Search Results (121)

Microorganisms such as methanogenic archaea play a key role in wastewater treatment plants (WWTPs) by breaking down organic matter and pollutants and producing methane, a potential renewable energy source. However, sulphate-reducing bacteria (SRB) compete with archaea for the same substrates under anaerobic conditions, lowering methane production and generating harmful hydrogen sulphide (H₂S). Inhibiting SRB is therefore crucial to enhance methane yield and reduce toxic by-products. By means of manual screening of public databases (KEGG, BRENDA, PDB, PubChem) 12 potential inhibitors of SRB were found. After computational ecotoxicological assessment, four candidates were selected, and one of them experimentally increased methane production, demonstrating that SRB inhibition favours the anaerobic digestion of sludges. In order to further explore new candidates, Quantitative Structure–Activity Relationship (QSAR) models were developed showing reliable predictive performance. These models enabled the virtual screening of COCONUT, a natural product database, identifying 73 potential SRB inhibitors. After an ecotoxicological assessment, five commercially available compounds remained. The identified candidates may reduce competition between SRB and methanogenic archaea, leading to higher methane production and supporting WWTPs in generating their own biogas. This would contribute to a circular economy and help mitigate greenhouse gas emissions. Full article

The growing demand for air connectivity, coupled with the forecasted increase in passengers by 2040, implies an exigency in the aviation sector to adopt sustainable approaches for net zero emission by 2050. Sustainable Aviation Fuel (SAF) is currently the most promising short-term solution; however, ensuring its overall sustainability depends on reducing the life cycle carbon footprints. A key challenge prevails in hydrogen usage as a reactant for the approved ASTM routes of SAF. The processing, conversion and refinement of feed entailing hydrodeoxygenation (HDO), decarboxylation, hydrogenation, isomerisation and hydrocracking requires substantial hydrogen input. This hydrogen is sourced either in situ or ex situ, with the supply chain encompassing renewables or non-renewables origins. Addressing this hydrogen usage and recognising the emission implications thereof has therefore become a novel research priority. Aside from the preferred adoption of renewable water electrolysis to generate hydrogen, other promising pathways encompass hydrothermal gasification, biomass gasification (with or without carbon capture) and biomethane with steam methane reforming (with or without carbon capture) owing to the lower greenhouse emissions, the convincing status of the technology readiness level and the lower acidification potential. Equally imperative are measures for reducing hydrogen demand in SAF pathways. Strategies involve identifying the appropriate catalyst (monometallic and bimetallic sulphide catalyst), increasing the catalyst life in the deoxygenation process, deploying low-cost iso-propanol (hydrogen donor), developing the aerobic fermentation of sugar to 1,4 dimethyl cyclooctane with the intermediate formation of isoprene and advancing aqueous phase reforming or single-stage hydro processing. Other supportive alternatives include implementing the catalytic and co-pyrolysis of waste oil with solid feedstocks and selecting highly saturated feedstock. Thus, future progress demands coordinated innovation and research endeavours to bolster the seamless integration of the cutting-edge hydrogen production processes with the SAF infrastructure. Rigorous techno-economic and life cycle assessments, alongside technological breakthroughs and biomass characterisation, are indispensable for ensuring scalability and sustainability. Full article

Background: Metabolic Syndrome (MetS) is a multifactorial condition characterized by insulin resistance, dyslipidemia, hypertension, and abdominal obesity, which collectively increase the risk of type 2 diabetes mellitus and cardiovascular diseases. Lifestyle modification represents the first-line strategy in its management, whereas pharmacological interventions are complex and typically require long-term polypharmacotherapy. In this context, natural bioactive compounds with pleiotropic effects are gaining increasing attention. Among these, S-allyl cysteine (SAC), the major sulfur-containing compound derived from black garlic, has been identified as a promising candidate due to its well-documented antioxidant and anti-inflammatory properties. Methods: This narrative review examines the pathophysiological mechanisms underlying MetS and summarizes current evidence on the protective role of SAC against key pathological features of this condition, including oxidative stress, inflammation, glucose and lipid dysmetabolism, endothelial dysfunction, and gut microbiota alterations. Results: Preclinical studies indicate that SAC counteracts lipid accumulation, insulin resistance, endothelial dysfunction, and gut dysbiosis through multiple mechanisms, including hydrogen sulfide release, reactive oxygen species scavenging, inhibition of advanced glycation end products, and modulation of metabolic pathways. Conclusions: SAC emerges as a promising nutraceutical for the prevention and management of MetS and its complications. This underscores the broader relevance of nutraceuticals as promising tools in mitigating metabolic dysfunctions and reducing the burden of cardiometabolic diseases. Full article

Anaerobic digestion is a well-known technology for renewable energy generation. Its efficiency depends on the substrate composition and its biodegradability. Microalgae are considered a promising feedstock due to their rapid growth, high protein and lipid content, and potential for wastewater treatment. However, the mono-digestion is often limited by a low carbon-to-nitrogen (C/N) ratio and a recalcitrant cell wall structure. This study evaluated the potential of co-digesting microalgal biomass with bakery waste under batch conditions. Two types of bakery residues (stale wheat bread and stale wheat rolls), were tested. Each was added to the microalgal biomass at proportions of 25%, 50%, and 75% based on volatile solids (VS). The experiment was carried out in a semi-technical anaerobic digester under mesophilic conditions. During the anaerobic digestion, the biogas volume, gas composition, and the energy potential of the substrates were analysed. The highest biogas yield (494.34 L·kg⁻¹ VS) was obtained from the mixture of microalgae and 75% bread. Although mono-digestion of microalgal biomass resulted in the highest methane concentration, the differences compared to co-digested samples were not significant. The lowest hydrogen sulphide concentration (234.20 ppm) was measured in the 25% rolls variant, while the control sample (100% microalgae) showed the highest H₂S levels. From an energy perspective, the most beneficial result was obtained with the addition of 75% bread. Full article

Plant growth-promoting rhizobacteria (PGPRs) colonise the rhizosphere and root surfaces, enhancing crop development through a variety of mechanisms. This study evaluated microbial strains isolated from Triticum aestivum L. for key plant growth-promoting traits, including indole-3-acetic acid (IAA) production, phosphate and zinc (Zn) solubilisation, nitrogen (N₂) fixation, and antifungal activity. Among 36 isolates, 3 (AS8, AS23, AS31) exhibited strong growth-promoting potential. IAA production, citrate assimilation, carbohydrate fermentation, and catalase activity were observed to a comparable extent among the selected strains. AS8 showed the highest protease, lipase, and amylolytic activity, while AS23 demonstrated superior phosphate and Zn solubilisation. Notably, AS31 emerged as the most promising multi-trait isolate, exhibiting the highest levels of IAA production, N₂ fixation, antifungal activity against five phytopathogens (Fusarium graminearum, F. solani, F. oxysporum, Pythium aphanidermatum, and Alternaria alternata), potentially linked to its hydrogen sulphide (H₂S) production, and cellulolytic activity. Molecular identification based on 16S rRNA gene sequencing revealed the isolates as Stenotrophomonas indicatrix AS8, Pantoea agglomerans AS23, and Bacillus thuringiensis AS31. Seed germination assays confirmed the plant growth-promoting efficacy of these PGPR strains, with vigour index increases of up to 43.4-fold. Given their positive impact on seed germination and significant Zn-solubilising abilities, the selected strains represent promising candidates for use as bio-inoculants, offering a sustainable and eco-friendly strategy to enhance agricultural productivity in nutrient-deficient soils. Future research should validate the efficacy of these PGPR strains under pot conditions to confirm their potential for practical agricultural applications. Full article

For a long time, D-amino acids remained unexplored in mammalian physiology. The technological advances in enantioseparation over the past 50 years have revealed that D-amino acids not only exist in human tissues and fluids but also play important roles in neurotransmission, immune regulation, and cellular proliferation. The present review provides a comprehensive assessment of the role of D-amino acids in cancer, including their endogenous and exogenous production pathways, along with the analytical methodologies used for detection and quantification, from liquid chromatography to biosensors. These methods have underlined how altered levels of D-amino acids can be helpful in early detection, progression, or response to treatment in several malignancies, including gastric, hepatic, colorectal, or breast cancer. The present review also explores how manipulation of D-amino acids can regulate cell proliferation, their mechanisms in cancer regulation, including the modulation of N-methyl-D-aspartate (NMDA) receptors and the production of hydrogen sulphide (H₂S), and the role of specific D-amino acids in cancer onset, immune defence, and protection against chemotherapy-induced toxicity. Finally, several underexplored research directions are outlined, such as potential correlations with gut microbiota composition, the impact of processed food consumption, and the integration of multiomics strategies. Full article

Biological reduction of sulphates has gradually replaced unit chemical processes for the treatment of acid mine drainage (AMD), which exerts a significant environmental impact due to its elevated acidity and high concentrations of heavy metals. Bioremediation is optimally suited for the treatment of AMD because it is cost-effective and efficient. Anaerobic bioremediation employing sulphate-reducing bacteria (SRB) presents a promising solution by facilitating the reduction of sulphate to sulphide. The formed can precipitate and immobilise heavy metals, assisting them in their removal from contaminated wastewater. This paper examines the current status of SRB-based bioremediation, with an emphasis on recent advances in microbial processes, reactor design, and AMD treatment efficiencies. Reviewed studies showed that SRB-based bioreactors can achieve up to 93.97% of sulphate reduction, with metal recovery rates of 95% for nickel, 98% for iron and copper, and 99% for zinc under optimised conditions. Furthermore, bioreactors that used glycerol and ethanol as a carbon source improved the efficiency of sulphate reduction, achieving a pH neutralisation from 2.8 to 7.5 within 14 days of hydraulic retention time. Despite the promising results achieved so far, several challenges remain. These include the need for optimal environmental conditions, the management of toxic hydrogen sulphide production, and the economic feasibility of large-scale applications. Future directions are proposed to address these challenges, focusing on the genetic engineering of SRB, integration with other treatment technologies, and the development of cost-effective and sustainable bioremediation strategies. Ultimately, this review provides valuable information to improve the efficiency and scalability of SRB-based remediation methods, contributing to more sustainable mining practices and environmental conservation. To ensure relevance and credibility, relevance and regency were used as criteria for the literature search. The literature sourced is directly related to the subject of the review, and the latest research, typically from the last 5 to 10 years, was prioritised. Full article

This study explores the impact of geographical origin, harvest time, and cooking on the volatile organic compound (VOC) profiles of wild and reared seabream from the Adriatic and Tyrrhenian Seas. A Proton Transfer Reaction–Time of Flight–Mass Spectrometry (PTR-ToF-MS) allowed for VOC profiling with high sensitivity and high throughput. A total of 227 mass peaks were identified. Principal component analysis (PCA) showed a clear separation between cooked and raw samples, with cooking causing a significant increase in 64% of VOCs, especially hydrogen sulphide, methanethiol, and butanal. A two-way ANOVA revealed significant effects of origin, time, and their interaction on VOC concentration, with 102 mass peaks varying significantly based on all three factors. Seasonal effects were also notable, particularly in reared fish from the Adriatic Sea, where compounds like monoterpenes and aromatics were higher during non-breeding months, likely due to environmental factors unique to that area. Differences between wild and reared fish were influenced by lipid content and seasonal changes, impacting the VOC profile of seabream. These findings provide valuable insights into how cooking, geographical origin, and seasonality interact to define the flavour profile of seabream, with potential applications in improving quality control and product differentiation in seafood production. Full article

Around the world, a significant proportion of sewers and sewer maintenance holes are constructed from concrete. Unfortunately, one major problem with concrete sewer infrastructure is corrosion caused by biogenic hydrogen sulphide, which causes major issues for concrete structural integrity. Furthermore, concrete may be significantly corroded and softened but still pass a visual inspection. The novel system presented in this paper uses a penetrometer mounted on a robotic platform to measure the depth of penetration through a corroded concrete surface. An angular mechanism is used to rotate the penetrometer to new positions as striking aggregate may result in false readings. Based on laboratory analysis, this design is capable of providing consistent and precise multiple observations for both smooth and rough surfaces, as well as for flat and curved surfaces, with 0.1 mm accuracy. The use of a remote robotic platform eliminates the hazards of confined space entry whilst providing a repeatable analysis platform. Full article

Biogas production offers an alternate method for managing agricultural waste and contributes to sustainable renewable energy generation. Anaerobic digestion (AD) enables the transformation of organic waste, including agricultural substrates, into biogas, mostly consisting of methane, carbon dioxide, and trace gases such as ammonia and hydrogen sulphide. The objective of this study was to employ a 30 L semi-continuous stirred tank reactor to evaluate the effects of organic loading rate, temperature, and speed of stirring on biogas production. The reactor was inoculated with 8.6 L and filled with 11.4 L of a mixed substrate including cattle manure, potato waste, potato starch waste, fruit waste, and expired dry dog food. The reactor was evaluated with organic loading rates (OLRs) of 11.2, 12.2, and 13.2 g VS/L d, and stirring speeds of 25.5, 35.5, and 45.5 rpm. The results indicated that the maximum yield was 12.2 g VS/L d at 45.5 rpm, and in thermophilic conditions, the biogas yield surpassed that of mesophilic conditions, measuring 105,860 NmL/g VS compared to 69,800 NmL/g VS. This study emphasises the significance of optimising operational parameters to improve biogas output, thereby contributing to sustainable energy resources and advancing the Sustainable Development Goals (SDGs). Full article

Salmonella spp. are known pathogens in fish, with their presence potentially resulting from the contamination of the aquatic environment or improper handling. Accurate bacterial identification is crucial across various fields, including medicine, microbiology, and the food industry, and thus a range of techniques are available for this purpose. In this study, Salmonella spp. and other hydrogen sulphide-positive bacteria were investigated in the digestive contents of fish destined for consumption from the Atlantic area of Macaronesia. Two identification techniques were compared: the traditional API method and the MALDI-TOF MS technique. For the identification of Salmonella spp. carriers, 59 samples were processed following ISO 6579–1:2017. A total of 47 strains of Gram-negative bacilli were obtained. No Salmonella spp. isolates were detected. The most frequent genus was Enterobacter (76.50%), followed by Shewanella (10.63%). The MALDI-TOF MS technique showed a high concordance with the API technique, with 72.34% concordance at the species level. Both techniques demonstrated a high degree of concordance in the identification of Enterobacter cloacae, with 87.23% genus-level concordance and 12.76% non-concordant identifications. This study highlights the limitations of the API technique and the speed and precision of MALDI-TOF MS. The identified bacteria could pose a health risk to humans. Full article

This study aims to assess the capability of using a specially designed device to monitor changes in gas concentration (CO₂, NH₃, H₂S, and O₂) in the atmosphere above the minced beef meat, during storage at refrigerated temperature. With its array of sensing channels, the multi-gas detector device facilitates the detection of precise gas concentrations in sensitive environments, enabling the monitoring of various processes occurring within stored meat. To delve into the connection between microbial activity and gas emissions during storage, fluctuations in microbial populations in the meat were observed, focusing on prevalent meat microbiota such as lactic acid bacteria (LAB) and Enterobacteriaceae. A significant reduction of O₂ content in the stored samples was observed after seven days (p < 0.05), while a significant release of CO₂ was detected on the fourth day of storage. Significant changes (p < 0.05) in the gas content were tracked until the 11th day of storage followed by intensive microbial growth. NH₃ and H₂S levels remained undetectable throughout the experiment. The results showed a correlation between an increase in gas content in the headspace and an increase in the number of LAB and Enterobacteriaceae in meat. Modern multi-gas detector devices can indirectly determine microbial contamination in closed meat packaging. Full article

With the aim of developing an innovative water treatment approach for developing countries in the Global South, we have applied the method of treating a cavitating water stream with a plasma discharge under real conditions. To this end, we have optimised the approach after investigating the effects that occur in the treated medium during such a treatment. Based on the obtained light absorption curves of treated model solutions of titanium oxysulphate and potassium bichromate, it was found that inside the reactor the main role in the destruction of chemical contaminants is played by hydroxide ions, while outside the reactor the main chemical interaction takes place with hydrogen peroxide. The plasma treatment unit was tested in the biological wastewater treatment plant of a health resort in the territory of the Russian Federation (Almetyevsk, Republic of Tatarstan). Water samples taken directly from the tertiary decantation tank were used as real wastewater samples instead of adding chemical reagents for disinfection. It was found that with different modes of operation of the plasma treatment plant, the concentration levels of coliform bacteria, coliphages and Escherichia coli decreased significantly and fell below the limit of permissible concentrations for wastewater discharge. At the same time, the possible effect of the plasma on persistent inorganic compounds was investigated. It was shown that the plasma discharge in the flow of the incoming liquid can almost completely destroy compounds that are difficult to remove, such as hydrogen sulphide and chlorides. In the course of the study, the optimum frequency of electrical pulses of 68 kHz was selected, which ensures the lowest consumption of electrical energy while maintaining the required efficiency. Full article

Myocardial ischaemia reperfusion injury (IRI) occurring from acute coronary artery disease or cardiac surgical interventions such as bypass surgery can result in myocardial dysfunction, presenting as, myocardial “stunning”, arrhythmias, infarction, and adverse cardiac remodelling, and may lead to both a systemic and a localised inflammatory response. This localised cardiac inflammatory response is regulated through the nucleotide-binding oligomerisation domain (NACHT), leucine-rich repeat (LRR)-containing protein family pyrin domain (PYD)-3 (NLRP3) inflammasome, a multimeric structure whose components are present within both cardiomyocytes and in cardiac fibroblasts. The NLRP3 inflammasome is activated via numerous danger signals produced by IRI and is central to the resultant innate immune response. Inhibition of this inherent inflammatory response has been shown to protect the myocardium and stop the occurrence of the systemic inflammatory response syndrome following the re-establishment of cardiac circulation. Therapies to prevent NLRP3 inflammasome formation in the clinic are currently lacking, and therefore, new pharmacotherapies are required. This review will highlight the role of the NLRP3 inflammasome within the myocardium during IRI and will examine the therapeutic value of inflammasome inhibition with particular attention to carbon monoxide, nitric oxide, and hydrogen sulphide as potential pharmacological inhibitors of NLRP3 inflammasome activation. Full article

Climate change and anthropogenic impacts drastically affect the biogeochemical regime of the Black Sea, which contains the largest volume of sulphidic water in the world. The Sea’s oxygen inventory depends on vertical mixing that transports dissolved oxygen (DO) from the upper euphotic layer to deeper layers and on dissolved oxygen consumption for the oxidation of organic matter (OM) and reduced species of S, Fe, and Mn. Here we use a vertical one-dimensional transport model, 2DBP, forced by Copernicus data, that was coupled with the FABM-family N-P-Si-C-O-S-Mn-Fe Bottom RedOx Model BROM. The research objective of this study was to analyze the oxygen budget in the upper 350 m of the Sea and demonstrate the role of the parameterization of the acceleration of the sinking of particles covered by precipitated Mn(IV). The analysis of the oxygen budget revealed distinct patterns in oxygen consumption within different depths. In the oxic zone, the primary sink for DO is the mineralization of organic matter, whereas in the suboxic zone, dissolved Mn(II) oxidation becomes the predominant sink. The produced Mn(IV) sinks down and reacts with hydrogen sulphide several meters below, making possible the existence of the suboxic layer without detectable concentrations of DO and H₂S. Full article