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Scientific Reports Jun 2024In this work, the effect of moderate electromagnetic fields (2.5, 10, and 15 mT) was studied using an immersed coil inserted directly into a bioreactor on batch...
In this work, the effect of moderate electromagnetic fields (2.5, 10, and 15 mT) was studied using an immersed coil inserted directly into a bioreactor on batch cultivation of yeast under both aerobic and anaerobic conditions. Throughout the cultivation, parameters, including CO levels, O saturation, nitrogen consumption, glucose uptake, ethanol production, and yeast growth (using OD 600 measurements at 1-h intervals), were analysed. The results showed that 10 and 15 mT magnetic fields not only statistically significantly boosted and sped up biomass production (by 38-70%), but also accelerated overall metabolism, accelerating glucose, oxygen, and nitrogen consumption, by 1-2 h. The carbon balance analysis revealed an acceleration in ethanol and glycerol production, albeit with final concentrations by 22-28% lower, with a more pronounced effect in aerobic cultivation. These findings suggest that magnetic fields shift the metabolic balance toward biomass formation rather than ethanol production, showcasing their potential to modulate yeast metabolism. Considering coil heating, opting for the 10 mT magnetic field is preferable due to its lower heat generation. In these terms, we propose that magnetic field can be used as novel tool to increase biomass yield and accelerate yeast metabolism.
Topics: Saccharomyces cerevisiae; Biomass; Aerobiosis; Fermentation; Anaerobiosis; Ethanol; Magnetic Fields; Glucose; Bioreactors; Glycerol; Oxygen; Nitrogen
PubMed: 38834614
DOI: 10.1038/s41598-024-63628-1 -
Proceedings of the National Academy of... Jun 2024Understanding how microbial lipidomes adapt to environmental and nutrient stress is crucial for comprehending microbial survival and functionality. Certain anaerobic...
Understanding how microbial lipidomes adapt to environmental and nutrient stress is crucial for comprehending microbial survival and functionality. Certain anaerobic bacteria can synthesize glycerolipids with ether/ester bonds, yet the complexities of their lipidome remodeling under varying physicochemical and nutritional conditions remain largely unexplored. In this study, we thoroughly examined the lipidome adaptations of strain PF2803, a mesophilic anaerobic sulfate-reducing bacterium known for its high proportions of alkylglycerol ether lipids in its membrane, under various cultivation conditions including temperature, pH, salinity, and ammonium and phosphorous concentrations. Employing an extensive analytical and computational lipidomic methodology, we identified an assemblage of nearly 400 distinct lipids, including a range of glycerol ether/ester lipids with various polar head groups. Information theory-based analysis revealed that temperature fluctuations and phosphate scarcity profoundly influenced the lipidome's composition, leading to an enhanced diversity and specificity of novel lipids. Notably, phosphorous limitation led to the biosynthesis of novel glucuronosylglycerols and sulfur-containing aminolipids, termed butyramide cysteine glycerols, featuring various ether/ester bonds. This suggests a novel adaptive strategy for anaerobic heterotrophs to thrive under phosphorus-depleted conditions, characterized by a diverse array of nitrogen- and sulfur-containing polar head groups, moving beyond a reliance on conventional nonphospholipid types.
Topics: Phosphorus; Sulfur; Lipidomics; Nitrogen; Adaptation, Physiological; Sulfates; Bacteria, Anaerobic; Anaerobiosis
PubMed: 38833476
DOI: 10.1073/pnas.2400711121 -
Gut Microbes 2024The facultative anaerobic Gram-positive bacterium is a ubiquitous member of the human gut microbiota. However, it has gradually evolved into a pathogenic and multidrug...
The facultative anaerobic Gram-positive bacterium is a ubiquitous member of the human gut microbiota. However, it has gradually evolved into a pathogenic and multidrug resistant lineage that causes nosocomial infections. The establishment of high-level intestinal colonization by enterococci represents a critical step of infection. The majority of current research on has been conducted under aerobic conditions, while limited attention has been given to its physiological characteristics in anaerobic environments, which reflects its natural colonization niche in the gut. In this study, a high-density transposon mutant library containing 26,620 distinct insertion sites was constructed. Tn-seq analysis identified six genes that significantly contribute to growth under anaerobic conditions. Under anaerobic conditions, deletion of (encoding Fe-S cluster assembly protein B) results in more extensive and significant impairments on carbohydrate metabolism compared to aerobic conditions. Consistently, the pathways involved in this utilization-restricted carbohydrates were mostly expressed at significantly lower levels in mutant compared to wild-type under anaerobic conditions. Moreover, deletion of or (encoding pyruvate formate lyase-activating protein A) led to failure of gastrointestinal colonization in mice. These findings contribute to our understanding of the mechanisms by which maintains proliferation under anaerobic conditions and establishes colonization in the gut.
Topics: Enterococcus faecium; Animals; Mice; Bacterial Proteins; Anaerobiosis; Iron-Sulfur Proteins; Gastrointestinal Tract; Gastrointestinal Microbiome; Gram-Positive Bacterial Infections; Humans; DNA Transposable Elements; Carbohydrate Metabolism; Female; Acetyltransferases
PubMed: 38831611
DOI: 10.1080/19490976.2024.2359665 -
Biochemistry. Biokhimiia Apr 2024Many microorganisms are capable of anaerobic respiration in the absence of oxygen, by using different organic compounds as terminal acceptors in electron transport...
Many microorganisms are capable of anaerobic respiration in the absence of oxygen, by using different organic compounds as terminal acceptors in electron transport chain. We identify here an anaerobic respiratory chain protein responsible for acrylate reduction in the marine bacterium Shewanella woodyi. When the periplasmic proteins of S. woodyi were separated by ion exchange chromatography, acrylate reductase activity copurified with an ArdA protein (Swoo_0275). Heterologous expression of S. woodyi ardA gene (swoo_0275) in Shewanella oneidensis MR-1 cells did not result in the appearance in them of periplasmic acrylate reductase activity, but such activity was detected when the ardA gene was co-expressed with an ardB gene (swoo_0276). Together, these genes encode flavocytochrome c ArdAB, which is thus responsible for acrylate reduction in S. woodyi cells. ArdAB was highly specific for acrylate as substrate and reduced only methacrylate (at a 22-fold lower rate) among a series of other tested 2-enoates. In line with these findings, acrylate and methacrylate induced ardA gene expression in S. woodyi under anaerobic conditions, which was accompanied by the appearance of periplasmic acrylate reductase activity. ArdAB-linked acrylate reduction supports dimethylsulfoniopropionate-dependent anaerobic respiration in S. woodyi and, possibly, other marine bacteria.
Topics: Shewanella; Electron Transport; Acrylates; Anaerobiosis; Oxidoreductases; Bacterial Proteins
PubMed: 38831506
DOI: 10.1134/S0006297924040096 -
Environmental Science & Technology Jun 2024This study explores the mechanisms enhancing phosphorus (P) release from sludge in anaerobic digestion (AD) with thermal hydrolysis pretreatment (THP) using sequential...
Enhancing Phosphorus Release from Sewage Sludge in Anaerobic Digestion via Thermal Hydrolysis Pretreatment: Insights from Phosphorus Speciation and Molecular Biological Pathways.
This study explores the mechanisms enhancing phosphorus (P) release from sludge in anaerobic digestion (AD) with thermal hydrolysis pretreatment (THP) using sequential chemical extraction, X-ray absorption near-edge structure spectroscopy (XANES), P NMR, and multiomics. THP-treated sludge notably increased liquid-phase P by 53.8% over 3 days compared to sewage sludge (SS), identifying solid-phase Fe-P as the primary P source. The THP+AD also provided a higher abundance of bacteria that contributed to P release through multiple pathways (MPRPB), whereas SS+AD enriched some microbial species with single P release pathway. Moreover, species co-occurrence network analysis underlined the pivotal role of P-releasing bacteria in THP+AD, with 8 out of 16 keystones being P-releasers. Among the 63 screened genes that were related to P transformations and release, the poly beta-hydroxybutyrate (PHB) synthesis genes associated with polyphosphate bacteria-mediated P release were more abundant in THP+AD than in SS+AD. Furthermore, the upregulation of genes involved in methyl phosphonate metabolism in the THP-treated sludge enhanced the methane production potential of the AD process. These findings suggested that MPRPB were indeed the main contributors to P release, and enrichment in the THP+AD process enhanced their capability for P liberation.
Topics: Phosphorus; Sewage; Anaerobiosis; Hydrolysis
PubMed: 38831418
DOI: 10.1021/acs.est.4c01287 -
Environmental Science and Pollution... Jun 2024The integrated system of anaerobic digestion and microbial electrolysis cells (AD-MEC) was a novel approach to enhance the degradation of food waste anaerobic digestate...
Enhanced degradation and methane production of food waste anaerobic digestate using an integrated system of anaerobic digestion and microbial electrolysis cells for long-term operation.
The integrated system of anaerobic digestion and microbial electrolysis cells (AD-MEC) was a novel approach to enhance the degradation of food waste anaerobic digestate and recover methane. Through long-term operation, the start-up method, organic loading, and methane production mechanism of the digestate have been investigated. At an organic loading rate of 4000 mg/L, AD-MEC increased methane production by 3-4 times and soluble chemical oxygen demand (SCOD) removal by 20.3% compared with anaerobic digestion (AD). The abundance of bacteria Fastidiosipila and Geobacter, which participated in the acid degradation and direct electron transfer in the AD-MEC, increased dramatically compared to that in the AD. The dominant methanogenic archaea in the AD-MEC and AD were Methanobacterium (44.4-56.3%) and Methanocalculus (70.05%), respectively. Geobacter and Methanobacterium were dominant in the AD-MEC by direct electron transfer of organic matter into synthetic methane intermediates. AD-MEC showed a perfect SCOD removal efficiency of the digestate, while methane as clean energy was obtained. Therefore, AD-MEC was a promising technology for deep energy transformation from digestate.
Topics: Methane; Anaerobiosis; Electrolysis; Food; Bioreactors; Food Loss and Waste
PubMed: 38829499
DOI: 10.1007/s11356-024-33525-1 -
BMC Biology Jun 2024Hydrogenosomes are a specific type of mitochondria that have adapted for life under anaerobiosis. Limited availability of oxygen has resulted in the loss of the...
BACKGROUND
Hydrogenosomes are a specific type of mitochondria that have adapted for life under anaerobiosis. Limited availability of oxygen has resulted in the loss of the membrane-associated respiratory chain, and consequently in the generation of minimal inner membrane potential (Δψ), and inefficient ATP synthesis via substrate-level phosphorylation. The changes in energy metabolism are directly linked with the organelle biogenesis. In mitochondria, proteins are imported across the outer membrane via the Translocase of the Outer Membrane (TOM complex), while two Translocases of the Inner Membrane, TIM22, and TIM23, facilitate import to the inner membrane and matrix. TIM23-mediated steps are entirely dependent on Δψ and ATP hydrolysis, while TIM22 requires only Δψ. The character of the hydrogenosomal inner membrane translocase and the mechanism of translocation is currently unknown.
RESULTS
We report unprecedented modification of TIM in hydrogenosomes of the human parasite Trichomonas vaginalis (TvTIM). We show that the import of the presequence-containing protein into the hydrogenosomal matrix is mediated by the hybrid TIM22-TIM23 complex that includes three highly divergent core components, TvTim22, TvTim23, and TvTim17-like proteins. The hybrid character of the TvTIM is underlined by the presence of both TvTim22 and TvTim17/23, association with small Tim chaperones (Tim9-10), which in mitochondria are known to facilitate the transfer of substrates to the TIM22 complex, and the coupling with TIM23-specific ATP-dependent presequence translocase-associated motor (PAM). Interactome reconstruction based on co-immunoprecipitation (coIP) and mass spectrometry revealed that hybrid TvTIM is formed with the compositional variations of paralogs. Single-particle electron microscopy for the 132-kDa purified TvTIM revealed the presence of a single ring of small Tims complex, while mitochondrial TIM22 complex bears twin small Tims hexamer. TvTIM is currently the only TIM visualized outside of Opisthokonta, which raised the question of which form is prevailing across eukaryotes. The tight association of the hybrid TvTIM with ADP/ATP carriers (AAC) suggests that AAC may directly supply ATP for the protein import since ATP synthesis is limited in hydrogenosomes.
CONCLUSIONS
The hybrid TvTIM in hydrogenosomes represents an original structural solution that evolved for protein import when Δψ is negligible and remarkable example of evolutionary adaptation to an anaerobic lifestyle.
Topics: Trichomonas vaginalis; Protein Transport; Protozoan Proteins; Mitochondrial Precursor Protein Import Complex Proteins; Mitochondria; Organelles
PubMed: 38825681
DOI: 10.1186/s12915-024-01928-8 -
Bioresource Technology Jul 2024Electro-fermentation (EF) was combined with anaerobic fermentation (AF) to promote medium-chain fatty acid (MCFA) from sewage sludge. Results showed that EF at...
Electro-fermentation (EF) was combined with anaerobic fermentation (AF) to promote medium-chain fatty acid (MCFA) from sewage sludge. Results showed that EF at acidification process significantly increased short-chain fatty acid (SCFA) production of by 0.5 times (82.4 mmol C/L). AF facilitated the chain elongation (CE) process by enhancing the SCFA conversion. Combined EF at acidification and AF at CE (EF-AF) achieved the highest MCFA production of 27.9 mmol C/L, which was 20 %-866 % higher than the other groups. Electrochemical analyses showed that enhanced SCFA and MCFA production was accompanied with good electrochemical performance at acidification and CE. Microbial analyses showed that EF-AF promoted MCFA production by enriching electrochemically active bacteria (EAB, Bacillus sp.). Enzyme analyses indicated that EF-AF promoted MCFA production by enriching the functional enzymes involved in Acetyl-CoA formation and the fatty acid biosynthesis (FAB) pathway. This study provided new insights into the production of MCFA from enhanced sewage sludge.
Topics: Sewage; Fermentation; Anaerobiosis; Fatty Acids; Fatty Acids, Volatile
PubMed: 38824969
DOI: 10.1016/j.biortech.2024.130917 -
Journal of Environmental Management Jun 2024The production of biogas from microalgae has gained attention due to their rapid growth, CO sequestration, and minimal land use. This study uses life cycle assessment to...
The production of biogas from microalgae has gained attention due to their rapid growth, CO sequestration, and minimal land use. This study uses life cycle assessment to assess the environmental impacts of biogas production from wastewater-grown microalgae through anaerobic digestion within an optimized microalgae-based system. Using SimaPro® 9 software, 3 scenarios were modeled considering the ReCiPe v1.13 midpoint and endpoint methods for environmental impact assessment in different categories. In the baseline scenario (S1), a hypothetical system for biogas production was considered, consisting of a high rate algal pond (HRAP), a settling, an anaerobic digester, and a biogas upgrading unit. The second scenario (S2) included strategies to enhance biogas yield, namely co-digestion and thermal pre-treatment. The third scenario (S3), besides considering the strategies of S2, proposed the biogas upgrading in the HRAP and the digestate recovery as a biofertilizer. After normalization, human carcinogenic toxicity was the most positively affected category due to water use in the cultivation step, accounted as avoided product. However, this category was also the most negatively affected by the impacts of the digester heating energy. Anaerobic digestion was the most impactful step, constituting on average 60.37% of total impacts. Scenario S3 performed better environmentally, primarily due to the integration of biogas upgrading within the cultivation reactor and digestate use as a biofertilizer. Sensitivity analysis highlighted methane yield's importance, showing potential for an 11.28% reduction in ionizing radiation impacts with a 10% increase. Comparing S3 biogas with natural gas, the resource scarcity impact was reduced sixfold, but the human health impact was 23 times higher in S3.
Topics: Biofuels; Microalgae; Wastewater; Anaerobiosis; Environment
PubMed: 38823295
DOI: 10.1016/j.jenvman.2024.121251 -
Water Science and Technology : a... May 2024Anaerobic treatment of oily substrate, known as grease trap waste (GTW), was investigated for its practicability via continuous stirred tank reactor (CSTR) at different...
Anaerobic treatment of oily substrate, known as grease trap waste (GTW), was investigated for its practicability via continuous stirred tank reactor (CSTR) at different operating conditions and selected recovery strategies of feeding frequency efficacy. This study determine the performance of feeding frequency efficacy, namely feeding every 24 hours (R) and feeding every 12 hours (R). Under organic loading rate (OLR) of 2.2 gCOD/L.day, R exhibited methane composition of 57%, methane production rate of 0.27 LCH/L.day, and methane yield of 0.14 LCH/gCOD. At the same OLR, R recorded methane composition of 60%, methane production rate of 0.29 LCH/L.day and similar methane yield as R. Findings indicated that R showed performance comparable to that of R. Given minor variation observed in performance, it is recommended that plant operators may consider scheduling two feedings per day for low loading conditions and switch to one feeding per day for higher loading conditions. This strategy is designed to balance the system and prevent shock loads, which could lead to plant shutdowns. This mechanism will induce their conversion to volatile fatty acids (VFAs); thus, reducing the risk of acid accumulation and pH drops, which could inhibit methanogens to produce methane, especially for oily substrate.
Topics: Bioreactors; Anaerobiosis; Biofuels; Methane; Waste Disposal, Fluid
PubMed: 38822615
DOI: 10.2166/wst.2024.153