Livestock Manure Research Articles

Effects of inocula on methane production and the microbial community in a rice straw anaerobic digestion system

Field experiments have shown that the mixed anaerobic digestion of straw with livestock and poultry manure can improve the efficiency of biogas production. We hypothesize that inoculation with livestock and poultry manure increase the efficiency of methane production by improving the diversity and structure of microbial community in the field anaerobic digestion system. In this study, an experimental system was established to simulate the microbial community of the mixed anaerobic digestion system in the field. The methane production and taxonomic composition of bacterial and archaeal communities in the rice straw anaerobic digestion systems were determined. We aim to reveal the effects of the inocula on the diversity and composition of bacterial and archaeal communities and the mechanism underlying the impact on biogas production in the field. The following results were obtained. (1) Inoculation significantly improved the efficiency of methane production in anaerobic digestion, and the best performance was achieved with treatment A (cleared biogas slurry), which obtained methane production that were 39.59 %, 106.85 %, and 123.00 % higher than in treatment B (pig manure extract), C (cleared biogas slurry + pig manure extract), and the control, respectively. (2) The inocula increased the abundance and diversity of bacterial communities in the early and middle stages and archaeal communities in the early stage. (3) The inocula also had a significant impact on bacterial and archaeal community composition in the early and middle stages. The inocula increased the relative abundance of Aquamicrobium_A, Proteiniphilum, and Cryptobacteroides but reduced the relative abundance of Macellibacteroides, Acinetobacter, and Phocaeicola. The dominant genus of archaeal community was altered from Methanosarcina to Methanocorpusculum. (4) It is concluded that inoculation significantly increase methane production as the inocula improve the abundance and diversity of bacteria and archaea of anaerobic digestion systems in the early and middle stages of digestion, as well as improve the structure and metabolic pathway of archaeal communities.

Cattle manure hydrochar posed a higher efficiency in elevating tomato productivity and decreasing greenhouse gas emissions than plant straw hydrochar in a coastal soil

Rehabilitation of degraded soil health using high-performance and sustainable measures are urgently required for restoring soil primary productivity and mitigating greenhouse gas (GHG) emission of coastal ecosystems. However, the effect of livestock manure derived hydrochar on GHG emission and plant productivity in the coastal salt-affected soils, one of blue carbon (C) ecosystems, was poorly understood. Therefore, a cattle manure hydrochar (CHC) produced at 220 °C was prepared to explore its effects and mechanisms on CH4 and N2O emissions and tomato growth and fruit quality in a coastal soil in comparison with corresponding hydrochars derived from plant straws, i.e., sesbania straw hydrochars (SHC) and reed straw hydrochars (RHC) using a 63-day soil column experiment. The results showed that CHC posed a greater efficiency in reducing the global warming potential (GWP, 54.6 % (36.7 g/m2) vs. 45.5–45.6 % (22.2–30.6 g/m2)) than those of RHC and SHC. For the plant growth, three hydrochars at 3 % (w/w) significantly increased dry biomass of tomato shoot and fruit by 12.4–49.5 % and 48.6–165 %, respectively. Moreover, CHC showed the highest promotion effect on shoot and fruit dry biomass of tomato, followed by SHC ≈ RHC. Application of SHC, CHC and RHC significantly elevated the tomato sweetness compared with CK, with the order of CHC (54.4 %) > RHC (35.6 %) > SHC (22.1 %). Structural equation models revealed that CHC-depressed denitrification and methanogen mainly contributed to decreased GHG emissions. Increased soil phosphorus availability due to labile phosphorus supply from CHC dominantly accounted for elevated tomato growth and fruit production. Comparably, SHC-altered soil properties (e.g., decreased pH and increased total carbon content) determined variations of GHG emission and tomato growth. The findings provide the high-performance strategies to enhance soil primary productivity and mitigate GHG emissions in the blue C ecosystems.

Life Cycle Assessment of Three Manure Treatment Modes in Large-scale Pig Farm

With the rapid development of China's livestock breeding industry, it is very important to efficiently deal with the pollution caused by livestock and poultry manure. In this study, the life cycle resource consumption and pollutant emission inventory of a large-scale pig farm were analyzed by life cycle assessment (LCA). The environmental impact potentials of three different modes of livestock and poultry manure treatment were analyzed, including aerobic composting, anaerobic fermentation and black soldier fly larvae (BSFL) treatment. Results showed that the environmental loads of BSFL treatment and anaerobic fermentation were much smaller than those of aerobic composting in the life cycle process of pig manure treatment. The environmental impacts of aerobic composting process were in the order of environmental acidification, eutrophication, and global warming; while the environmental impacts of anaerobic fermentation treatment and BSFL treatment process were in the order of global warming, environmental acidification, and eutrophication. It is recommended to strengthen the emission of CO2 and NH3 in the pig manure treatment process to reduce their environmental impacts.

Influence of the Antibiotic Oxytetracycline on the Morphometric Characteristics and Endophytic Bacterial Community of Lettuce (Lactuca sativa L.).

Antibiotics enter the soil with compost prepared from livestock manures and other sources. There is concern that they may influence plant growth and cause antibiotic resistance in soil and plant endospheric microbiomes. In the present work, lettuce plants were cultivated in soil and hydroponics spiked with oxytetracycline (0, 15, and 300 mg × kg-1 and 0, 15, and 50 mg × L-1, respectively) during a 28-day greenhouse experiment. It was revealed that the antibiotic reduced the chlorophyll content, the biomass, and the length of the roots and stems by 1.4-4.7, 1.8-39, 2.5-3.2, and 1.8-6.3 times in soil and in hydroponics. The copy numbers of the tet(A) and tet(X) genes were revealed to be 4.51 × 103-1.58 × 105 and 8.36 × 106-1.07 × 108 copies × g-1, respectively, suggesting the potential migration of these genes from soil/hydroponics to plant roots and leaves. According to a non-metric multidimensional scaling (NMDS) analysis of the 16S rRNA amplicon sequencing data, endospheric bacterial communities were similar in leaves and roots independent of the growing substrate and antibiotic concentration. While soil bacterial communities were unaffected by the presence of antibiotics, hydroponic communities exhibited dependency, likely attributable to the absence of the mitigating effect of soil particle absorption.

Comparison of Solubilization Treatment Technologies for Phosphorus Release from Anaerobic Digestate of Livestock Manure

This study addresses the imminent threat of phosphorus (P) depletion, investigating anaerobically digested livestock manure as a high-concentration P alternative. To achieve this objective, Visual MINTEQ software, a general-purpose software used for chemical equilibrium modeling, was employed to simulate the alteration in P species fractions at different pH levels. The investigation further examined the variation in P release rates and electrical energy consumption across various pretreatment processes as influenced by pH levels. The results indicate a significant pH influence on P release, with enhanced efficacy under both acidic and alkaline conditions. At pH 2, total P concentration peaked at 684 mg·L−1, with 83.0% reactive P, in contrast with pH 10 conditions, which exhibited 504 mg·L−1 and 48.4%, respectively. P release increased with reaction time across all pretreatment processes. Sonication notably increased P release by 126.9%, with the highest reactive P release efficiency at 2.09 mg·L−1·Wh−1, emerging as an optimal process. Simulation results using Visual MINTEQ software indicate that the inclination for P release in alkaline conditions can be ascribed to the heightened presence of hydroxyapatite, brushite, and Ca-Fe (III)-phosphate bonds with rising pH levels. These simulation results, which are consistent with the experimental results, affirm the crucial influence of cations in determining P release on pH values.

Accumulation of livestock manure–derived heavy metals in the Hexi Corridor oasis agricultural alkaline soil and bioavailability to Chinese cabbage (Brassica pekinensis L.) after 4-year continuous application

Hexi Corridor is one of the most important base of vegetable producing areas in China. Livestock manure (LM) applied to agricultural field could lead to soil heavy metal (HM) pollution. Previous studies have focused on HM pollution following LM application in acidic polluted soils; however, fewer studies have been conducted in alkaline unpolluted soils. A 4–year field vegetable production experiment was conducted using pig manure (PM) and chicken manure (CM) at five application rates (0, 15, 30, 45, and 60 t ha−1) to elucidate potential risks of HMs in an alkaline unpolluted soil in the Hexi Corridor oasis agricultural area and HM uptake by Chinese cabbage. The results showed that LM application caused a significant build–up of Cu, Zn, Pb, Cd, and Ni content in topsoil by 30.6–99.7%, 11.4–51.7%, 1.4–31.3%, 5.6–44.9%, 14%–40.8%, respectively. The Cd, Cu, Zn could potentially exceed the soil threshold in next 8–65 years after 15–60 t ha−1 LM application. Under LM treatment, the soil DTPA–extractable Cu, Zn, Fe, the acid–extractable fraction of Cu, Zn, Fe, Cd, Ni, and the Oxidable fraction of Cu, Zn, Fe, Mn, Cd, Ni significantly increased, but the DTPA–extractable Pb, Cd, the acid–extractable fraction of Pb, and the reducible fraction of Cd significantly decreased. Cu and Zn could migrate to the deeper soil and relatively increase in DTPA–extracted Cu, Zn were found in 20–40 cm soil depth after LM application. The pH and SOM could influence the bioavailability of HMs in soil. The bioaccumulation factor and transfer factor (TF) values were <1 except Mn (TF > 1). HMs in leaf did not approach the threshold for HM toxicity due to the “dilution effect”. Recommend the type of manure was the PM and the annual PM application rate was 30 t ha−1 to ensure a 20–year period of clean production in alkaline unpolluted Fluvo–aqiuc vegetable soils.

The dynamic characteristics of multi‐media carbon pollution and their spatial influencing factors: A case study of the Greater Bay Area of China

AbstractFor urban agglomerations that contain multiple interconnected cities, carbon pollution mitigation is particularly challenging due to the complex pollution transfer among environmental media and among cities. Insufficient attention has been paid to the city‐level metabolic processes of carbon in diverse physicochemical forms and their spatial interactions, impeding the identification and management of multi‐media carbon pollution from the integrated perspective of the whole urban agglomeration. Using the Greater Bay Area of China as a case, this study reveals the dynamic characteristics and spatial influencing factors of multi‐media carbon pollution covering 30 consecutive years based on substance flow analysis and a spatial econometric model. We find increasing necessity for controlling carbon pollution in the solid state, which reached 1890 Gg C/a in 2018 and was significantly higher than that in the gaseous (290 Gg C/a) and liquid (730 Gg C/a) state. Cross‐media transfer of carbon pollution made an increasingly substantial contribution to total carbon pollution from 14.6% to 20.7%, stressing the need for treatment and harmless disposal of sludge and the control of CH4 produced from waste landfilling, wastewater treatment, and livestock manure. Relocation of heavily polluting industries and variances at the level of environmental regulation between cities causes spatial transfer of carbon pollution, while the improvement of industrial structure and the advancement of pollution treatment technology have a positive demonstration effect for carbon pollution abatement of the neighboring cities. This study demonstrates the necessity of multi‐media and multi‐city integrities in carbon pollution mitigation within clustered cities.

Effects of chicken manure‐modified biochar on the adsorption capacity of tetracycline and abundance of antibiotic resistance genes in soil

AbstractLarge quantities of livestock manure not only occupy farmland but also serve as the primary source of antibiotics and antibiotic resistance genes (ARGs) in agricultural soil. To enhance the resource utilization of animal manure and mitigate ecological risks associated with antibiotics in agroecosystems, chicken manure was used as a raw material for biochar production. The manure derived biochar (MB) was modified with an alkali–acid two‐step modification process. The results showed that the total pore volume and surface area of alkali–acid modified MB (AMMB) was significantly increased about three and five times, respectively after modification. The SEM images showed that the surface of AMMB had a more regular and clearer structure with fewer impurities. The improvement of surface properties of AMMB significantly increased its adsorbing capacity of tetracycline in the soil. The adsorption kinetics of tetracycline by AMMB were better fitted by the pseudo‐second‐order kinetic model, suggesting that the adsorption of tetracycline on biochar followed the process of chemisorption. The adsorption mechanisms mainly involved the pore filling, hydrophobic effect, and π–π EDA interaction. Moreover, after a 60 days amendment of AMMB, the total relative abundances (RAs) of tested tetracycline resistance genes (TRGs) in soil decreased significantly, which suggested that AMMB can be a potential material to reduce risks of antibiotics and its resistance genes.

Assessing Ammonia and Greenhouse Gas Emissions from Livestock Manure Storage: Comparison of Measurements with Dynamic and Static Chambers

Emission quantification from the agricultural sector, and especially from livestock manure management, is relevant for assessing mitigation strategies and for inventory purposes. There are different direct techniques used to monitor emissions from quiescent surfaces. Common techniques include the closed static chamber and the open dynamic chamber. The aim of this study was to evaluate and compare different direct methods, two dynamic hoods and one static hood, for monitoring NH3 and greenhouse gas (GHG) emissions (N2O, CO2, and CH4) from different emission sources. These sources are ammonia solutions and different by-products of manure (compost, liquid fraction of digestate, and solid fraction of pig slurry). The use of dynamic hoods, despite their differences in size, operation, and applied air flux, presents comparable emission rates for all emissions and compounds assayed. These rates are always higher than those obtained using static hoods. Therefore, it can be concluded that the use of dynamic hoods is a valuable technique for refining the indirect estimation of emissions.

Soil-specific responses in the antibiotic resistome of culturable Acinetobacter spp. and other non-fermentative Gram-negative bacteria following experimental manure application.

Acinetobacter spp. and other non-fermenting Gram-negative bacteria (NFGNB) represent an important group of opportunistic pathogens due to their propensity for multiple, intrinsic, or acquired antimicrobial resistance (AMR). Antimicrobial resistant bacteria and their genes can spread to the environment through livestock manure. This study investigated the effects of fresh manure from dairy cows under antibiotic prophylaxis on the antibiotic resistome and AMR hosts in microcosms using pasture soil. We specifically focused on culturable Acinetobacter spp. and other NFGNB using CHROMagar Acinetobacter. We conducted two 28-days incubation experiments to simulate natural deposition of fresh manure on pasture soil and evaluated the effects on antibiotic resistance genes (ARGs) and bacterial hosts through shotgun metagenomics. We found that manure application altered the abundance and composition of ARGs and their bacterial hosts, and that the effects depended on the soil source. Manure enriched the antibiotic resistome of bacteria only in the soil where native bacteria had a low abundance of ARGs. Our study highlights the role of native soil bacteria in modulating the consequences of manure deposition on soil and confirms the potential of culturable Acinetobacter spp. and other NFGNB to accumulate AMR in pasture soil receiving fresh manure.

Estimation of Manure Emissions Issued from Different Chinese Livestock Species: Potential of Future Production

In this study, mathematical models are used to estimate the emissions of livestock excreta (LE) generated by China’s livestock industry more accurately. Also, the spatial relationship between provinces is analyzed. LE emissions are predicted for the next decade through appropriate parameters and non-parametric models. Additionally, a literature review is conducted to propose two hypotheses. As revealed by the research, there are four stages that LE emissions experience over time. From 2017 to 2021, LE emissions showed a trend of steady increase, suggesting a stronger awareness of the issue and the enforcement of more measures related to management and emission reduction. According to the results of a spatial analysis, there was no significant positive or negative correlation present between LE emissions in different provinces of China. In the selection of the prediction model, the BP-RE model achieved the best predictive performance. According to the prediction results, the fresh weight emissions from China’s livestock industry will increase by 24.53% by 2031, while dry weight emissions will decrease by 28.06%. Large-scale aquaculture farms show an upward trend, with fresh weight and dry weight emissions rising by 11.16% and 2.05%, respectively. Therefore, in light of this study’s findings, it is crucial for China to pursue additional measures in reducing LE emissions, despite the implementation of existing management policies. These insights can inform the development of livestock and poultry manure management policies and resource utilization strategies for the coming decade.

Mitigating Greenhouse Gas Emissions from Crop Production and Management Practices, and Livestock: A Review

Agriculture is the second most important greenhouse gas (GHG: methane (CH4) and nitrous oxide (N2O) emissions)-emitting sector after the energy sector. Agriculture is also recognized as the source and sink of GHGs. The share of agriculture to the global GHG emission records has been widely investigated, but the impact on our food production systems has been overlooked for decades until the recent climate crisis. Livestock production and feed, nitrogen-rich fertilizers and livestock manure application, crop residue burning, as well as water management in flood-prone cultivation areas are components of agriculture that produce and emit most GHGs. Although agriculture produces 72–89% less GHGs than other sectors, it is believed that reducing GHG emissions in agriculture would considerably lower its share of the global GHG emission records, which may lead to enormous benefits for the environment and food production systems. However, several diverging and controversial views questioning the actual role of plants in the current global GHG budget continue to nourish the debate globally. We must acknowledge that considering the beneficial roles of major GHGs to plants at a certain level of accumulation, implementing GHG mitigation measures from agriculture is indeed a complex task. This work provides a comprehensive review of agriculture-related GHG production and emission mechanisms, as well as GHG mitigation measures regarded as potential solutions available in the literature. This review also discusses in depth the significance and the dynamics of mitigation measures regarded as game changers with a high potential to enhance, in a sustainable manner, the resilience of agricultural systems. Some of the old but essential agricultural practices and livestock feed techniques are revived and discussed. Agricultural GHG mitigation approaches discussed in this work can serve as game changers in the attempt to reduce GHG emissions and alleviate the impact of climate change through sustainable agriculture and informed decision-making.

Quantifying synergies and trade-offs in the food-energy-soil-environment nexus under organic fertilization

Recycling livestock manure in agroecosystems can maintain crop production, improve soil fertility, and reduce environmental losses. However, there has been no comprehensive assessment of synergies and trade-offs in the food-energy-soil-environment nexus under manure application. Here, we evaluate the sustainability of maize production under four fertilization regimes (mineral, mineral and manure mixed, manure, and no fertilization) from the aspect of food security, energy output, soil quality, and environmental impact based on a five-year field experiment. Manure and mineral mixed fertilization maintained grain and straw quantity and quality compared with mineral fertilization. Manure and mineral mixed fertilization increased stem/leaf ratio and field residue index by 9.1–28.9% and 4.5–17.9%, respectively. Manure also maintained the theoretical ethanol yield but reduced the straw biomass quality index by increasing ash. Further, manure application increased the soil quality index by 40.5% and reduced N2O emissions by 55.0% compared with mineral fertilization. Manure application showed the highest sustainability performance index of 19, followed by mineral (15), mixed (13), and without fertilization (8). In conclusion, manure application maintains food production and energy output, enhances soil quality, and reduces environmental impact, thereby improving the sustainability of maize production.

Self-cleaning paper-based microfluidic biosensor employing DNAzyme and semiconducting single-walled carbon nanotube for copper ion detection

Microfluidic paper-based analytical device (μPAD) offers a simple and efficient platform for point-of-care monitoring, which can be beneficial for copper determination in livestock feed and manure. However, common cellulose paper has excellent hydrophilicity, causing μPAD is accompanied by poor mechanical properties, short service life, and low sensitivity. Here, a self-cleaning paper-based microfluidic biosensor for Cu2+ determination was proposed to overcome the mentioned shortages in the application. Polymeric octadecyl trichlorosilane was synthesized and decorated on cellulose paper to form hydrophobic paper, which can improve the hydrophobicity, self-cleaning, and pollution ability. In addition, hydrophobic paper, semiconducting single-walled carbon nanotube, and DNAzyme through the chemical bond were employed to fabricate a self-cleaning paper-based microfluidic biosensor. The properties were investigated using scanning electron microscopy, Raman, and electrochemical methods. The detecting parameters were also optimized. It could measure the Cu2+ concentration from 1 nM to 100 μM, and the detection limit was 0.65 nM. The self-cleaning paper-based microfluidic biosensor was applied to detect Cu2+ concentration in livestock feed and manure that can meet the requirements for fast screening and detection.

Sustainable agricultural management: How to achieve carbon neutrality in agriculture – evidence from China agricultural sustainable development plan

AbstractAgricultural sustainable development is of significant importance for achieving food security, environmental protection, climate change adaptation, natural resource conservation, and economic development. We conducted a study using the 2015 China Agricultural Sustainable Development Plan (ASDP) as a natural experiment and employed the Difference‐in‐Differences (DID) model to estimate the impact of ASDP on agricultural carbon neutrality. Path analysis and heterogeneity analysis were also performed. The results of this study are as follows: First, ASDP promotes agricultural carbon neutrality. Second, increasing per capita agricultural machinery usage, agricultural labor efficiency, livestock manure management, wastewater and waste treatment capacity, toilet coverage rate, greening efforts, and reducing pesticide usage are potential pathways of ASDP. Third, the analysis of carbon emission types indicates that current ASDP mainly focuses on carbon emissions from traditional agricultural practices, with limited impact on carbon emissions associated with modern agricultural activities, such as diesel fuel and pesticides. Lastly, the heterogeneity analysis of agricultural regions demonstrates that ASDP has a more positive impact on grain, oil, fruit and vegetable low‐producing areas, cotton high‐producing areas, and poultry, meat, eggs and milk aquaculture high‐producing areas. This study estimates the carbon reduction effect of ASDP and provides new policy recommendations and reform directions for agricultural sustainable development in China and other developing countries.

Separated two-stage hydrothermal liquefaction of livestock manure for high-quality bio-oil with low-nitrogen content: Insights on nitrogen migration and evolution

The practical utilization of hydrothermal liquefaction (HTL)-derived bio-oil encounters limitations due to its high nitrogen (N) content, specifically when derived from protein-rich feedstock such as algae and livestock manure. In this study, a separated two-stage HTL (ST-HTL) was developed for producing bio-oil with high yield and low N-content. The main objective of this study was to reveal the N migration and evolution during the HTL process for a better understanding of the detailed mechanism. The separated two-stage HTL yielded the highest bio-oil, 32.90 wt%, with a maximum energy recovery of 68.47 %. In conventional HTL-derived bio-oil (280 °C), 38.85 % of N and 56.22 % of C (carbon) was transferred to the bio-oil, while 26.04 % of N and 61.34 % of C (carbon) in swine manure was transferred into the ST-HTL-derived bio-oil, which indicated a 32.83 % reduction in N-transfers and 8.35 % increase in C-transfers. GC–MS analysis revealed that the bio-oil from ST-HTL contained a higher proportion of fatty acids and a lower proportion of nitrogenous compounds compared to conventional HTL (280 °C). In addition, FT-ICR MS revealed that the ST-HTL-derived-bio-oil was more saturated than conventional HTL-derived bio-oil (280 °C). The underlying mechanism behind the increased bio-oil yield and reduced N content attained through ST-HTL are discussed in detail, thereby revealing its intrinsic merits. Thus, it is the first study to propose the N migration and evolution pathways during ST-HTL through detailed characterizations, thus, demonstrating its potential for improving the feasibility of processing high-protein livestock manure and promising practical applications.

Pengomposan Tandan Kosong Kelapa Sawit yang Ditambahkan Berbagai Jenis Kotoran Hewan Ternak dan Penentuan Kualitas Kimia Bokashi Berbasis Standar Nasional Indonesia

Oil palm empty fruit bunch (OPEFB) is a large amount of palm oil industry waste and has the potential to be used as bokashi fertilizer with the addition of livestock manure to enrich its nutrient content. This study aims to determine the chemical quality of OPEFB bokashi by adding each chicken, cow, and goat manure based on the quality standards of organic fertilizer INS-19-7030-2004. The research was conducted from June to August 2022 in Tanah Bumbu Regency, South Kalimantan, and the Soil Laboratory of the Department of Soils, Faculty of Agriculture, Lambung Mangkurat University, Banjarbaru, South Kalimantan. This study used a quantitative method (nutrient analysis in the laboratory). The following treatments were used: K0 = OPEFB without adding livestock manure, K1 = OPEFB with adding chicken manure, K2 = OPEFB with adding cow manure, and K3 = OPEFB with the addition of goat manure. The results showed that treatment K1 (bokashi OPEFB with chicken manure) had better chemical quality than treatments K0, K2, and K3, namely parameters organic C (13,72%), total N (0.92%), C/N ratio (14.91%), total P (1.00%), total K (0.60%), total Ca (6.56%), and total Fe (0.02%). However, the total Mg parameter in the K1 treatment was 1.36% above the maximum SNI limit, and the pH parameters in all treatments (K0 4.91, K1 5.89, K2 4.59, and K3 5.05) were not in accordance with SNI-19-7030-2004.

Impact of livestock industry on climate change: Case Study in South Korea - A review.

In recent years, there has been a growing argument attributing the primary cause of global climate change to livestock industry, which has led to the perception that the livestock industry is synonymous with greenhouse gas (GHG) emissions. However, a closer examination of the global GHG emission by sector reveals that the energy sector is responsible for the majority, accounting for 76.2% of the total, while agriculture contributes 11.9%. According to data from the Food and Agriculture Organization of the United Nations (FAO), the total GHG emissions associate with the livestock supply chain amount to 14.5%. Within this, emissions from direct sources, such as enteric fermentation and livestock manure treatment, which are not part of the front and rear industries, represent only 7%. Although it is true that the increase in meat consumption driven by global population growth and rising incomes, has contributed to higher methane (CH4) emissions resulting from enteric fermentation in ruminant animals, categorizing the livestock industry as the primary source of GHG emissions oversimplifies a complex issue and disregards objective data. Therefore, it may be a misleading to solely focus on the livestock sector without addressing the significant emissions from the energy sector, which is the largest contributor to GHG emissions. The top priority should be the objective and accurate measurement of GHG emissions, followed by the development and implementation of suitable reduction policies for each industrial sector with significant GHG emissions contributions.

Screening and combination selection of multifunctional actinomycetes for aerobic composting.

To screen the most effective combination of multipurpose actinomycete strains for aerobic composting, lignocellulose-degrading strains were obtained through enrichment culture, separation and purification, and multiselection culture. The isolated strains were identified on the basis of morphology and 16S rRNA gene sequencing and comparison. The obtained actinomycetes were screened for the lignocellulose degradation rate, ammonia and hydrogen sulfide removal rate, and cellulase activity. Subsequently, a combination of strains with ecological coordination and complementary functions was determined through antagonistic tests. The combined strains were subjected to a straw fermentation test to evaluate their degradation effect. As a result, 20 strains of actinomycetes were isolated and identified from more than 56 samples from different sources, including 18 strains of Streptomyces sp. and 2 strains of Nocardiopsis sp. After a number of screenings, eight strains of actinomycetes with strong function were obtained. From the results of function and antagonistic tests, strains A3, A7, A8, A11, and A16 were selected to form consortia. The straw fermentation test showed that the lignocellulose degradation rate of the strain combination was as high as 39.8%, which was significantly higher than that of eachevery single strain (P < 0.05). The screened multifunctional actinomycete strains and their combination enriched the actinomycete germplasm resources used for microbial enhanced aerobic composting.IMPORTANCEWith the development of animal husbandry in China, the production of a large amount of livestock and poultry manure has become one of the main agricultural pollution sources. High-temperature aerobic composting stands out as one of the most crucial methods for the safe and resourceful utilization of livestock and poultry manure, serving as an essential link between crop cultivation, animal breeding, and sustainable agricultural development. Numerous studies have demonstrated that the addition of exogenous multifunctional bacterial agents to compost reduces not only harmful emissions but also sequesters or increases essential nutrients. However, these efficacies depend on the specific functions of the bacteriophage itself, the harmonization and complementarity within the colony, and its ability to adapt to the environment. In recent years, relatively few studies have been conducted on actinomycetes. This experiment provides excellent actinomycete resources for the production of high-efficiency and high-quality compost compound microbial agents of manure and straw.

Review and Bibliometric Analysis of Biogas Power Plants in Indonesia

The demand for energy is increasing due to population growth, technological advancements, and a growing need for sustainable energy sources. Indonesia, which faces an energy deficit, is exploring alternatives to fossil fuels. Biogas, produced through the anaerobic fermentation of organic matter, offers a clean and sustainable energy option while addressing waste disposal issues. Therefore, this literature review examines various aspects of a biogas power plant, including a feasibility study that encompasses technical and economic analyses, generator design, trials, implementation, and post-implementation evaluation. In this review, we gathered scientific papers from Google Scholar using the keywords "pembangkit listrik biogas" between 2019 and 2022, with a focus on recent content. Patents and citations were excluded from the Google Scholar searches to ensure article relevance. Out of a total of 40 articles, 30 were rejected because they did not originate from scientific journals. The collected articles are categorized based on the materials used for biogas generation in power plants. This systematic approach yielded 10 relevant articles. Consequently, the literature reveals that various raw materials, such as palm oil mill waste (POME), livestock manure, and organic waste, hold the potential for biogas production. The results emphasize the economic feasibility of specific biogas projects, the environmental challenges they pose, and the positive impact they have on community well-being