Nitrogen Production Research Articles

Fire Reduces Soil Nitrate Retention While Increasing Soil Nitrogen Production and Loss Globally.

Elucidating the response of soil gross nitrogen (N) transformations to fires could improve our understanding of how fire affects N availability and loss. Yet, how internal soil gross N transformation rates respond to fires remains unexplored globally. Here, we investigate the general response of gross soil N transformations to fire and its consequences for N availability and loss. The results showed that fire increased gross N mineralization rate (GNM; +38%) and ammonium concentration (+47%) as a result of decreased soil C/N ratio but decreased microbial nitrate immobilization (INO3; -56%), resulting in increased nitrous oxide (N2O; +50%) and nitric oxide (+121%) emissions and N leaching (+308%). Time since fire affected soil N cycling and loss. Fire increased GNM, ammonium concentration, and N2O emission, and decreased INO3 only when time since fire was less than one year, while increased N leaching in the short (<one year) and long (>one year) terms. Thus, the consequences of fire were a short-lived increase in N availability and N2O emissions (lasting less than one year) but with persistent risks of N loss by leaching over time. Overall, fire increased the potential risks of N loss by stimulating N production and inhibiting nitrate retention.

Rapid Adaption but Genetic Diversity Loss of a Globally Distributed Diatom in the Warmer Ocean.

Studies have demonstrated that marine phytoplankton can adapt to the warmer environment. However, the underlying mechanisms remain largely unknown. Here, we quantified the capacity of a globally distributed marine diatom Skeletonema dohrnii, for rapid evolution under the moderate (24°C) and severe (28°C) warming scenarios. Whole-genome resequencing analysis revealed that the evolutionary adaptation of S. dohrnii to moderate warming was slow (i.e., 700 generations), whereas it was rapid (i.e., 300 generations) under severe warming but suffered a substantial loss of genetic diversity within the population. Genes associated with energy production and lipid metabolism evolved rapidly, particularly under severe warming, suggesting their vital roles in thermal adaptation. Proteomic results also showed the enhanced expression of proteins involved in energy production and lipid metabolism, especially under severe warming. Furthermore, particulate organic carbon and nitrogen production was greatly enhanced in the moderate warming-selected population but increased insignificantly in the severe warming-selected population, indicating more rapid adaptation driven by severe warming. Our results provide molecular insights into the rapid but limited evolution of thermal adaptation in marine diatoms and highlight energy production and lipid metabolism as the most important adaptive strategy. Future warming will affect genetic diversity and population dynamics of diatoms in the ocean.

What is the impact of neutral detergent fibre digestibility on productive performance of beef cattle fed tropical forages?

Our objective was to quantify the relationship between total neutral detergent fibre (NDF) digestibility and nutritional and productive characteristics in cattle fed tropical forages using a meta-analytical approach. The dataset used to develop this work was compiled from 24 experiments carried out with beef cattle in Brazil, published between 2005 and 2020, and totalising 115 treatment means. All the experiments were carried out using change-over designs and included a control treatment (i.e., only forage). There was a linear and positive relationship (P<0.01) between total NDF digestibility and voluntary forage intake. We estimated a 0.17 g/kg body weight increase in forage intake for each percentage point (i.e., 0.01 g/g) of improvement in NDF digestibility. On average, increasing total NDF digestibility caused a linear improvement (P<0.01) in rumen microbial nitrogen production (NMIC) and in dietary digested organic matter (DOM). The total NDF digestibility was linear and positively associated with nitrogen balance (NB, P<0.01). However, the increment in NB as a response to total NDF digestibility was more prominent as dietary NDF decreased (P<0.01). In summary, we concluded that increasing NDF digestibility in cattle fed tropical forage-based diets improves the voluntary forage intake and the supply of energy and metabolisable protein. This simultaneous effect causes an increase in the animal's nitrogen accretion and weight gain, but this effect will be more prominent as the dietary content of neutral detergent fibre decreases.

A synthetic co-culture for bioproduction of ammonia from methane and air.

Fixed nitrogen fertilizers feed fifty percent of the global population, but most fixed nitrogen production occurs using energy-intensive Haber-Bosch-based chemistry combining nitrogen (N2) from air with gaseous hydrogen (H2) from methane (CH4) at high temperatures and pressures in large-scale facilities sensitive to supply chain disruptions. This work demonstrates the biological transformation of atmospheric nitrogen (N2) into ammonia (NH3) using methane (CH4) as the sole carbon and energy source in a single vessel at ambient pressure and temperature, representing a biological 'room-pressure and room-temperature' route to ammonia (NH3) that could ultimately be developed to support compact, remote, ammonia (NH3) production facilities amenable to distributed biomanufacturing. The synthetic microbial co-culture of engineered methanotroph Methylomicrobium buryatense (now Methylotuvimicrobium buryatense) and diazotroph Azotobacter vinelandii converted three methane (CH4) molecules to L-lactate (C3H6O3) and powered gaseous nitrogen (N2) conversion to ammonia (NH3). The design used division of labor and mutualistic metabolism strategies to address the oxygen sensitivity of nitrogenase and maximize methane oxidation efficiency. Media pH and salinity were central variables supporting co-cultivation. Carbon concentration heavily influenced ammonia production. Smaller scale ammonia (NH3) production near dispersed, abundant, and renewable methane (CH4) sources could reduce disruption risks and capitalize on untapped energy resources.

Application of high-hydrostatic pressure to extend shelf life of miso-marinated escolar loins during cold storage

The changes in the microbiological and chemical qualities of escolar meat following high-pressure processing (HPP) (300–600 MPa, 5 min) along with miso marinade for 15 days with refrigeration were evaluated. Miso marinade and HPP treatment of escolar meat had synergistic inactivating effects on microorganisms that were more pronounced at higher pressures. In addition, when stored at 4 °C, the combination of miso marinade and HPP treatment significantly delayed microbial growth and total volatile basic nitrogen (TVBN) production and inhibited pH changes. Using TVBN <25 mg/100 g as the criterion for freshness, miso marinade and HPP treatment (300–600 MPa) extended the refrigerated storage period from 3 days without treatment and 6 days with miso marinade alone to 15 days. In addition, high-throughput sequencing analysis showed that the combination of miso marinade and HPP treatment significantly altered the microbiome of the fish during refrigeration, thereby slowing the spoilage process. This study demonstrated that miso marinade along with HPP treatment can improve color and texture, inhibit microbial growth, delay quality deterioration, and prolong the shelf life of fish meat. Therefore, high pressure together with miso marinade is an effective hurdle technique for improving the quality and freshness of aquatic products.

Urine luck: Environmental assessment of yellow water management in buildings for urban agriculture

The increasing global demand for agricultural production poses challenges to maintain the needs for critical fertilizers such as nitrogen. This study explores the potential of human urine as a source of renewable nitrogen for fertilizer production. Through a life cycle assessment, three different urine management strategies were compared: (S1) an artificial wetland, (S2) an on-site lab-scale aerobic reactor for nitrogen recovery, and (S3) a centralized wastewater treatment plant. While scenario S2 had the highest impacts in 6 out of 8 categories, an advantage in marine eutrophication was identified. S2 showed high energy demand (750 kg MJ-eq) and ecotoxicity (602 kg 1.4-DCB-eq.) mainly due to energy requirements. Nitrogen production exceeded 2.3 times the yearly nitrogen demands of the building tomato production. Upscaling S2 reduces impacts up to 2 times, lowering the payback time from 29 to 13 years. Therefore, implementing large-scale nitrogen recovery systems in cities is encouraged.

Antioxidants as adjuvant in cancer therapy: A systematic review

While cancer therapies can effectively remove malignant cells from the body, their efficacy is mostly limited to a number of harmful side effects. Antioxidant treatment is therefore frequently necessary to lessen these negative effects by lowering reactive species levels and minimizing chronic oxidative damage. Antioxidants have a crucial role in inhibiting the production of reactive nitrogen and oxygen species as well as their activities. Reviewing the role of antioxidants in the development or prevention of cancer was the goal of this study. It is thought that antioxidants can both prevent and treat different kinds of cancer. As of right now, cancer prevention and treatment have primarily involved consuming natural antioxidant substances. These are unquestionably cell-type- and Reactive Oxygen Species (ROS)-specific, as evidenced by alterations in gene expression, cellular activities, and mechanisms of cell death. By decreasing hydrogen donors or quenching singlet oxygen and postponing oxidative reactions in cancer cells that are actively developing, natural antioxidants eliminate an overabundance of free radical intermediates. The primary topics covered in this study are antioxidant categorization, metabolic regulation, and antioxidant involvement in cancer treatment.

Effects of nitrogen fertilization and micro-sprinkler irrigation on soil water and nitrogen contents, their productivities, bulb yield and economics of winter onion production

Abstract Onion is sensitive to soil water stress and nitrogen limitations, causing a marked reduction in yield and bulb quality. A field trial was set in the winter seasons of 2016–17 and 2017–18 to evaluate the effects of three micro-sprinkler irrigation levels at 0.6, 0.9 and 1.2 ratios of crop evapotranspiration (ETc) and four nitrogen levels at 0, 75, 100 and 120% of the recommended nitrogen dose (RDN), including surface irrigation at 40 mm cumulative pan evaporation (CPE) with 100% RDN (SN) using an augmented strip plot design on water and N distribution in soil, their productivities, onion yield and economics. Results indicated that the root zone water content increased by 5.2% for 1.2 ETc, and 1.4% for 0.9 ETc over the cropping period, but declined by 1.5% for 0.6 ETc with micro-sprinkler irrigation compared to surface irrigation with nitrogen fertilization (SN). The largest total root zone water depletion was in 1.2 ETc (16.7%), followed by SN (15.3%) and 0.9 ETc (15.0%). The high irrigation regime produced the maximum yield and nitrogen productivity, whereas deficit irrigation displayed the greatest water productivity. However, the coupling of micro-sprinkler irrigation at 1.2 ETc and 120% RDN led to an increase of onion bulb yield (22.6%), water productivity (42.7%), plant N uptake (29.0%) and net income (30.6%) with maximum benefit-cost ratio (3.19) compared to SN. However, as this study was only based on two seasons, more field trials will be needed to confirm the optimum amount of water and nitrogen for winter onion.

Effect of chloride ions on the reactive species change pathway and removal performance in the MW/Co2+/PMS process

Efficient removal of refractory organic matter is the focus of research in the treatment of actual wastewater with Peroxymonosulfate-based advanced oxidation processes(PMS-AOPs). However, the high concentration of chloride ions (Cl−) ubiquitously present in wastewater changes the reactive species (RS) present in the process, and the mechanism of this change is still not clear. This study investigated the effects of Cl− on the transformation behavior of RS and treatment performance under microwave (MW) combined with cobalt ions (Co2+)-activated PMS. The results showed that increasing the Cl− concentration can enhance the removal performance of the MW/Co2+/PMS process for ammonia (NH4+-N), accompanied by the production of nitrate nitrogen (NO3-N), monochloramine (NH2Cl) and dichloramine (NHCl2), which was related to the transformation of existing reactive oxygen species (ROS, •OH and SO4•−) into reactive chlorine species (RCS), with hypochlorous acid (HClO) as an important intermediate. Cl− can generate HClO through free radical oxidation (•OH and SO4•−) dominance and non-free radical oxidation (PMS and Co3+) promotion, and the heat transferred by MW can further trigger conversion between HClO and PMS, thereby changing the distribution of RS. Increasing the dosage of PMS and the dosage of Co2+ promoted the transformation of Cl− to reactive species in the MW/Co2+/PMS process. At MW power=160 W, [Co2+]=17.5 μM,[PMS]=10 mM, and [Cl−]=17 mM, the maximum cumulative [HClO] reached 1910.97 μM, and the decay rate was 0.1815 min−1.The macromolecular organic matter in aqueous environment competes with ammonia for the RCS. Through regulating [Cl−] in mature leachate, RCS has a certain oxidation effect to organic matter, but its limited oxidation ability leads to a decrease in the mineralization effect.

Novel heavy fuel oil based IGCC polygeneration system based on integration with ejector cooling and heat recovery of the solid oxide fuel cell in adsorption desalination

An innovative polygeneration system based on the gasification of heavy fuel oil including Orimulsion, Mazut, and Asphaltene has been proposed. In this system, electricity, hot water, cooling, hydrogen, fresh water, and nitrogen are produced in an innovative way to improve the system. In this regard, the integration of an Integrated Gasification Combined Cycle-Organic Rankine Cycle- Ejectero Refrigeration Cycle-Solid Oxide Fuel Cell-Adsorbation Deselination-Polyer Electron Electrolyzer has been proposed. The proposed system was investigated from the points of view of energy, exergy, exergoeconomic, and exergoenvironmental. In addition, to model the air separation unit, machine learning techniques have been employed.The results show that if Mazut is used as a gasification material, the system will have 36.81 %, 33.3 %, and 66.22 mPts/kWh in terms of polygeneration energy efficiency, polygeneration exergy efficiency and Levelized environmental impact of electricity, respectively and if Orimulsion is used, the Levelized cost of electricity value will be 33.32$/MWh which are the best performance in three fuel. Nitrogen production in this system is 35.08 kg/s, and hydrogen production is 0.0051 kg/s. The value of specific daily water production in the AD unit is 8.40 m3watertonofsilicagelper day, and the flow of hot water produced is 7.37 kg/s.

Comparison of Nitrous Oxide Consumption of Paddy Soils Developed from Three Parent Materials in Subtropical China

Paddy soils developed from various parent materials are widely distributed in the subtropical region in China and have a non-negligible but unclear potential to consume nitrous oxide (N2O) due to long-term flooding. This study selected three of the most common paddy soils in subtropical China, developing from quaternary red soil (R), lake sediment sand (S), and alluvial soil (C), to study their total N2O consumption and total nitrogen (N2) production using N2-free microcosm experiments. These paddy soils were treated with N2O addition (N2O treatment) or helium (He) addition (CK treatment) and incubated under flooding and anoxic conditions. The results showed that three alluvial soils (C1, C2, and C3) consumed over 99.93% of the N2O accumulated in the soil profile, significantly higher than R and S soils (p &lt; 0.05). And the N2 production in three C soils was also significantly higher than other soils, accounting for 81.61% of the total N2O consumption. The main soil factors affecting N2O consumption in C, S, and R soils were soil clay content (p &lt; 0.05), soil sand content (R2 = 0.95, p &lt; 0.001), and soil available potassium (AK) (p &lt; 0.01), respectively. These results indicate flooding paddy soils, no matter the parent materials developed, could consume extremely large amount of N2O produced in soil profiles.

Hybrid system for nitric oxide and hydrogen production

The device for nitric oxide inhalation therapy TIANOX has been put into use in clinical practice. It produces NO in nonequilibrium plasma of a diffusive spark discharge in the air at atmospheric pressure. There is a tendency to use a therapeutic gas mixture with high NO concentration for inhalation in the developing medical treatment methods. Nitric oxide transition into active compounds such as nitric dioxide, peroxynitrite, and nitrotyrosine can lead to oxidative stress. The use of hydrogen as an antioxidant that decreases the levels of hydroxyl radicals and peroxynitrite can protect cells from oxidative damage. Positive effect of the nitric oxide mixture and hydrogen is shown in the experiments with animals.The aim of the article is to describe development and performance the first hybrid system producing nitric oxide and hydrogen that was created in Federal State Unitary Enterprise “Russian Federal Nuclear Center – All-Russian Research Institute of Experimental Physics”. The system is based on the plasmochemical generator Tianox and the hydrogen generator, which is based on the electrolyzer with a solid polymeric electrolyte. It is fitted with H2, NO, and NO2 monitor and provides a continuous monitoring of concentrations of these gases and helps ensure safety of medical procedures by disconnecting NO and H2 generators at the moment when the gas concentrations exceed maximum levels (H2max, NOmax, NO2max).Conclusion. This hybrid system for nitrogen and hydrogen production passed the first study in human successfully. The preclinical studies also demonstrated its efficacy and safety.

Nitrogen fixation in the North Atlantic supported by Gulf Stream eddy-borne diazotrophs

Mesoscale oceanic eddies contribute to the redistribution of resources needed for plankton to thrive. However, due to their fluid-trapping capacity, they can also isolate plankton communities, subjecting them to rapidly changing environmental conditions. Diazotrophs, which fix dinitrogen (N2), are key members of the plankton community, providing reactive nitrogen, particularly in large nutrient-depleted regions such as subtropical gyres. However, there is still limited knowledge about how mesoscale structures characterized by specific local environmental conditions can affect the distribution and metabolic response of diazotrophs when compared with the large-scale dynamics of an oceanic region. Here we investigated genetic diazotroph diversity and N2 fixation rates in a transect across the Gulf Stream and two associated eddies, a region with intense mesoscale activity known for its important role in nutrient transport into the North Atlantic Gyre. We show that eddy edges are hotspots for diazotroph activity with potential community connectivity between eddies. Using a long-term mesoscale eddy database, we quantified N2 fixation rates as up to 17 times higher within eddies than in ambient waters, overall providing ~21 µmol N m−2 yr−1 to the region. Our results indicate that mesoscale eddies are hotspots of reactive nitrogen production within the broader marine nitrogen cycle.

Influence of Acetylene Concentration on N2O and N2 Emissions from an Intensive Vegetable Soil under Anoxic and Oxic Conditions

Acetylene (C2H2) is often employed to assess soil total denitrification (N2O + N2) due to its ease of implementation. However, this technique underestimates soil denitrification in soils with low nutrient contents, particularly those supporting grain yields. To our knowledge, there are limited studies that have specifically investigated the impact of C2H2 on nutrient-rich vegetable soils, especially concerning the emissions of N2 and N2O and the nitrogenous gas product ratio (i.e., N2O/(N2O + N2)). In this study, we conducted both anoxic and oxic incubations at various C2H2 concentrations (0%, 0.01%, and 10%, v/v) and utilized a robotized sampling and analysis system to quantify soil N2, N2O, and CO2 emissions. Our findings revealed that the cumulative N2O production in soil treated with 10%C2H2 was significantly lower than that in soil treated with 0.01%C2H2 and soil without C2H2. Contrarily, high concentrations of C2H2 (10%, v/v) led to increased N2 production. Similar trends were observed under oxic conditions, where 10%C2H2 concentration did not enhance N2O production but markedly increased N2 and CO2 emissions. Moreover, the N2O/(N2O + N2) product ratio was notably higher in soils treated with 0%C2H2 compared to the 10%C2H2 treatment under anoxic conditions. These findings indicate that high concentrations of acetylene could facilitate the reduction of N2O to N2 and lead to underestimated soil total denitrification in vegetable soil, regardless of anoxic or oxic conditions. This discovery underscores the drawbacks when employing high concentrations of acetylene to evaluate actual total denitrification in intensive greenhouse vegetable soils, highlighting the necessity for further investigation into alternative methodologies.

Multifunctional bacterium induced carbonate precipitation with low nitrogen effectively remediates cadmium polluted water

Microorganism Induced Carbonate Precipitation (MICP) has emerged as an efficacious approach to address the issue of cadmium (Cd) contamination in water bodies. However, the associated production of ammonium nitrogen (NH4+-N) poses a significant challenge to the MICP. To tackle this, our research has developed a novel bacterium (UN-1), with dual MICP and NH4+-N degradation capabilities. We have elucidated the biogeochemical pathways of Cd2+ precipitation and NH4+-N degradation, characterized the micromorphology, phase composition, and crystallization of the MICP products, and identified the key factors influencing the MICP reaction. Our findings indicate that The UN-1-mediated MICP effectively removes Cd2+ at concentrations below 20 mg/L, reducing NH4+-N levels to 50 mg/L within 120 h. The predominant strains in UN-1 are Sporosarcina (24.35 %), Bacillus (31.36 %), Tumebacillus (6.89 %), Nitrospira (11.09 %), and Alkaliphilus (8.16 %). The bacterium employs urea enzymes UreA, UreB, and UreC for urea hydrolysis, thereby facilitating carbonate production, while the degradation of NH4+-N is mediated by hydroxylamine oxidase (HAO), nitrite reductase (NIR), and nitrate reductase (NAR). The resultant MICP products after Cd2+ removal are irregular spherical minerals, 200–300 nm in diameter, exhibiting well-developed single-crystal structures and high crystallinity. Their X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) patterns align with the characteristics of cadmium carbonate (CdCO3) minerals. Optimal conditions for the UN-1-led MICP reaction are identified as a pH range of 5.0 to 9.0 and a temperature range of 20 to 40 °C, the dissolved oxygen (DO) concentration in the water does not significantly impact the MICP. Furthermore, the study demonstrates that NH4+-N concentrations can be maintained at low levels under most conditions. This research introduces an innovative solution to the NH4+-N by-product challenge during Cd removal via MICP, laying a solid theoretical foundation for the development of a rapid, efficient, and eco-friendly remediation technology for Cd-contaminated waters.

Greenhouse gas emissions and mitigation potential of crop production in Northeast China

Agricultural management practices that reduce greenhouse gas (GHG) emissions have been identified as effective mitigation strategies. However, research on carbon emissions from major crops in Northeast China focuses on national and provincial data, overlooking city-scale variability and uncertainties, which prevents fine-scale assessment of crop emissions reduction potential. To address this, a life cycle assessment (LCA) combined with the Monte Carlo method was conducted to estimate the carbon footprint of rice, maize, and soybean production for different cities in Northeast China from 1991 to 2020. The results showed that the top one-third of cities with the highest total carbon emissions (TCE) account for approximately 40 % of the region's TCE. Nitrogen losses and production processes related to nitrogen fertilizer application were identified as the primary contributors to TCE from crop production, accounting for 29.6–62.5 % of the total, with a relative importance of 58.5–78.2 %. Scenario analysis indicated that optimizing nitrogen fertilizer management and reducing active nitrogen losses are the most effective strategies for reducing TCE from major crop production, offering a reduction potential of 34.5–60.6 %. Recommended strategies include phased application of nitrogen fertilizer, the addition of nitrification inhibitors, or using slow-release nitrogen fertilizers, combined with appropriate increases in crop planting density, straw return decomposition technologies and water-saving irrigation methods to reduce GHG emissions. These strategies aim to achieve low-carbon sustainable grain production and provide a foundation for exploring the emissions reduction potential of agricultural inputs and optimizing regional crop layouts, offering new insights for developing more effective GHG reduction strategies.

Electrocatalytic Nitrate Reduction for Brackish Groundwater Treatment: From Engineering Aspects to Implementation

In recent years, nitrate has emerged as a significant groundwater pollutant due to its potential ecotoxicity. In particular, nitrate contamination of brackish groundwater poses a serious threat to both ecosystems and human health and remains difficult to treat. A promising, sustainable, and environmentally friendly solution when biological treatments are not applicable is the conversion of nitrate to harmless nitrogen (N2) or ammonia (NH3) as a nutrient by electrocatalytic nitrate reduction (eNO3R) using solar photovoltaic energy. This review provides a comprehensive overview of the current advances in eNO3R for the production of nitrogen and ammonia. The discussion begins with fundamental concepts, including a detailed examination of the mechanisms and pathways involved, supported by Density Functional Theory (DFT) to elucidate specific aspects of ammonium and nitrogen formation during the process. Furthermore, the integration of artificial intelligence (AI) and machine learning (ML) offers promising advancements in enhancing the predictive power of DFT, accelerating the discovery and optimization of novel catalysts. In this review, we also explore various electrode preparation methods and emphasize the importance of in situ characterization techniques to investigate surface phenomena during the reaction process. The review highlights numerous examples of copper-based catalysts and analyses their feasibility and effectiveness in ammonia production. It also explores strategies for the conversion of nitrate to N2, focusing on nanoscale zerovalent iron as a selective material and the subsequent oxidation of the produced ammonia. Finally, this review addresses the implementation of the eNO3R process for the treatment of brackish groundwater, discussing various challenges and providing reasonable opinions on how to overcome these obstacles. By synthesizing current research and practical examples, this review highlights the potential of eNO3R as a viable solution to mitigate nitrate pollution and improve water quality.

Nanoscale Biochar for Fertilizer Quality Optimization in Waste Composting: Microbial Community Regulation

Conventional composting faces challenges of nitrogen loss, product instability, and limited humic substance formation. This study investigated the effects of nanoscale biochars (nano-BCs) derived from rice straw (nano-RSB) and corn stover (nano-CSB) on manure composting. A randomized design with five treatments was used: control, regular biochars (RSB and CSB), and nano-BCs. Nano-BCs, especially nano-CSB, significantly improved compost maturity and reduced phytotoxicity, achieving a 146.20 % germination index. They increased total nitrogen (55.09–63.64 %) and phosphorus (10.25–12.33 %) retention, reduced NH4+-N loss, and promoted nitrification. Nano-CSB showed the highest final NO3−-N content (8.63 g/kg). Bacterial richness and diversity increased by 25–30 % in nano-BC treatments, with selective enrichment of beneficial species. The unique properties of nano-BCs, including high surface area and microporous structure, improved nutrient retention and compost quality. Nano-BCs offers a promising solution for sustainable waste management and high-quality compost production in agriculture, significantly enhancing nutrient retention and microbial community regulation during composting process.

Grids of stellar models with rotation

Context. Grids of stellar evolution models with rotation using the Geneva stellar evolution code (GENEC) have been published for a wide range of metallicities. Aims. We introduce the last remaining grid of GENEC models, with a metallicity of Z = 10−5. We study the impact of this extremely metal-poor initial composition on various aspects of stellar evolution, and compare it to the results from previous grids at other metallicities. We provide electronic tables that can be used to interpolate between stellar evolution tracks and for population synthesis. Methods. Using the same physics as in the previous papers of this series, we computed a grid of stellar evolution models with GENEC spanning masses between 1.7 and 500 M⊙, with and without rotation, at a metallicity of Z = 10−5. Results. Due to the extremely low metallicity of the models, mass-loss processes are negligible for all except the most massive stars. For most properties (such as evolutionary tracks in the Hertzsprung-Russell diagram, lifetimes, and final fates), the present models fit neatly between those previously computed at surrounding metallicities. However, specific to this metallicity is the very large production of primary nitrogen in moderately rotating stars, which is linked to the interplay between the hydrogen- and helium-burning regions. Conclusions. The stars in the present grid are interesting candidates as sources of nitrogen-enrichment in the early Universe. Indeed, they may have formed very early on from material previously enriched by the massive short-lived Population III stars, and as such constitute a very important piece in the puzzle that is the history of the Universe.

Improvement of the valuable compounds of fish waste through solid-state fermentation with probiotics

The nutritional value of fish waste is increased by using solid-state fermentation with probiotic strains. The highest number of viable cells were observed in the fish waste substrate by two strains, namely Lactobacillus plantarium (MT-ZH193) and Pediococcus acidilactici (CNCM I-4622 - MA 18/5 M). The temperature of 38 °C, the moisture of 42 %, and dried non-alcoholic malt beverage waste (MBW) at 5 % were the optimal values for desired variables to achieve maximum number of viable cells during the 48-hour fermentation (12.8 Log cfu/gdw). As the fermentation time increased, fat decreased by 28 %. The production of non-protein nitrogen increased as the true protein reduced during solid-state fermentation due to protease enzyme activity. The inhibition percentage of free radicals increased during the 48-hour fermentation as compared with the non-fermented sample. The first day of fermentation showed the highest level of protease enzyme activity. The results showed that fermented fish waste was a good choice as a feed additive for livestock and poultry due to its high concentration of protein and digestibility. It is also rich in non-protein nitrogen and peptides with antioxidant characteristics.