Carbon Compounds Research Articles

Reaction rebalancing: a novel approach to curating reaction databases

PurposeReaction databases are a key resource for a wide variety of applications in computational chemistry and biochemistry, including Computer-aided Synthesis Planning (CASP) and the large-scale analysis of metabolic networks. The full potential of these resources can only be realized if datasets are accurate and complete. Missing co-reactants and co-products, i.e., unbalanced reactions, however, are the rule rather than the exception. The curation and correction of such incomplete entries is thus an urgent need.MethodsThe SynRBL framework addresses this issue with a dual-strategy: a rule-based method for non-carbon compounds, using atomic symbols and counts for prediction, alongside a Maximum Common Subgraph (MCS)-based technique for carbon compounds, aimed at aligning reactants and products to infer missing entities.ResultsThe rule-based method exceeded 99% accuracy, while MCS-based accuracy varied from 81.19 to 99.33%, depending on reaction properties. Furthermore, an applicability domain and a machine learning scoring function were devised to quantify prediction confidence. The overall efficacy of this framework was delineated through its success rate and accuracy metrics, which spanned from 89.83 to 99.75% and 90.85 to 99.05%, respectively.ConclusionThe SynRBL framework offers a novel solution for recalibrating chemical reactions, significantly enhancing reaction completeness. With rigorous validation, it achieved groundbreaking accuracy in reaction rebalancing. This sets the stage for future improvement in particular of atom-atom mapping techniques as well as of downstream tasks such as automated synthesis planning.Scientific ContributionSynRBL features a novel computational approach to correcting unbalanced entries in chemical reaction databases. By combining heuristic rules for inferring non-carbon compounds and common subgraph searches to address carbon unbalance, SynRBL successfully addresses most instances of this problem, which affects the majority of data in most large-scale resources. Compared to alternative solutions, SynRBL achieves a dramatic increase in both success rate and accurary, and provides the first freely available open source solution for this problem.

Contributions of Different Perennial Grass Species and Their Roots’ Characteristics to Soil Organic Carbon Accumulation

Growing perennial grasses is often cited as one of the possible and most affordable solutions for mitigating climate change. This practice is also recommended for sustainable soil management in agriculture. Our experiment involved timothy grass (Phleum pratense L.), red clover (Trifolium pratense L.), and their mixture; tall oat grass (Arrhenatherum elatius L.), alfalfa (Medicago sativa L.), and their mixture, with the aim of diversifying the annual rotation; and periodical, twice-per-season cultivated plots in the same area (the bare soil fallow). Soil samples were collected in late October after plant vegetation’s first, second, and third growth years from three field replicates at the soil layers 0–0.1 m, 0.1–0.2 m, and 0.2–0.3 m and plant roots—at the beginning of November in the second cultivation year. After three years, the SOC content increased in all the study areas occupied by plants, regardless of their species composition, while it decreased in fallow plots. Grass roots were characterized by the highest C/N ratio (38.2 and 45.5). The roots of the red clover–timothy grass mixture also reached a C/N ratio greater than 30. Based on our research, choosing a combination of at least two plants, such as legumes and grasses, is possibly more effective for enriching the soil with carbon compounds in a short period.

Responses of soil organic carbon compounds to phosphorus addition between tropical monoculture and multispecies forests

Tropical forests are sensitive to nitrogen (N) and phosphorus (P) availability, and under nutrient application the variation of soil organic carbon (SOC) preserving mechanism remains to be explored. To reveal the forest-specific SOC preservation via biochemical selection in response to nutrient application, we investigated a monoculture (Acacia plantation) and a multispecies forest both with chronic fertilization in subtropical regions, and measured specific fingerprints of plant- and microbial-derived C compounds. In addition, to quantify the effect of P application on SOC content among tropical forests, we conducted a meta-analysis by compiling 125 paired measurements in field experiments from 62 studies. In our field experiment, microbial community composition and activity mediated forest-specific responses of SOC compounds to P addition. The shift of community composition from fungi towards Gram-positive bacteria in the Acacia plantation by P addition led to the consumption of microbial residual C (MRC) as C source; in comparison, P addition increased plant species with less complex lignin substrates and induced microbial acquisition for N sources, thus stimulated the decomposition of both plant- and microbial-derived C. Same with our field experiment, bulk SOC content had neutral response to P addition among tropical forests in the meta-analysis, although divergences could happen among experimental durations and secondary tree species. Close associations among SOC compounds with biotic origins and mineral associated organic C (MAOC) in the multispecies forest suggested contributions of both plant- and microbial-derive C to SOC stability. Regarding that fungal MRC closely associated with MAOC and consisted of soil N pool which tightly coupled to SOC pool, the reduce of fungal MRC by chronic P addition was detrimental to SOC accumulation and stability in tropical forests.

Candida parapsilosis CMGB-YT Biosurfactant for Treatment of Heavy Metal- and Microbial-Contaminated Wastewater

During the last few decades, water pollution has become a growing concern at international level. To date, only a few Candida parapsilosis strains were successfully used in environmental remediation. In the present article, the strain C. parapsilosis CMGB-YT was studied for its ability to assimilate hydrophobic substrates and to produce biosurfactants with antimicrobial activity and positive effects on heavy metal removal from contaminated wastewaters. The strain C. parapsilosis CMGB-YT was grown on yeast peptone (YP) media with 1% n-decane, n-dodecane, n-tetradecane, n-hexadecane, as well as commercial sunflower and olive oils. The production of the biosurfactant was evaluated using the emulsification index (E24%). The surface properties and emulsifying stability of the biosurfactant were determined. The effect of the biosurfactant on the cell growth of two strains of Rhodotorula mucilaginosa and on their removal capacity of lead (0.032 g/L) and cadmium (0.030 g/L) ions from synthetic wastewater were also studied. The antimicrobial potential of 20 mg/mL and 40 mg/mL biosurfactant was established in the presence of pathogenic Candida krusei strains. C. parapsilosis CMGB-YT assimilated n-hexadecane with good rates over 216 h and produced an anionic glycolipidic biosurfactant with stable E24% towards long-chain carbon compounds at different temperatures, with an alkaline pH and high salinity (10% NaCl). The biosurfactant reduced the surface tension to 53.58 ± 0.42 mN/m, while the critical micellar concentration (CMC) was reached at 4.2% biosurfactant. The crude biosurfactant (5%) enhanced R. mucilaginosa growth in heavy metal-contaminated wastewater, increased chemical oxygen demand (COD) removal of up to 80%, and improved Cd²⁺ removal by 10%. Additionally, the concentrated biosurfactant effectively prevented Candida krusei biofilm formation. In conclusion, the biosurfactant produced by C. parapsilosis CMGB-YT demonstrates promising potential for the efficient treatment of wastewater contaminated with heavy metals and microbial pathogens.

Gas-phase hydrogenation processes of cationic carbon clusters

ABSTRACT In this work, the gas-phase ion–atom collision reaction between large cationic carbon clusters and H-atoms is investigated. The carbon cluster cations (C$_{48-2*n}$$^+$, n = [0$-$8]) are produced from the photo-fragmentation processes of large PAH (dicoronylene, DC, C$_{48}$H$_{20}$) cations. The hydrogenated carbon cluster cations are efficiently formed (e.g. C$_{44/46}$H$_{9}$$^+$), and no even–odd hydrogenated mass patterns are observed. The hydrogenation behaviour and hydrogenation rate for these carbon cluster cations are the same. With theoretical calculations, the formation and bending processes of carbon cluster cations, the structure of these newly formed hydrogenated carbon cluster cations, and the bonding energies for the hydrogenation pathways are investigated. During the formation process of carbon clusters, the zigzagged edges gradually increase, and the planar configuration tends towards a bent and folded molecular configuration, i.e. from graphene to fullerene structures. The bending process with higher exothermic energies provides a reasonable explanation for the formation of the ‘magic numbers’ (e.g. C-atoms = 44) carbon clusters and their greater stability. The exothermic energy for each hydrogenation reaction pathway is relatively high; consequently, the forms and the hydrogenated states of carbon clusters are complex. The hydrogenation ability of edge carbon sites is higher than that of internal carbon sites; after bending and folding, the hydrogenation ability of these originally internal carbon sites becomes higher due to structural caged. As a result, under the co-evolution interstellar chemistry network, the (hydrogenation) states and forms of carbon compounds are complicated and diverse in the ISM.

Reasons why life on Earth rarely makes fluorine-containing compounds and their implications for the search for life beyond Earth

Life on Earth is known to rarely make fluorinated carbon compounds, as compared to other halocarbons. We quantify this rarity, based on our exhaustive natural products database curated from available literature. We build on explanations for the scarcity of fluorine chemistry in life on Earth, namely that the exclusion of the C–F bond stems from the unique physico-chemical properties of fluorine, predominantly its extreme electronegativity and strong hydration shell. We further show that the C–F bond is very hard to synthesize and when it is made by life its potential biological functions can be readily provided by alternative functional groups that are much less costly to incorporate into existing biochemistry. As a result, the overall evolutionary cost-to-benefit balance of incorporation of the C–F bond into the chemical repertoire of life is not favorable. We argue that the limitations of organofluorine chemistry are likely universal in that they do not exclusively apply to specifics of Earth’s biochemistry. C–F bonds, therefore, will be rare in life beyond Earth no matter its chemical makeup.

Analyzing Carbon-13 NMR Spectra to Predict Chemical Shifts of Carbon Compounds using Machine Learning Algorithms

Analyzing Carbon-13 NMR Spectra to Predict Chemical Shifts of Carbon Compounds using Machine Learning Algorithms

Sediment microbial communities of a technogenic saline-alkaline reservoir

Various natural saline and alkaline habitats have recently been widely investigated, but knowledge of anthropogenic habitats with more complex environmental conditions is still lacking. This research looks at the structure of microbial communities in 18 bottom sediment samples from a technogenic water body with saline and alkaline composition. The core samples were collected from 2 columns in the western and eastern parts of an artificial water body at the Verkhnekamskoe Salt Deposit (Russia). The microbial community structure was studied using high-throughput 16S rRNA gene sequencing. The bottom sediment composition (salinity, pH, and toxic element content) varies greatly with depth and laterally throughout the study area. The study found a considerable difference in bacterial community diversity between the 2 columns, but no considerable difference was found between the communities at various depths of the studied layers. Proteobacteria, Firmicutes, and Actinobacteria, which are common in both natural and artificial saline and alkaline environments, make up the majority of the bacteria found in the samples. Studies have shown that salinity and total alkalinity are the key factors influencing the formation of microbial communities. Ralstonia and Pseudomonas were the two most common genera in the sediment samples. These two genera are known for having high metabolic flexibility, which means they can survive in extreme environments and use a variety of carbon compounds as energy sources. The study also found that Ralstonia is indicator bacteria in samples with the highest concentrations of toxic elements compared to the other samples. A relatively high microbial diversity was discovered in the studied anthropogenic water reservoir despite the extreme alkaline and saline conditions, but it is considerably lower than that found in natural, less alkaline habitats. This research offers insight into the mechanisms behind microbial community formation in complex anthropogenic environments and covers key factors in microbial community distribution.

Exploring the Influence of Natural and Agricultural Land Use Systems on the Different Lability Organic Carbon Compounds in Eutric Endocalcaric Arenosol

It is important to ensure the ratio of stable and labile soil organic carbon (SOC) compounds in the soil as this influences ecosystem functions and the sustainability of soil management. The aim of this investigation was to determine the changes in SOC compounds and soil quality improvement in Arenosol soil after the conversion of arable land to natural and agricultural land use. The land use types included pine afforestation (PA), uncultivated abandoned land (UAL), unfertilised and fertilised cropland (CLunf, CLf), and unfertilised and fertilised grassland (GRunf, GRf). To assess the lability of organic carbon (OC) compounds, levels of mobile humic substances (MHSs), mobile humic acids (MHAs), mobile fulvic acids (MFAs), active C pool (POXC), and water-soluble C (WEOC) compounds were determined. It was found that faster OC accumulation occurs in PA soil than in CLf, and is somewhat slower in grassland uses (GRf and UAL). As the amount of SOC increased, more MHS formed. A significant increase in their quantity was found in PA (+92.2%) and CRf and UAL (+51.5–52.7%). The application of mineral fertilisers promoted the formation of MHSs in CLf and GRf. PA, GRunf, and GRf soils had more suitable conditions for MHA formation (MHA/MFA > 1.3), whereas CLunf soil contained more MFAs. The POXC pool was insensitive to land-use changes in the Arenosol. After land-use conversion, POXC amounts were significantly (p < 0.05) higher in natural ecosystems (UAL and PA) and fertiliser perennial grasses than in CL. The amount of WEOC increased the most in UAL, PA, and GRf (7.4–71.1%). The sequence of decrease in land use was GRf, UAL, and PA > CLunf, CLf, and GRunf. The decreasing order of the carbon management index (CMI) of different land uses (PA > UAL > GRf > GRunf > Clunf) confirms that faster OC accumulation in Arenosol soil occurred in PA and grassland land uses (GRf and UAL). The values of the carbon lability index (CLI) variation (CLunf > GRunf GRf > UAL > PA) show that in PA, UAL, and GRf land uses, mobile organic matter (OM) forms are relatively less formed, which stabilises OC accumulation in the soil. The CMI showed that UAL and GRf were the most suitable soil uses for Arenosol soils.

Efficient biological treatment: Achieving exceptional reductions in pollutants and ensuring environmental compliance

The study assessed the effectiveness of treatment processes in removing organic matter, biogenic compounds and suspended solids at the subsequent treatment stages one of the Polish municipal wastewater treatment plant. In a comprehensive mechanical-biological treatment, for all tested pollution indicators, i.e. biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and total suspended solids (TSS), outstanding results, surpassing regulatory standards, were obtained. The achieved average percentage reduction was from 87 % for TN (standard deviation of 2.7 %) to average 99 % for BOD5 (standard deviation of 0.3 %). The observed average BOD5/COD ratio of 0.45 aligned with typical values reported, and the decrease in the ratio to 0.13 after biological treatment underscored the efficacy of these processes in organic compounds decomposition and managing difficult-to-degrade substances. The BOD5/TN values emphasized the effectiveness of the treatment, maintaining well-balanced proportions between organic carbon and nitrogen compounds. Moreover, raw sewage showed notable susceptibility to nitrogen removal, indicated by the highest average BOD5/TN ratio of 6.72, suggesting a high propensity for biodegradation. This study highlighted that the average BOD5/TP value of 56 in raw sewage indicated a significant susceptibility to phosphorus compound removal. The treated sewage consistently adhered to environmental regulations, demonstrating minimal variability in pollution indicators. That underscored the effectiveness of treatment processes in meeting stringent standards and achieving significant reductions in pollutants. Effective sewage treatment is even more significant, because it is possible to reuse treated sewage e.g. for irrigation in agriculture, what contributes to the sustainable water management.

Comparative Analysis of CO2 Emissions, Fuel Consumption, and Fuel Costs of Diesel and Hybrid Dredger Ship Engines

There is a consensus on the need to reduce the emissions of carbon compounds. The increase in global greenhouse gas (GHG) emissions in the maritime industry poses a serious challenge to environmental sustainability, climate change, and the operating costs of ships. This article shows how hybrid versus diesel propulsion technology for ships can help reduce carbon dioxide (CO2) emissions and fuel consumption, and how these changes can be achieved. The need to reduce exhaust emissions and the increasing need for the shipping industry to seek alternative fuels means that existing regulations for marine engines and engine emissions are being updated almost constantly and new regulations are being formulated. The cost implications of the new regulations may lead to an increase in emissions as engines with lower fuel consumption are chosen, i.e., larger marine engines. Alternative approaches are needed to reduce CO2 emissions and fuel consumption, which could ultimately lead to hybrid propulsion for ships. This paper examines the current state of greenhouse gas emissions in shipping by analyzing the CO2 emissions and operating costs of two ships of the same type with similar technical and technological characteristics and different propulsion systems to gain insight into the problem. This paper compares the reductions in CO2 emissions, fuel consumption, and fuel costs for two suction hopper dredgers with standard diesel and hybrid propulsion. The technical characteristics, CO2 emissions, fuel consumption, and price of the two ships were analyzed to determine the advantages and disadvantages of each propulsion system. The novelty of this study is that two suction hopper dredgers from the same company with similar technical–technological characteristics but different propulsion systems were used for the case study and a mathematical procedure for calculating CO2 and other greenhouse gasses was presented in comparison, all to determine to what extent and in what way the hybrid propulsion system of a ship can contribute to reductions in CO2 emissions and fuel costs at the ship and company levels compared to a standard diesel propulsion system. This comparative analysis shows how much lower CO2 emissions, fuel consumption, and fuel cost savings can be expected when using a hybrid propulsion system compared to a standard diesel propulsion system. Finally, a conclusion is drawn on the efficiency and environmental compatibility of the two systems.

Clusters of composition: Elemental content of aquatic organic matter in UK and Faroe peatlands

Water supply companies with reservoirs in peatland areas need to know how land use and vegetation cover in their supply catchments impact the amount and composition of aquatic organic matter in raw waters. Drinking water treatment processes remove organic matter from potable supplies, but recent increases in concentration and changes in composition have made this more difficult. This study analysed the composition of aquatic organic matter from peatland catchments in the UK and Faroe Islands. Both dissolved organic matter (DOM) and particulate organic matter (POM) compositions varied spatially, but these differences were not consistent as water moved through catchments, from headwaters and peatland pools to lake and reservoir outlets. These data showed that lakes and reservoirs are acting as flocculation hotspots, processing OM, releasing carbon (C), hydrogen (H) and oxygen (O) compounds to the atmosphere, and resulting in OM with higher N content. DOM compositions could be grouped into five clusters, showing that water treatment processes can be maximised to target ‘envelopes’ or clusters of DOM compositions. Catchment factors such as land use, vegetation cover, percentage peat cover and catchment area are good indicators of OM compositions likely to be present in a reservoir, and can guide water companies to maximise efficiency of their raw water treatment processes.

Foundry by-products: Alternative materials for ceramic tiles. Technical, radiological and environmental assessment

The aim of this study is to assess the feasibility of using foundry by-products in porcelain tiles. This feasibility has been evaluated by three different perspectives: technical, radiological and environmental. Firstly, given that the main impurities in foundry by-products are carbon and organic compounds, thermal treatments that successfully reduce carbon and organic compounds have been evaluated. Subsequently, both calcined and uncalcined by-products have been characterised from a technological and radiological point of view and finally, porcelain tile compositions with both calcined and uncalcined by-products have been obtained. These compositions were fully characterised and their performance in the manufacturing process has been evaluated. The environmental impacts of this recycling process were also assessed by means of a life cycle assessment. The results confirm that foundry by-products can partially replace sand in porcelain tile bodies.

Molecular-level carbon traits of fine roots: unveiling adaptation and decomposition under flooded conditions

Abstract. Fine roots are vital for plant development and carbon biogeochemical cycling in terrestrial ecosystems. Flooding is known to regulate the physiology and morphology in plant roots; however, its impact on molecular-level characteristics of carbon compounds (carbon traits) in fine roots remains largely unexplored, which limits our understanding of root adaptation and decomposition under changing environments. Here, we used a sequential extraction method, starting from nonpolar to polar solvents, in order to obtain dichloromethane- and methanol-extractable (FDcMe) fractions, base-hydrolyzable (FKOHhy) fractions, and CuO-oxidizable (FCuOox) fractions from fine roots of Dysoxylum binectariferum, which is naturally grown in soil and water. Subsequently, we characterized them using targeted gas chromatography–mass spectrometry and nontargeted Fourier transform ion cyclotron resonance mass spectrometry. Also, decomposition experiments were conducted on soil- and water-grown roots under aerobic and anoxic conditions. Results showed a consistent increase in the unsaturation degree and aromaticity of the analytes from FDcMe to FCuOox fractions. Both analyses were sufficiently sensitive to show that, compared to soil-grown roots, the water-grown roots developed more polyphenolics with a high unsaturation degree and aromaticity and had more nonstructural compositions. Furthermore, although flooding provided an anoxic condition that slowed down root decomposition, the adaptive strategy of developing more nonstructural labile components in water-grown roots accelerated root decomposition, thereby counteracting the effects of anoxia. This advances our understanding of biogeochemical processes in response to global environmental change.

Wildfire smoke impacts lake ecosystems.

Wildfire activity is increasing globally. The resulting smoke plumes can travel hundreds to thousands of kilometers, reflecting or scattering sunlight and depositing particles within ecosystems. Several key physical, chemical, and biological processes in lakes are controlled by factors affected by smoke. The spatial and temporal scales of lake exposure to smoke are extensive and under-recognized. We introduce the concept of the lake smoke-day, or the number of days any given lake is exposed to smoke in any given fire season, and quantify the total lake smoke-day exposure in North America from 2019 to 2021. Because smoke can be transported at continental to intercontinental scales, even regions that may not typically experience direct burning of landscapes by wildfire are at risk of smoke exposure. We found that 99.3% of North America was covered by smoke, affecting a total of 1,333,687 lakes ≥10 ha. An incredible 98.9% of lakes experienced at least 10 smoke-days a year, with 89.6% of lakes receiving over 30 lake smoke-days, and lakes in some regions experiencing up to 4 months of cumulative smoke-days. Herein we review the mechanisms through which smoke and ash can affect lakes by altering the amount and spectral composition of incoming solar radiation and depositing carbon, nutrients, or toxic compounds that could alter chemical conditions and impact biota. We develop a conceptual framework that synthesizes known and theoretical impacts of smoke on lakes to guide future research. Finally, we identify emerging research priorities that can help us better understand how lakes will be affected by smoke as wildfire activity increases due to climate change and other anthropogenic activities.

Relaxation of Spring Festival Firework Regulations Leads to a Deterioration in Air Quality.

The relaxation of restrictions on Chinese Spring Festival (SF) firework displays in certain regions has raised concerns due to intensive emissions exacerbating air quality deterioration. To evaluate the impacts of fireworks on air quality, a comparative investigation was conducted in a city between 2022 (restricted fireworks) and 2023 SF (unrestricted), utilizing high time-resolution field observations of particle chemical components and air quality model simulations. We observed two severe PM2.5 pollution episodes primarily triggered by firework emissions and exacerbated by static meteorology (contributing approximately 30%) during 2023 SF, contrasting with its absence in 2022. During firework displays, freshly emitted particles containing more primary inorganics (such as chloride and metals like Al, Mg, and Ba), elemental carbon, and organic compounds (including polycyclic aromatic hydrocarbons) were predominant; subsequently, aged particles with more secondary components became prevalent and continued to worsen air quality. The primary emissions from fireworks constituted 54% of the observed high PM2.5 during the displays, contributing a peak hourly PM2.5 concentration of 188 μg/m3 and representing over 70% of the ambient PM2.5. This study underscores that caution should be exercised when igniting substantial fireworks under stable meteorological conditions, considering both the primary and potential secondary effects.

Effect of Land Use Change on Molecular Composition and Concentration of Organic Matter in an Oxisol.

Land use change from native vegetation to cropping can significantly affect the quantity and quality of soil organic matter (SOM). However, it remains unclear how the chemical composition of SOM is affected by such changes. This study employed a sequential chemical extraction to partition SOM from an Oxisol into several distinct fractions: water-soluble fractions (ultrapure water (W)), organometal complexes (sodium pyrophosphate (PP)), short-range ordered (SRO) oxides (hydroxylamine-HCl (HH)), and well-crystalline oxides (dithionite-HCl (DH)). Coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), the impact of land use change on the molecular composition of different OM fractions was investigated. Greater amounts of OM were observed in the PP and HH fractions compared to other fractions, highlighting their importance in SOM stabilization. The composition of different OM fractions varied based on extracted phases, with lignin-like and tannin-like compounds being prevalent in the PP and HH fractions, while aliphatic-like compounds dominated in the DH fraction. Despite changes in the concentration of each OM fraction from native vegetation to cropping, there was little influence of land use change on the molecular composition of OM associated with different mineral phases. No significant selective loss or preservation of organic carbon compounds was observed, indicating the composition of SOM remained unchanged.

Prospective Roles of Extremophilic Fungi in Climate Change Mitigation Strategies.

Climate change and the resultant environmental deterioration signify one of the most challenging problems facing humankind in the 21st century. The origins of climate change are multifaceted and rooted in anthropogenic activities, resulting in increasing greenhouse gases in the environment and leading to global warming and weather drifts. Extremophilic fungi, characterized by their exceptional properties to survive extreme habitats, harbor great potential in mitigating climate change effects. This review provides insight into the potential applications of extremophilic fungi in climate change mitigation strategies. They are able to metabolize organic biomass and degrade carbon compounds, thereby safely sequestering carbon and extenuating its release into the environment as noxious greenhouse gases. Furthermore, they possess extremozymes, which break down recalcitrant organic species, including lignocellulosic biomass and hydrocarbons. Enzymatic machinery equips these extremophilic fungi to perform the bioremediation of polluted environments. Extremophilic fungi can also be exploited for various biological interventions, such as biofuels, bioplastics, and other bioprocessing applications. However, these fungi characterize a valued but underexplored resource in the arsenal of climate change mitigation strategies.

Influence of biodestructors on sequestration of labile carbon compounds in the soil

Ukraine stands as a testament to agricultural wealth due to its fertile soils, most notably, its significant share of the world’s chornozem. Rich soil is fundemantal to agricultural production, and therefore the success of the agricultural industry heavily relies on the fertility of the soil. However, modern agricultural practices in Ukraine, have led to increased anthropogenic impact on soils, affecting their biodiversity and humus content. In this regard, it is becoming increasingly important to perform comprehensive studies of microbiological, biochemical and chemical processes in the soil in response to different agricultural interventions. The urgent need to restore natural ecosystems to preserve their biodiversity and ensure ecological stability poses new scientific challenges, emphasizing the importance of urgent measures aimed at protecting the environment from pollution and degradation. This research aims to explore the effects of biodestructors on the deposition of labile carbon compounds in the soil during long-term consistent corn cultivation. The research was conducted during 2020–2023 within the framework of a stationary field experiment of the scientific research department of the «Druzhba Nova» in Varva village, Chernihiv region. The soil is a typical low-humus chornozem with the experiment focusing on a monoculture corn crop rotation. The DKC 4351 corn hybrid was sown at a density of 82 thousand units per hectare, employing a three-part experiment design: 1) a UAN control at 32–28 l/ha, 2) Ecostern Classic at 2 l/ha combined with UAN 32–28 l/ha, and 3) Ecostern Bacterial at 2 l/ha alongside Ecostern Trichoderma at 1 l/ha and UAN 32–28 l/ha. In the present study, the influence of biodestructors on soil’s agrochemical and microbiological indicators, as well as corn yield was evaluated. In a long-term stationary field experiment conducted on a typical low-humus chornozem, we investigated the influence of microbial preparations — plant residue biodestructors — on the deposition of labile carbon compounds in the soil under continuos corn cultivation. The application of Ecostern Classic and a combination of Ecostern Bacterial + Ecostern Trichoderma biodestructors resulted in an increase of labile carbon content by 0.11% and 0.18%, respectively, compared to the control. The aim of further analysis was to determinate the dynamics of the organic matter transformation coefficient, which is a marker of enhanced microbiological activity in the soil and a predominance of organic matter synthesis over its mineralization. In treatments utilizing biodestructors, this indicator was significantly higher than control values throughout the study. The survival of the fungal bioagent from Ecostern Classic and Ecostern Trichoderma bioproducts in the soil was monitored by assessing the population dynamics of the Trichoderma genus species. Results demonstrated an increase by an average of 19 thousand CFU/g with Ecostern Classic and by 34 thousand CFU/g with the combined use of Ecostern Bacterial with Ecostern Trichoderma, compared to 28 thousand CFU/g in control soil samples. This may indirectly indicate a successful colonization of the bioagent in treated soils. Using BIOTREX technology to evaluate the soil’s ecophysiological diversity, we found that the diversity index increased from 3.66 in control samples to between 4.87 and 5.61 in treatments with biodestructors. According to the further BIOTREX assessment, the use of biodestructors not only increased soil biodiversity, but also improved soil health. The application of these biodestructors also significantly boosted corn grain yield with an increase of 0.32 t/ha with Ecostern Classic treatment and 0.18 t/ha with the combined use of Ecostern Bacterial with Ecostern Trichoderma, compared to control.

The potential of calcium oxide nanocatalyst from chicken eggshells for biodiesel production using chicken fat waste

This research aims to synthesize biodiesel using raw materials from chicken fat waste and a catalyst from eggshells (EGS). The eggshells used as a catalyst were calcined (EGS_calcined) and uncalcined (EGS_uncalcined). The calcination process was carried out at a temperature of 900 °C with a heating rate of 5 °C/minute under static air conditions for 24 h. The X-ray Diffraction diffractogram showed that the calcination process has successfully converted the calcium carbonate compound in the eggshell into calcium oxide. The particle sizes of EGS_uncalcined and EGS_calcined catalysts were 509.2 nm and 2.9 nm, respectively. Chicken fat transesterification reaction conditions were optimized to increase biodiesel yield, including variations in EGS catalyst mass (1–3 % of chicken fat extract (oil) weight), oil and methanol mole ratio (1:5–1:30), temperature (55–75 °C), and reaction time (30–180 min). The EGS catalyst mass conditions, oil and methanol mole ratio, temperature, and reaction time that produced the highest yield (93 %) were 1.5 % (w/w oil), 1:10, 65 °C, and 120 min, respectively. Research showed that the calcined EGS_catalyst performs better than the uncalcined EGS_catalyst.