti-tumor agents and are both feasible and of low cost. There are different mechanisms of action of the anaerobic microbiome, such as the production of short-chain fatty acids (SCFAs), and competition for the anaerobic environment includes the metabolic product pyruvate to form lactic acid for energy.
KEY FINDINGS
In this review, we have summarized the role of the metabolic approach of the anaerobic human microbiome in cancer prevention and treatment by interfering with cancer metabolite pyruvate. SCFAs possess decisive outcomes in condoning almost all the hallmarks of cancer and helping the spread of cancer to other body parts. Studies have demonstrated the impact and significance of using SCFA, which results from anaerobic bacteria, as an anti-cancer agent. Anaerobic bacteria-based cancer therapy has become a promising approach to treat cancer using obligate and facultative anaerobic bacteria because of their ability to penetrate and increase in an acidic hypoxic environment.
SIGNIFICANCE
This review attempts to provide the interconnection of cancer metabolism and anaerobic microbiome metabolism with a focus on pyruvate metabolism to understand and design unique anaerobic microbiota-based therapy for cancer patients.
Topics: Humans; Anaerobiosis; Microbiota; Neoplasms; Pyruvates; Bacteria, Anaerobic
PubMed: 37882845
DOI: 10.1007/s00262-023-03551-y -
MBio Oct 2023The key atherosclerotic TMAO originates from the initial gut microbial conversion of -carnitine and other dietary compounds into TMA. Developing therapeutic strategies...
The key atherosclerotic TMAO originates from the initial gut microbial conversion of -carnitine and other dietary compounds into TMA. Developing therapeutic strategies to block gut microbial TMA production needs a detailed understanding of the different production mechanisms and their relative contributions. Recently, we identified a two-step anaerobic pathway for TMA production from -carnitine through initial conversion by some microbes into the intermediate γBB which is then metabolized by other microbes into TMA. Investigational studies of this pathway, however, are limited by the lack of single microbes harboring the whole pathway. Here, we engineered strain to harbor the whole two-step pathway and optimized the expression through cloning a specific chaperone from the original host. Inoculating germ-free mice with this recombinant is enough to raise serum TMAO to pathophysiological levels upon L-carnitine feeding. This engineered microbe will facilitate future studies investigating the contribution of this pathway to cardiovascular disease.
Topics: Mice; Animals; Anaerobiosis; Disease Models, Animal; Carnitine; Methylamines; Metabolic Networks and Pathways; Choline
PubMed: 37737636
DOI: 10.1128/mbio.00937-23 -
Environmental Science & Technology Dec 2023Successfully addressing the complex global sanitation problem is a massive undertaking. Anaerobic digestion (AD), coupled with post-treatment, has been identified as a... (Review)
Review
Successfully addressing the complex global sanitation problem is a massive undertaking. Anaerobic digestion (AD), coupled with post-treatment, has been identified as a promising technology to contribute to meeting this goal. It offers multiple benefits to the end users, such as the potential inactivation of pathogenic microorganisms in waste and the recovery of resources, including renewable energy and nutrients. This feature article provides an overview of the most frequently applied AD systems for decentralized communities and low- and lower-middle-income countries with an emphasis on sanitation, including technologies for which pathogen inactivation was considered during the design. Challenges to AD use are then identified, such as experience, economics, knowledge/training of personnel and users, and stakeholder analysis. Finally, accelerators for AD implementation are noted, such as the inclusion of field studies in academic journals, analysis of emerging contaminants, the use of sanitation toolboxes and life cycle assessment in design, incorporation of artificial intelligence in monitoring, and expansion of undergraduate and graduate curricula focused on Water, Sanitation, and Hygiene (WASH).
Topics: Anaerobiosis; Artificial Intelligence; Sanitation; Technology; Water; Water Supply
PubMed: 37956995
DOI: 10.1021/acs.est.3c05291