High Nitrogen Content Research Articles

Access the performance of nitrification in an activated sludge reactor for seafood wastewater treatment: Experiment on the SBR model at the lab-scale

Abstract A major challenge in wastewater treatment system design is optimizing the nitrification process in activated sludge reactors, especially in the seafood industry with high concentration of organic matter, fat, oil, and nitrogen. However, in traditional seafood wastewater treatment systems, nitrogen removal is limited by the ratio C:N:P ≈ 100:5:1. With the experiment of the Sequencing Batch Reactor model, the evaluation of biological nitrification reaction is conducted based on the following parameters: organic loading rate, removing efficiency of ammonia - nitrogen, and nitrification rate. By using pre-treatment seafood processing wastewater with a C/N ratio of 5-6, these parameters were determined through an operating biological reactor with F/M from 0.16 to 0.2g BOD5/g MLVSS.d. In terms of the performance of the model, when optimizing the nitrification process, the efficiency removal reaches 78.3-80.0% for BOD5 and 93.9-94.5% for NH4-N. After that, the nitrification process occurred after 30 minutes of reaction phase, reached its maximum rate after 2 hours with nitrification rate from 0.04 to 0.08 g Nox/g MLVSS.d and then maintained for about 1 hour. Moreover, for an optimal nitrification process, the alkaline consumption of the model should be in the range 7.05-7.18 mg CaCO3/mg N.

Nanoarchitectonics of porous carbon derived from urea-impregnated microporous triazine polymer in KOH activator for adsorptive removal of sulfonamides from water

A microporous covalent-organic polymer (triazine polymer, referred to as MCTP), was synthesized and subsequently carbonized, after loading urea and KOH (serving as an additional nitrogen source and activator, respectively), through high-temperature pyrolysis. This process resulted in materials named KUCDCs, which exhibited high porosity and a broader range of pore sizes compared to carbon materials produced without the addition of urea and KOH, referred to as CDC. KUCDCs, CDC, and commercially available activated carbon (AC) were evaluated for their ability to remove sulfonamide drugs, sulfamethoxazole (SMX) and sulfachlorpyridazine (SCP), from aqueous solution. Among these materials, KUCDC-800, which was carbonized at a temperature of 800 °C, demonstrated superior adsorption performances for sulfonamides, attributed to its high porosity, nitrogen content, and presence of surface oxygen groups. The adsorption capacities for SMX and SCP on KUCDC were notably higher than those on AC and MDC, with maximum capacities (Q0) of 619 and 554 mg/g for SMX and SCP, respectively. Notably, KUCDC-800 stands out as a recyclable adsorbent with the highest reported Q0 for SMX to date under near-neutral conditions. The exceptional performance of KUCDC in adsorbing SMX could be explained by its high porosity and surface functionalities for hydrogen bonding interactions with the adsorbate.

Plasticity of leaf functional traits and growth responses to disturbance among cutting cultivars of Cryptomeria japonica in southern Japan

ABSTRACT Cryptomeria japonica (Thunb. ex L. f.) D. Don is the most major plantation species in Japan, and cultivars have been developed and planted under variable environmental conditions across the country. Productivity of clonal plantations is influenced by the ability of the genotype to acclimate to edaphic- and geographic-scale variation in environmental conditions and disturbance regimes. Because all individuals are genetically identical in a clonal plantation, the trait differences among individuals represent phenotypic plasticity. Here, we investigated how phenotypic plasticity and response to disturbance vary among cutting cultivars of C. japonica. We compared tree height, leaf morphology, nitrogen content, and frequency/intensity of growth-release observed in tree rings after thinning and disturbance among six cutting cultivars in 45-year-old provenance trials in south-western Japan. Nitrogen use efficiency was higher in the site where maximum tree height (H max) was taller, while shoot mass per area (SMA) was larger in the site where H max was shorter. Cultivars that grew well had high leaf nitrogen content (N G) and showed more efficient nitrogen use with high nitrogen-resorption efficiency (NRE). Yabukuguri, an intermediate-growth cultivar, was characterized by large SMA and greater plasticity in SMA and tree height in response to topographical and regional variation, as well as greater intensity of growth-release in tree-ring series indicating growth resilience following disturbance. Our results provide guidelines for selecting cultivars with high acclimation potential and resilience to environmental perturbation, which is important for sustaining plantation forests in uncertain environmental conditions expected by future climate change.

Identification and optimization of the key growth parameters involved in carotenoids production of the marine microalga Pavlova gyrans

In this work, a multivariate analysis was carried out, using a Plackett–Burman (PB) design involving seventeen growth parameters, on carotenoids production of Pavlova gyrans (p < 0.10). Each assay was analysed regarding its content (mg g−1) of fucoxanthin (Fx), diatoxanthin, diadinoxanthin, β-carotene (βCar), α-carotene, and the sum of all carotenoids analysed individually (TCar). According to the statistical analysis, modified medium formulations were developed for the particular cases of Fx, βCar, and TCar. The study showed that Fx content was positively affected by nitrogen supplementation and lower light intensities. Higher concentrations of nitrogen and iron increased the final content of βCar as well. Similarly, salinity, light intensity, nitrogen, iron, and cobalt were identified as key factors in TCar production. The PB-based formulations showed significant improvements (p < 0.05) for TCar (11.794 mg g−1) and Fx (6.153 mg g−1) when compared to the control conditions (Walne’s medium—2.010 mg g−1). Furthermore, effective control of key variables (e.g., light intensity) throughout P. gyrans growth proved successful (p < 0.05), increasing the productivity of Fx (0.759 mg L−1 d−1) and TCar (1.615 mg L−1 d−1).

New insights into chicken processing wastewater treatment: the role of the microalgae Parachlorella kessleri on nitrogen removal

ABSTRACT Microalgal Technologies have recently been employed as an alternative treatment for high nitrogen content wastewater. Nitrogen is an essential nutrient for microalgae growth, and its presence in wastewater may be an alternative source to synthetic medium, contributing to a circular economy. This study aimed to investigate the effect of using Parachlorella kessleri cultivated in wastewater from the thermal processing of chicken meat. Experiments were performed to obtain the ideal sampling site, inoculum dosage, and contact time. P. kessleri had better growth in the sample from the settling basin. Nitrogen removal was 95% (0,15 mg TNK/107 cells) in 9 days, and the final nitrogen concentration was lower than 20 mg/L, and the nitrate concentration was lower than 1 mg/L. However, during the third cycle in the kinetic assay, there was a decline in the microalgae growth, occasioned by the accumulation of nitrite (38,4 mg/L) in the inside of the cell. The study demonstrated that nitrogen concentration is directly related to the cell growth of the algae. Parachlorella kessleri efficiently removed nitrogen from chicken meat thermal processing wastewater and is a potential option for tertiary treatment and valorisation of such effluent as a nitrogen source.

Effect of three alkaline impurities on the pressure of 1,2, 4-triazole pyrolysis gas

1,2,4-triazole is now widely used in the production of pesticides and medicine, and progress has been made in the application of materials. The structural characteristics of 1,2,4-triazole with high nitrogen content will cause it to the release of a large amount of gas when it occurs pyrolysis, which may have a certain impact on industrial production safety. In the industrial process, there will be some other impurities mixed into it, so the influence of these impurities on the 1,2,4-triazole pyrolysis gas is worth exploring. In this study, the adiabatic acceleration calorimeter was used to simulate the adiabatic conditions to study the pressure value of the gas generated by the pyrolysis of 1,2,4-triazole itself, and the influence of the addition of three basic impurities on the overall pyrolysis pressure value. Experiments show that these three impurities can affect the pressure value of pyrolysis gas in different degrees. The results can provide reference for the loss prevention and control of 1,2,4-triazole in industrial production.

A sustainable, zero-waste approach for production of biohydrogen from chicken manure slurry by hybrid recycling of digestate

This study provides a sustainable approach to produce biohydrogen through the long-term hydrogenic fermentation of chicken manure (CM) in a semi-continuous stirred tank reactor (CSTR) under different organic loading rates (OLRs). To ensure the zero-waste route and sustainability, the total digestate was mechanically separated into liquid and solid fractions. The solid digestate fraction was thermally treated to produce biochar, while the liquid digestate fraction was biologically treated through bioaugmentation with a novel heterotrophic nitrification-aerobic denitrification (HD-AN (bacterial strain (Alcaligenes sp. ME-1). The results showed that the high concentration of free ammonia nitrogen (FAN) contents of CM could inhibit methanogenesis and induce hydrogen production. The ORLs of 2.5, 3.5, 4.5, and 5.5 gVS/L.d imposed to the CSTR resulted in volumetric hydrogen production (VHP) of 643.3 ± 37, 908.8 ± 64.5, 1077.8 ± 95.17, and 1383.3 ± 156.8 mL/L.d, respectively. The microbial community structures indicated the long-term adaptation of hydrogen-producing bacteria and methanogenesis inhibition. The bioaugmentation process removed 83.3 % of total ammonia and 66.2 % of the chemical oxygen demand (COD) from the liquid digestate fraction. The characteristics of the biochar derived solid digestate is suitable for land applications as fertilizer. The hybrid approach combining biohydrogenation, pyrolysis, and bioaugmentation, maximizes the utilization of chicken manure slurry while conforming to the sustainable development goals.

Occurrence and maturation transformation of organic and inorganic nitrogen in the Lower Cambrian shelf–slope facies shale: Implications for overmature N2-rich shale reservoirs in Southern China

Thermogenic molecular nitrogen (N2) is one of the primary sources of high N2 content in overmature shale gas reservoirs. However, it remains uncertain whether N2 is released from organic or inorganic sources because the occurrence and thermal stability of different nitrogen species vary. This study investigates the Lower Cambrian shale samples from a well in southeastern Guizhou, China to determine the abundance, occurrence, and source of nitrogen in marine shale. A sealed gold tube pyrolysis experiment was further conducted on isolated kerogen and organic matter (OM)-ashed samples from one typical shale to explore the maturation transformation of organic nitrogen (Norg) and inorganic nitrogen (Ninorg). The results reveal that the studied shale exhibits a high nitrogen content, with the Norg content being less than that of Ninorg. The predominant functionality of Norg is pyrrolic-N, and Ninorg occurs primarily in silicates (NH4+-bearing illite and (NH4+, K, Ba)-feldspar). The structural characteristics of the different nitrogen functionalities cause them to vary in their thermal transformation behavior. The pyrolysis experiment results indicate that the nitrogen release of the shale increases rapidly when EqVRo >3.7%, and the N2 yields for typically shelf-slope facies shales are primarily 1–2 m3/t at EqVRo 4.0%–4.2%, to which the Ninorg has a dominant contribution. Further evidence that the high N2 shale gas reservoirs occur at EqVRo >3.5% is provided by compiled gas composition data from various risk wells. It is proposed that the Lower Cambrian shale gas exploration should address the considerably increased N2 risk in the shelf–slope facies area.

Synthesis and characterization of chitosan-modified membrane for urea slow-release fertilizers

BackgroundUrea is a fertilizer widely used by farmers, especially vegetable farmers, due to its high nitrogen content, around 46 %. However, plants only use a small amount of nitrogen, a maximum of 35 %, while the remaining nitrogen is wasted and released into the environment. Undeniably, it causes increases production costs and environmental problems. A slow-release urea fertilizer (SRF) has been formulated to resolve these issues. MethodsIn this study, the membrane was made of chitosan with several crosslinking agents such as Tripolyphosphate (TPP). In addition, calcium ion bonds are expected to increase the interaction with urea fertilizer through the encapsulation process. The resultsOur data showed that urea slow-release fertilizer (SRF) with the chitosan/TPP/Ca membrane, was successfully synthesized. This membrane has the characteristics of a thin white layer that is transparent. The physical and chemical characterization of SRF membranes with various coating membrane variations showed that the chitosan/TPP/Ca-urea membrane has Young's modulus of 7.75–22.05 N/mm2, swelling of 109.52–132.62 % and porosity of 0.756–1.06 %. Functional group analysis shows that several spectral changes indicate the presence of crosslinking process between the chitosan functional groups and TPP. The urea release results show that the membrane is released through a diffusion mechanism. Furthermore, SEM results show that these membranes have pores with various shapes and sizes. ConclusionBased on the result, it can be concluded that chitosan membrane modification with the addition of TPP and calcium oxide provides improved membrane characteristic cs including degree of development, hydrophobicity, membrane stress, and nitrogen release on the membrane. This membrane shows is indicating suitability as a slow-release fertilizer.

Role of phytoplankton composition on exudation of dissolved organic carbon in the Bay of Bengal

Phytoplankton in the marine environment exudates part of the primary production as dissolved organic carbon (DOC) into the surrounding waters. The rate of exudation of DOC is depended on the hydrographic condition, nutrient availability, phytoplankton composition, and their size structure. To examine this, samples were collected from the coastal and offshore regions where different hydrographic conditions exists in the Bay of Bengal. The coastal waters were relatively low saline, rich in inorganic nutrients, high phytoplankton biomass (Chl-a) and primary production in the coastal compared to offshore regions. The photic zone integrated Chl-a displayed insignificant difference between coastal and offshore regions whereas higher photic zone integrated primary production was observed in the former than latter region. Dominance of microplankton was observed in the coastal waters associating with high inorganic nitrogen concentrations, in contrast, picoplankton dominated in the offshore region associating with low inorganic nitrogen but high organic nitrogen concentrations. Due to high surface-to-volume ratio of picoplankton, ∼45% of the primary production exudated as DOC in the offshore compared to the coastal region (∼12%) due to dominance of microplankton. The sum of primary production and DOC exudation, called total primary production, was almost equal in the coastal and offshore regions. The mean phytoplankton biomass normalized primary production (pB) in the Bay of Bengal was low (17 ± 8 mgC mgChl-a−1 d−1) compared to Arabian Sea (37 ± 5 mgC mgChl-a−1 d−1). In contrast pB estimated based on total primary production is close (30 ± 16 mgC mgChla−1 d−1) to that of the Arabian Sea (37 ± 5 mgC mgChl-a−1 d−1) suggesting that the Bay of Bengal is equally productive compared to that of Arabian Sea than hitherto hypothesized due to strong stratification and less nutrients input in the former basin. The low sinking carbon flux observed below the photic zone is attributed to the release of primary production as DOC. The released DOC from the phytoplankton may support heterotrophic activity as evidenced by the existence of strong net heterotrophy in the Bay of Bengal. This may lead to the time lag between primary and export productions. None of these processes were incorporated into the numerical models resulting in inaccurate simulations of carbon cycling in the northern Indian Ocean. Modifications in the models by incorporating these processes may improve model simulations for a better understanding the modifications in biogeochemical processes due to climate change in the Bay of Bengal.

Polymethylenetetrazole: Synthesis, Characterization, and Energetic Properties.

The tetrazole moiety remains one of the most interesting scaffolds in the development of new high-energy density materials (HEDMs) because of its desired characteristics, such as high nitrogen content and heat of formation (HOF). The combination of several heterocycles with high HOF seems to be a promising strategy for obtaining energetic materials with superior properties. Herein, we report the synthesis and characterization of a tetrazole polymer, polymethylenetetrazole (PMT), as a potential HEDM. The compound was characterized using NMR, IR, and Raman spectroscopy. Its weight average molecular mass was obtained by static light scattering (SLS), and its physical properties by powder XRD analysis. The density, sensitivity to friction (FS), and impact (IS) of the compound were determined as well. The results of the thermal and energetic properties of PMT suggest that this polymer could be an insensitive explosive.

Unveiling the synergy of volatile fatty acids and ammonia nitrogen in optimizing methane production during dry anaerobic digestion of pig manure and corn straw

Dry anaerobic digestion (AD) is vulnerable to volatile fatty acids (VFA) and ammonia nitrogen. Understanding their synergy is crucial for optimizing strategies. In this study, the digestive performance, microbial dynamics, metabolic pathways, and synergistic relationships were investigated in the dry AD process by adding different concentrations of acetic acid (2, 5, and 8 mg/g) and urea (1, 5 mg/g N). Results showed that acid inhibition was caused by excessive pH reduction due to VFA accumulation. Propionic acid was the primary form of VFA accumulation. The inhibition of VFA accumulation could be alleviated using a low concentration of ammonia nitrogen (1 mg/g N urea) or be strengthened using a high concentration of ammonia nitrogen (5 mg/g N urea). Compared with the control group (82.2 mL/g VS), VFA and 1 mg/g N urea had a synergistic facilitation effect on the methane production (increasing by 1.7 %-18.1 %). This synergistic effect shortened the lag phases, enhanced the activity of Caldicoprobacter and Methanosarcina, increased the expression of genes encoding functional enzymes involved in the acetoclastic-methanogenic pathway. By contrast, VFA and 5 mg/g N urea had a synergistic inhibition effect on methane production (decreasing by 65.7 %–69.8 %). This synergistic effect prolonged lag phases, increased the relative abundance of ammonia-tolerant and acid-tolerant microbial (such as Methanoculleus) and reduced the expression of genes encoding functional enzymes involved in the hydrogenotrophic-methanogenic pathway. These results improve the understanding of methane regulation during dry AD.

Optimization of ammonia nitrogen benchmarks and ecological risk assessment in monsoon freezing lakes based on species sensitivity distribution with Lake Chagan in northeastern China as an example

There is an urgent need to determine reasonable water-quality benchmarks and risk assessment results to accurately characterize the relationship between crop yield enhancement and ammonia nitrogen pollution caused by excessive nitrogen fertilizer application. Through the collection of monitoring data from 2016 to 2023 in Chagan Lake, the first development of ecological criteria for ammonia nitrogen and risk evaluation for Northeast China was carried out based on the secondary ecological risk models (the quotient value method and joint probability curve). In addition, the species sensitivity distribution (SSD) model is improved through the use of genetic algorithms to identify more suitable ammonia water-quality benchmarks for ecological risk assessment. The results showed that high ammonia nitrogen concentration in wet season is primarily influenced by agricultural irrigation and drainage activities, whereas the dry season is driven by low temperatures and the nitrogen and phosphorus concentrations. The biological benchmark of improved SSD model with a genetic algorithm has a maximum error reduction of 23.84 % compared with other distributions, which is more than twice that of the median water-quality benchmark under the traditional Class III water-quality standard and empirical formula. Risk evaluation using traditional water-quality standards leads to the overprotection of the biological environment. Evaluations using quotient value methods and joint probability curves yield consistent results. The severity of the ecological risk of ammonia nitrogen follows the order: wet season > flat season > dry season. Using a genetic algorithm to optimize SSD model can effectively reduce the uncertainty of the model, providing a more accurate and reasonable ammonia nitrogen water-quality benchmark. This study improves the evaluation of the ecological risk of ammonia nitrogen in Lake Chagan, provides ideas for reducing the uncertainty of the selection of ammonia nitrogen water-quality benchmarks, and effectively prevents the overprotection of the lake from ammonia nitrogen.

Environmental and genetic drivers of physiological and functional traits in a key canopy species

The resilience of forests worldwide is challenged by climate change. Large-scale tree mortality and dieback events have been documented across continents in recent decades. The adaptive capacity of forests is important for predicting forest resistance and resilience to future climates yet remains largely unknown. We grew 12 populations of a widespread foundation tree species (Corymbia calophylla), originating from different temperature and rainfall regimes, in two common garden trials in Western Australia that had similar temperature but contrasting rainfall conditions. We quantified intraspecific trait variation at these two sites to estimate genetically determined trait variation with climate origin (genetic adaptation) and trait variation associated with environment (phenotypic plasticity). We aimed to determine the 1) contribution of genetic and environmental factors on growth, functional, and physiological trait variation; 2) coordination of leaf traits within the context of the leaf economic spectrum (LES) in variable rainfall conditions; and 3) role of local or regional climate adaptation influencing tree growth and water use efficiency. Growth and physiological traits were differentially expressed across populations and sites, highlighting the importance of genetic adaptation and phenotypic plasticity. Leaf traits reflected a more water conservative strategy with higher water use efficiency, high foliar nitrogen content, and low specific leaf area, as predicted by the LES, in trees at the dry site measured in autumn after the warm summer. Local adaptation was detected in growth and leaf water use efficiency traits at the regional climate, not the local population, scale. Plants from the cool region had greater performance than those from the warm region in most plant traits. Home-site rainfall was not a good predictor of trait expression. The capacity of C. calophylla to respond to low water availability through genetic adaptation and phenotypic plasticity may enable it to maintain optimal performance in drier conditions associated with climate change.

Fischer-Tropsch Synthesis for the Production of Sustainable Aviation Fuel: Formation of Tertiary Amines from Ammonia Contaminants.

Fischer-Tropsch synthesis combined with product workup is a promising route toward synthetic aviation fuel from renewable hydrogen and carbon sources like biomass, CO2, and waste. Cost savings can be achieved by reducing the number of gas treatment steps in new plants, but the consequence of contaminants in the feed needs investigation. While feeding 2.6 ppmV ammonia to a Fischer-Tropsch reactor, it was shown that ammonia was predominantly chemically converted into organic amines, with most nitrogen found in the water phase (89%), followed by heavy wax (7%) and light wax (1%). The concentration difference between water and light wax was shown to be due to the post-condensation separation of amines on polarity. Amines up to a chain length of 120 were detected in the heavy wax with MALDI-FT-ICR-MS, which, in combination with the high nitrogen content, suggests that amines have a similar chain growth probability compared to the main hydrocarbon products. Detailed product analysis with three independent analytical techniques showed that tertiary N,N-dimethylalkylamines were by far the most abundant amine class. This suggests that ammonia is decomposed on the cobalt surface and, potentially as a dimethylamine fragment, incorporated in the growing chain. Further evidence was obtained from the abundance of trimethylamine and from the reconciled nitrogen product analysis up to C100, which showed that the amine product distribution followed from naphtha onward the same ASF kinetics as alkanes and oxygenates while being distinctively different from the alkene distribution. The presented findings provide further avenues for studies of the Fischer-Tropsch reaction mechanism and indicate the opportunity of cost saving on gas treatment, while further validation is required to assess the impact on hydrocracking and product quality.

Functional guanine superstructures derived superior sodiophilic porous carbonaceous metamaterial for anodic-sodium-metal-free sodium metal batteries

Metamaterials, owing to their engineered building blocks, are considered as easily functionalized composites with designed nano-properties, sparking widespread research interest. However, the scalable synthesis and programmatically derived metamaterials into the designed nano-to-macro functionalized structure still pose significant challenges. Here, we report a fast and scalable synthesized Sn-guanine superstructures derived 1D porous carbonaceous metamaterial frameworks (Sn-NCS) that self-assembled by atomic Sn doping high nitrogen content carbon nanosheets. Due to the unique bottom-up designed nano-to-macro functionalized structural characteristics, Sn-NCS exhibited superior sodiophilic property. Using density functional theory (DFT) analysis and in-situ/ex-situ experimental characterization, we reveal that Sn-NCS can not only provide abundant Sn-N4 functional sites to minimize sodium nucleation overpotential and favors a uniform Na nucleation, but also effectively guide sodium deposition within the self-assembled porosity framework of Sn-NCS along the surface of carbon nanosheets to accommodate the volume variation and stress fluctuations within the anode, even under the extremely high current density of 120 mA/cm2 with a deposition/stripping capacity of 20 mAh/cm2. Moreover, the fabricated anode-sodium-metal-free sodium metal batteries (ASM-free SMB), using Cu-Sn-NCS (Sn-NCS coated Cu foil with a mass loading of 0.1 mg/cm2) as anodic current collector, exhibit highlighted energy density and excellent cycling reliability.

Phosphate limitation enhances malic acid production on nitrogen-rich molasses with Ustilago trichophora

BackgroundAn important step in replacing petrochemical products with sustainable, cost-effective alternatives is the use of feedstocks other than, e.g., pure glucose in the fermentative production of platform chemicals. Ustilaginaceae offer the advantages of a wide substrate spectrum and naturally produce a versatile range of value-added compounds under nitrogen limitation. A promising candidate is the dicarboxylic acid malic acid, which may be applied as an acidulant in the food industry, a chelating agent in pharmaceuticals, or in biobased polymer production. However, fermentable residue streams from the food and agricultural industry with high nitrogen content, e.g., sugar beet molasses, are unsuited for processes with Ustilaginaceae, as they result in low product yields due to high biomass and low product formation.ResultsThis study uncovers challenges in evaluating complex feedstock applicability for microbial production processes, highlighting the role of secondary substrate limitations, internal storage molecules, and incomplete assimilation of these substrates. A microliter-scale screening method with online monitoring of microbial respiration was developed using malic acid production with Ustilago trichophora on molasses as an application example. Investigation into nitrogen, phosphate, sulphate, and magnesium limitations on a defined minimal medium demonstrated successful malic acid production under nitrogen and phosphate limitation. Furthermore, a reduction of nitrogen and phosphate in the elemental composition of U. trichophora was revealed under the respective secondary substrate limitation. These adaptive changes in combination with the intricate metabolic response hinder mathematical prediction of product formation and make the presented screening methodology for complex feedstocks imperative. In the next step, the screening was transferred to a molasses-based complex medium. It was determined that the organism assimilated only 25% and 50% of the elemental nitrogen and phosphorus present in molasses, respectively. Due to the overall low content of bioavailable phosphorus in molasses, the replacement of the state-of-the-art nitrogen limitation was shown to increase malic acid production by 65%.ConclusionThe identification of phosphate as a superior secondary substrate limitation for enhanced malic acid production opens up new opportunities for the effective utilization of molasses as a more sustainable and cost-effective substrate than, e.g., pure glucose for biobased platform chemical production.

Investigation of optimum conditions for the recovery of magnesium ammonium phosphate from human urine using the Box–Behnken design

ABSTRACT Urine from domestic wastewater greatly increases the nutritional value of wastewater. Urine has a high concentration of nutrients and minerals that can be utilized as plant growth agents, according to a chemical analysis. Due to its high phosphate, nitrogen, and potassium content, human urine can serve as a sustainable substitute for chemical fertilizers. Struvite, also referred to as MAP, can be considered as a sustainable fertilizer and it is a magnesium ammonium phosphate crystal with the chemical formula of MgNH4PO4·6H2O. Struvite may be formed from many types of wastewater, one inexpensive and reliable source for struvite formation being human urine. However, struvite formation requires an external magnesium supply due to the extremely low concentration of magnesium in human urine. In this work, magnesium ammonium phosphate was precipitated from human urine by examining the effects of Mg2+ dose, temperature, and pH on struvite crystals. Several experiments for struvite precipitation were created using the Box–Behnken design. Struvite crystals formed upon the addition of a magnesium source at 20 °C, pH 10, and a mole ratio of 1:1. The results show that the large-scale application and nutrient recovery of struvite crystals from human urine are promising.

Insights into the oxidative thermal stability of mesoporous triazine‐based organic polymers: Kinetics and thermodynamic parameters

AbstractThis study investigates the thermal degradation kinetics of mesoporous triazine‐based polymers, namely triazine‐amine and triazine‐ether polymers. The synthesis, physicochemical characterization, and catalytic applications of these polymers were discussed in our previous report. Herein, the thermal stability parameters, including kinetic triplets and thermodynamic parameters, were determined using thermogravimetric analysis (TGA) and non‐isothermal mathematical approximations such as Coats‐Redfern, Broido, and Horowitz–Metzger methods. Triazine‐ether polymers exhibit thermal stability within the range of 200°C–300°C, while triazine‐amine polymer demonstrates superior thermal stability, reaching up to 450°C. According to the Coats‐Redfern method, the degradation follows reaction orders of 0.5 ≤ n ≤ 1. The activation energy of triazine‐amine polymer is notably high, particularly at the third degradation stage (e.g., 89.0 kJ/mol by the Broido method), attributed to its high nitrogen content. Conversely, the higher carbon content of triazine‐ether polymers reduces their activation energy to approximately 30 kJ/mol at all stages and thus, facilitates the degradation process. Thermodynamically, the degradation process is favorable yet non‐spontaneous, with intermediate states of the polymers exhibiting higher entropy, indicative of their enhanced degradation capability.

Hybrid Biopellets Characterization of Gamal Wood (Gliricidia sepium) and Robusta Coffee Husk at Various Compositions

Biopellets from gamal wood (Gliricidia sepium) as a biomass energy resource could be an alternative to replace fossil fuels due to having met standards based on moisture content, ash content, fixed carbon, calorific value, and density. Unfortunately, they still had high levels of volatile matter. Robusta coffee husk was a material with high nitrogen content, which is suspected of being able to bind aromatic substances in volatile organic compounds. This study aims to evaluate the quality of biopellets and determine the optimum composition of the biopellets from gamal wood and coffee husk. The blended composition of gamal wood and coffee husk biopellets studied were 100:0, 75:25, 50:50, 25:75, and 0:100. The biopellets were manufactured using the material size of 40-60 mesh with a pressure of 173.51 MPa. The best biopellet was produced in the composition of 75% gamal wood and 25% coffee husk, with a density of 0.85 g/cm3, moisture content of 8.03%, ash content of 3.92%, volatile substances of 78.01%, fixed carbon of 18.07%, and calorific value of 4,176 cal/g. The biopellet quality met the standards of SNI 8021:2014 and EN 14061-2, except for ash content. Adding coffee husk reduced gamal wood biopellet’s volatile matter, increasing the fixed carbon and density of gamal wood biopellets. Keywords: alkali immersion, bamboo, bio-composite, oriented strand board, pre-treatment