Search Results (141)

The use of methane as a carbon source for producing bacterial single-cell protein (SCP) has been one of the most interesting developments in recent years. Most of these upcoming industries are using a methanotroph, Methylococcus capsulatus Bath, for SCP production using natural gas as the substrate. In the present study, we have explored the possibility of using an indigenously isolated methanotroph from a rice field in India, Methylomagnum ishizawai strain KRF4, for producing SCP from biogas [derived from cow dung]. The process was eco-friendly, required minimal instruments and chemicals, and was carried out under semi-sterile conditions in a tabletop fish tank. As the name suggests, Methylomagnum is a genus of large methanotrophs, and the strain KRF4 had elliptical to rectangular size and dimensions of ~4–5 µm × 1–2 µm. In static cultures, when biogas and air were supplied in the upper part of the growing tank, the culture grew as a thick pellicle/biofilm that could be easily scooped. The grown culture was mostly pure, from the microscopic observations where the large size of the cells, with rectangular-shaped cells and dark granules, could easily help identify any smaller contaminants. Additionally, the large cell size could be advantageous for separating biomass during downstream processing. The amino acid composition of the lyophilized biomass was analyzed using HPLC, and it was seen that the amino acid composition was comparable to commercial fish meal, soymeal, Pruteen, and the methanotroph-derived SCP-UniProtein^®. The only difference was that a slightly lower percentage of lysine, tryptophan, and methionine was observed in Methylomagnum-derived SCP. Methylomagnum ishizawai could be looked at as an alternative for SCP derived from methane or biogas due to the comparable SCP produced, on the qualitative level. Further intensive research is needed to develop a continuous, sustainable, and economical process to maximize biomass production and downstream processing. Full article

Biodegradation is a green and efficient method for lignin depolymerization and conversion. In order to screen potential bacterial strains for efficient lignin degradation, composts of cow dung and wheat straw were prepared, and the dynamic changes in the predicted bacterial community structure and function in different periods of the composts were investigated. Then, bacteria with an efficient lignin degradation ability were finally screened out from the compost samples. Based on the monitoring results of the physicochemical indexes of the composting process, it was found that the temperature and pH of the compost firstly increased and then decreased with the extension of time, and the water content and C/N gradually decreased. High-throughput sequencing of compost samples from the initial (DA), high-temperature (DB), and cooling (DC) periods revealed that the number of OTUs increased sharply then stabilized around 2000, and the alpha diversity of the bacterial community decreased firstly and then increased. The predominant phyla identified included Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidetes, determined by the relative abundance of beta-diversity-associated species. Functional gene analysis conducted using Tax4Fun revealed that the genes were primarily categorized into Metabolism, Genetic Information Processing, Environmental Information Processing, and Cellular Processes. Based on the decolorization of aniline blue and the degradation efficiency of alkali lignin, eight bacterial strains were isolated from compost samples at the three stages. Cupriavidus sp. F1 showed the highest degradation of alkali lignin with 66.01%. Cupriavidus sp. D8 showed the highest lignin degradation potential with all three enzyme activities significantly higher than the other strains. The results provide a strategy for the lignin degradation and utilization of biomass resources. Full article

Anaerobic fermentation has been recognized as an effective approach to harness livestock manure resources. In the present study, cow dung and pig manure were employed as fermentation substrates. These were subjected to co-fermentation experiments with sodium hydroxide-pretreated corn straw. Additionally, biochar derived from artificial wetland substrate was introduced as a conditioner to investigate the impact of varying addition quantities on the pretreated anaerobic co-fermentation process. Our findings indicate that for the anaerobic co-fermentation of cow dung, an optimal addition of 4% biochar reduced the gas production cycle by 35–45%, although the total methane yield remained relatively unchanged. Conversely, in the anaerobic co-fermentation of pig manure, a 6% biochar addition proved most effective. This adjustment, while not significantly altering the gas production cycle, led to a marked increase in the total methane content, ranging from 18.53% to 150.18%. The PCA analysis results of the cow manure experimental group showed a significant positive correlation between the addition of biochar and ammonia nitrogen. For the pig manure fermentation system, the addition of biochar can increase the final methane production potential, from 47.43 mL/g VS to 122.24 mL/g VS in the P2C experimental group. Biochar mainly regulates the activity of anaerobic bacteria through changes in pH and conductivity, thereby affecting methane production. Full article

The addition of alkaline amendments is considered an important strategy to alleviate soil acidification, with profound impacts on soil nitrogen (N) transformations such as nitrification as well as greenhouse gas (GHG) nitrous oxide (N₂O) emissions. Nitrification inhibitors (NIs) have been widely recognized to effectively mitigate N₂O emissions by depressing the nitrification process. However, the effectiveness of NIs on N₂O emissions reduction under different alkaline amendments remains largely unknown, hindering our knowledge of the optimal soil acidification mitigation strategies. In this study, the effects of NIs in combination with different alkaline amendments on N₂O emissions were assessed on typical acid soils collected from four sites during a 28-day aerobic incubation experiment. Treatments included four alkaline amendments (quicklime, chicken manure, cow dung, biochar) and no amendment control, designated as CaO, CM, CD, BC, and CK, combined with a typical NI (3,4 dimethylpyrazole phosphate, DMPP) applied at 2 mg soil kg⁻¹ or non-NI applied, respectively. Both individual amendments and their combination with DMPP significantly elevated the soil pH by 4.9–64.2% compared with the CK treatment, with the effectiveness ranking as CaO > CM ≈ CD > BC. Cumulative N₂O emissions were stimulated by the individual application of CaO, CM, and CD but were reduced by BC application compared with the CK treatment. Changes in N₂O emissions were positively correlated with the responses of the net N mineralization and nitrification rates to individual amendments, which were regulated by changes in the soil pH. The suppressive effects of NI combined with individual amendments on N₂O emissions were significant in the CaO treatment with a reduction ranging from 3.3% to 60.2%, which was attributed to decreased abundances of ammonia-oxidizing bacteria (AOB). Therefore, we concluded that the combined application of CaO and DMPP could be considered as a suitable mitigation strategy for addressing soil acidification through optimized N management. Additionally, BC can serve as a supplementary practice to simultaneously improve soil fertility. These insights are crucial for developing integrated fertilization management strategies to mitigate soil acidification with low N loss risks. Full article

Labile organic carbon (OC), a dynamic component of soil organic carbon (SOC), is essential for improving soil health, fertility, and crop productivity, particularly when organic and inorganic amendments are combined. However, limited research exists on the best amendment strategies for restoring degraded gleyic solonetz soggy sodic (GSSS) soils in West Africa’s coastal zones. A three-year field study (2017–2019) assessed the effects of various combinations of organic (mature or composted cow dung, with or without biochar) and inorganic inputs on soil organic carbon fractions, total carbon stocks, and the Carbon Management Index (CMI) in GSSS soils of Sege, Ada West District, Ghana. The results showed that organic and inorganic combinations outperformed the sole inorganic NPK treatment and the control, particularly in the topsoil. Composted cow dung with mineral fertilizer (CCfert) was especially effective, significantly increasing labile OC, SOC stock, and CMI by 35.3%, 140.5%, and 26% in the topsoil compared to the control and by 28%, 77.8%, and 4.3% compared to NPK alone. In the subsoil, mature cow dung-based treatments performed better. These findings highlight the potential of integrated organic and inorganic strategies, especially those based on composted manure, to rehabilitate degraded sodic soils, build carbon stocks, and improve soil quality for sustainable agriculture in coastal West Africa. Full article

Calocybe indica (milky mushroom), an edible mushroom with significant nutritional value, shows potential for cultivation in subtropical regions. Investigating the composition and diversity of the microbial community structure of the casing materials of C. indica is of great significance for understanding the stable yield of the mushroom. This study evaluated four casing materials—loamy soil (LS), loamy soil + cow dung (LS + CD), loamy soil + sand (LS + S), and plant ash (PA)—for their effects on mushroom yield, soil physicochemical properties, and microbial dynamics. The results demonstrated that LS + CD significantly enhanced the yield (2078.50 g) and fruiting body quality, with the shortest pinhead formation time (7.67 days) and superior morphological traits (e.g., cap diameter: 10.10 cm). Physicochemical analysis revealed LS + CD’s elevated moisture retention (19.7%), nutrient availability (e.g., available P: 59.63 mg/kg), and microbial biomass (C: 399.22 mg/kg), alongside a distinct microbial community dominated by Basidiomycota and Actinobacteria. Conversely, LS + S exhibited poor performance due to low water retention and nutrient deficiencies. Redundancy analysis highlighted strong correlations between soil nutrients (nitrogen, potassium, phosphorus) and microbial composition, with LS + CD fostering a microbiome conducive to mushroom growth. These findings underscore LS + CD as the optimal casing material for C. indica cultivation, improving both yield and soil health. Future studies should explore the functional roles of key microbes and refine organic amendments for sustainable practices. Full article

Biol is a liquid product, obtained by anaerobic fermentation of local inputs, which improves the health of agroecosystems, which is an emerging area in agronomy. The aim of this study consists of the preparation of two biols from inoculums of cow dung (BCD) and native forest duff (BNF) by using specific biodigesters and commercial inputs. The biol characterization was made in terms of mineral (ionic and complex forms), amino acids, hormones and volatile compounds, along with Pfeiffer circular chromatography during fermentation monitoring. The results showed a pH acidic in both biols (4.5–5.5), which is higher for BCD. Also, this biol had higher content in several macro- and micronutrients in ionic (nitrates, phosphates, calcium, iron and sodium) and complex forms (calcium, iron and potassium). Both have interesting content in amino acids and hormones. The absence of microorganisms in the final products could be due to the presence of volatile compounds such as pyrazines and sulfoxides. Along with this, other volatile compounds such as esters were identified, which can be responsible for their pleasant odor. The novelty of this work is to provide a protocol for obtaining biols and to demonstrate their potential to be used as biofertilizers. Full article

Climate change and overgrazing significantly constrain the sustainability of meadow land and vegetation in the livestock industry on the Tibetan–Plateau ecosystem. In context of climate change mitigation, grassland soil C sequestration and forage sustainability, it is important to understand how manure regimes influence SOC stability, grassland soil, forage structure and nutritional quality. However, the responses of SOC fractions, soil and forage structure and quality to the influence of manure gradient practices remain unclear, particularly at Tianzhu belt, and require further investigation. A field study was undertaken to evaluate the soil bulk density, aggregate fractions and dynamics in SOC concentration, permanganate oxidizable SOC fractions, SOC stabilization and soil nutrients at the soil aggregate level under manure gradient practices. Moreover, the forage biodiversity, aboveground biomass and nutritional quality of alpine meadow plant communities were also explored. Four treatments, i.e., control (CK), sole sheep manure (SM), cow dung alone (CD) and a mixture of sheep manure and cow dung (SMCD) under five input rates, i.e., 0.54, 1.08, 1.62, 2.16 and 2.70 kg m⁻², were employed under randomized complete block design with four replications. Our analysis confirmed the maximum soil bulk density (BD) (0.80 ± 0.05 g cm⁻³) and micro-aggregate fraction (45.27 ± 0.77%) under CK, whilst the maximum macro-aggregate fraction (40.12 ± 0.54%) was documented under 2.70 kg m⁻² of SMCD. The SOC, very-labile C fraction (Cfrac₁), labile C fraction (Cfrac₂) and non-labile/recalcitrant C fraction (Cfrac₄) increased with manure input levels, being the highest in 2.16 kg m⁻² and 2.70 kg m⁻² applications of sole SM and the integration of 50% SM and 50% CD (SMCD), whereas the less-labile fraction (Cfrac₃) was highest under CK across aggregate fractions. However, manures under varying gradients improved SOC pools and stabilization for both macro- and micro-aggregates. A negative response of the carbon management index (CMI) in macro-aggregates was observed, whilst CMI in the micro-aggregate fraction depicted a positive response to manure addition with input rates, being the maximum under sole SM addition averaged across gradients. Higher SOC pools and CMI under the SM, CD and SMCD might be owing to the higher level of soil organic matter inputs under higher doses of manures. Moreover, the highest accumulation of soil nutrients,, for instance, TN, AN, TP, AP, TK, AK, DTPA extractable Zn, Cu, Fe and Mn, was recorded in SM, CD and SMCD under varying gradients over CK at both aggregate fractions. More nutrient accumulation was found in macro-aggregates over micro-aggregates, which might be credited to the physical protection of macro-aggregates. Overall, manure addition under varying input rates improved the plant community structure and enhanced meadow yield, plant community diversity and nutritional quality more than CK. Therefore, alpine meadows should be managed sustainably via the adoption of sole SM practice under a 2.16 kg m⁻² input rate for the ecological utilization of the meadow ecosystem. The results of this study deliver an innovative perspective in understanding the response of alpine meadows’ SOC pools, SOC stabilization and nutrients at the aggregate level, as well as vegetation structure, productivity and forage nutritional quality to manure input rate practices. Moreover, this research offers valuable information for ensuring climate change mitigation and the clean production of alpine meadows in the Qinghai–Tibetan Plateau area of China. Full article

The current work investigates the intensification process of the biological oxidation (BO) of a pharmaceutical effluent using ultrasound (US)-based pretreatment methods. US, in combination with chemical oxidants, like hydrogen peroxide (H₂O₂), Fenton, potassium persulphate (KPS), and peroxone, was used as a pretreatment technique to enhance the efficacy of BO, as BO alone could only bring about 16.67% COD reduction. The application of US under the optimized conditions of a 70% duty cycle, 120W of power, pH 2, and at a 30 °C temperature resulted in 12.3% COD reduction after 60 min, whereas its combination with oxidants at optimized loadings resulted in a higher COD reduction of 20% for H₂O₂ (2000 ppm), 23.08% for Fenton (1:1 Fe:H₂O₂), and 30.77% for the US + peroxone approach (400 mg/h of ozone with 2000 ppm H₂O₂). The pretreated samples did not produce any toxic by-products, as confirmed by a toxicity analysis using the agar well diffusion method. A cow-dung-based sludge was acclimatised specifically for use in BO. The treatment time for BO was set to 8 h, and the US + peroxone-pretreated samples showed a maximum overall COD reduction of 60%, which is about three times that observed with only BO. This work clearly demonstrates the enhancement of the biodegradation of a complex recalcitrant pharmaceutical effluent using a US-based pretreatment. Full article

The dichotomy of striking a balance between sustainable food crop production for the skyrocketing human population and ensuring agricultural practices that mitigate environmental degradation has prompted much research into sustainable crop production methods. The application of amendments has become an integral part of arable soil management in restoring declining soil fertility for sustainable and high-quality crop production. This study was conducted on lettuce and carrot cultivated on soil treated with three different amendments: cow dung, sewage sludge, and nitrogen–phosphorus–potassium (NPK) mineral fertilizer. The vegetables were harvested at maturity at 60 and 110 days for lettuce and carrot, respectively, dried in a hot air oven, crushed, and then digested to obtain an aliquot sample. The level of macronutrients was quantified from the aliquots using inductively coupled plasma optical emission spectrometry (ICP-OES), Avio 550 Max, PerkinElmer, USA. It was observed that both soil treatment and types of vegetables significantly impacted the level of mineral contents in the vegetables. The highest values of 58.00 ± 8.36 mg/kg and 72.97 ± 12.53 mg/kg were recorded for Na and P in carrots from soil treated with sewage sludge, respectively. The highest values of 247.97 ± 17.07 mg/kg and 104.72 ± 4.12 mg/kg were recorded for Ca and Mg in lettuce from sewage sludge-treated soil, respectively. Similarly, the highest value of 546.75 ± 76.44 mg/kg for K was also recorded in lettuce, but from cow dung-treated soil. The overall pattern of mineral accumulation by vegetables shows that carrots accumulate more Na than lettuce, and lettuce accumulates more Mg, Ca, and K than carrots, while there was no significant difference in the level of P in both lettuce and carrots. The findings reveal that lettuce and carrots from soil treated with organic manure cow dung and sewage sludge accumulated higher mineral contents of most of the investigated minerals. It was also observed that lettuce accumulated higher contents of most of the minerals investigated. This study therefore concludes that organic manures are better alternatives to mineral fertilizers for vegetable production, which supports the effort to strike a balance between sustainable and ecofriendly agriculture. Full article

Efficient biogas production significantly impacts greenhouse gas (GHG) emissions and carbon sequestration by reducing emissions and enhancing carbon storage. Nonetheless, the consistency and optimization of biogas production are hindered by fluctuations in key input variables, namely, pH, moisture content, organic loading rate (OLR), and temperature, which significantly impact the quality of agricultural waste biomass and biogas production. Any fluctuations in these variables can affect biogas productivity. This study aims to provide valuable optimization parameters for maximum biogas production using rice straw and cow dung as agricultural waste biomass for biogas input materials. Therefore, machine learning techniques such as multilayer perceptron feedforward neural networks with a particle swarm optimization (PSO) combination generate optimal values for each variable for maximum biogas production. This study uses three variants of the training function for neural networks, namely gradient descent with momentum and adaptive learning rate, gradient descent with momentum, and gradient descent with adaptive learning rate. The findings reveal that, under an optimum pH value of 6.0000, a humidity of 62.3176%, an OLR of 67.6823 kg.m³/day, and a temperature of 37.0482 °C, biogas production has the potential to increase to 2.91 m³/day with a high accuracy testing value of R² = 0.90. These methods in use accurately predict the optimal parameters, with a maximum deviation of 8.48% from experimentally derived values and mean square error (MSE) of 0.0051243. This study emphasizes the benefits of using multilayer perceptron feedforward neural networks and particle swarm optimization to optimize operational parameters and accurately predict biogas production. Full article

As a type of high-water-content agricultural waste, vegetable waste (VW) is extremely prone to spoilage and environmental pollution. Anaerobic digestion (AD) technology can accelerate the degradation of VW; however, its direct reaction might encounter the risk of termination due to excessive acidification. How to effectively prevent excessive acidification and further accelerate the degradation and maturity of VW remains a significant challenge at present. This paper employed the methods of AD of biogas and aerobic treatment (AT) of biogas slurry (BS) to develop a set of three groups of coupled devices for thermostatic anaerobic and aerobic processes with temperature control by solar collectors. The reaction process was further facilitated by adopting a mixture of raw materials and exogenous additives. In Lanzhou, a comparative experiment was carried out to examine the impacts of a blank group (BG) (additive-free), a 1 g/L urea group (UG), and a 1 g/L plant ash group (PG) on the decomposition process of the mixture of cow dung and tomato stems and leaves. The thermostatic batch wet AD stage of the mixed raw materials at (26 ± 2 °C) lasted for 49 days. The substrate after digestion underwent aerobic aeration treatment for 8 h at different temperatures and different aeration rates. The results show that the system could be initiated smoothly and maintain stable operation in winter under the temperature control of the solar collector; adding additives during AD significantly boosted biogas and methane production during the first 28 days, with urea being the most effective. During the subsequent aerobic phase, UG demonstrated the highest bio-effectiveness under optimized conditions of (30 ± 1 °C) and an aeration rate of 12 L/min. Comprehensive analysis revealed that the optimal operation strategy was identified as the use of UG with a 29-day reaction cycle. The research results have significant referential value for the rapid decomposition of high-water-content agricultural and livestock waste in cold regions. Full article

Background/Objectives: The increasing threat of antimicrobial resistance (AMR) to global public health urgently needs attention. Misuse of antimicrobials in sectors such as dairy farming has led to the emergence and spread of resistant bacteria and genes. This study investigated AMR patterns and profiles of Escherichia coli (E. coli) from various sources, including soil, effluent, cow dung, and milk. Methods: A total of 192 samples were collected, comprising environmental samples (soil and effluent), cow dung samples, and milk samples from eight dairy farms in Selangor, Malaysia. The spread plate method was employed to isolate E. coli, and all the isolates were subjected to Gram staining to identify Gram-negative, rod-shaped bacteria. The Vitek^® 2 system was used for E. coli identification and susceptibility testing. Results: The prevalence of E. coli identified in the eight farms was 66.1%. A total of 360 E. coli isolates were successfully isolated, and 19.7% of the isolates presented AMR with ampicillin exhibiting the highest resistance (18.3%), followed by trimethoprim–sulfamethoxazole (8.9%). Additionally, 8.9% of them were multidrug resistant, which could be divided into 16 patterns. For the extended spectrum beta-lactamase screening, nine isolates were positive. Conclusions: This finding emphasizes the rise in resistant isolates in the growing dairy industry and underscores the urgency of addressing the potential reservoir of AMR. Therefore, essential measures such as continuous surveillance and effective antimicrobial stewardship programs are crucial for regulating veterinary antimicrobial use. Research on the mechanisms driving the development and dissemination of AMR is imperative for addressing One Health concerns. Full article

Context: Biochar can affect the storage and forms of nitrogen; thus, it may also play a role in altering the nitrogen cycle during the fermentation process of cow dung into organic fertilizer. Objective: To elucidate the mechanism and process of nitrogen transformation during the composting of cow manure with biochar, a comparative experiment was conducted. Method: This study investigates the use of biochar as a medium to enhance nitrogen storage during the aerobic composting of cow manure. The effectiveness was verified through a rapid composting experiment. Result and Conclusions: The results demonstrated that adding 5% biochar to the compost pile increased the total nitrogen content in manure by 12%. Specifically, the pyrrolic nitrogen in the composted cow manure increased from 38% to 44%, and the carbon-nitrogen ratio improved from 35% to 37%. Analysis of surface functional groups indicated that the C=O and C=C bonds in biochar played a key role in modifying nitrogen storage. Microbial analysis showed that biochar could significantly enhance the regional competitiveness of microorganisms, such as Cellvibrio, thereby boosting the expression of functional genes involved in the nitrification process, including amoABC, hao, and nxrAB. Therefore, adding 5% biochar not only enhances nitrogen storage in organic fertilizer but also changes the microbial population structure. Significance: This study carries substantial implications for the application of Biochar in the field, as well as for the development of microbial fertilizers based on cow manure. Full article

In light of the issue concerning excessive fertilization that prevails in the Huang-Huai-Hai Plain, through conducting a 13-year long-term positioning experiment, the sustainability of a wheat and maize double-cropping soil system under different fertilization strategies is evaluated using the triangular area method. The objective is to establish a theoretical basis for the development and implementation of appropriate fertilization practices in the Huang-Huai-Hai Plain. In the protracted long-term experiment, chemical fertilizer (F) was taken as the control (CK) and three distinct treatments combining organic and inorganic fertilizers were used: chemical fertilizer with straw mulching (FS), chemical fertilizer with cow dung (FM), and chemical fertilizer with cow dung and straw mulching (FMS). Between 2018 and 2019, a non-fertilization treatment was concurrently incorporated in parallel on the foundation of each existing fertilization treatment. The results indicated that following prolonged fertilization, the soil nutrient content, enzyme activity, and crop yield of each organic fertilizer treatment were significantly greater than those of the chemical fertilizer treatment alone, resulting in a more stable yield. After two years of discontinuation of fertilizer cultivation, the soil fertility indexes of each treatment exhibited a notable decline. However, the rate of decrease in soil fertility indexes for the three organic fertilizer treatments was lower compared to that of the single application of chemical fertilizer treatment, suggesting that long-term allocation of organic + inorganic fertilizers contributes to better preservation of soil fertility. Through an assessment of the soil system’s sustainability under various treatments, it becomes evident that following a two-year cessation of fertilization, the sustainability indexes of the soils subjected to three long-term organic + inorganic fertilizer treatments (1.26, 1.29, and 1.27) exceeded that of the soil treated solely with chemical fertilizer (1.00). These findings provide further evidence supporting the notion that the combined application of organic and inorganic fertilizers can enhance the soil system’s capacity for sustainable production in wheat–maize farmland within the Huang-Huai-Hai Plain. Full article