Biogas Fermentation Research Articles

Performance Monitoring of Greenhouse Biogas Digester

The country of South Africa is facing an energy crisis due to heavy reliance on fossil fuels, resulting in continuous load shedding. The use of renewable energy technologies can help resolve the current electricity crisis in the country. Moreover, waste-to-energy conversion has the potential to greatly contribute to economic development and improve public health. One such technology is biomass, which exploits waste-to-energy conversion. Additionally, solar energy can be utilized to maintain appropriate digester temperatures for optimal biogas yield. The study aims to assemble a portable balloon biogas digester in an enclosed greenhouse cavity and feed it with cow dung. Daily monitoring of pH and temperature (ambient, greenhouse, and slurry) was conducted, while biogas yield was monitored using a serial residential diaphragm flow meter. Furthermore, the composition of methane was monitored using the SAZQ biogas analyzer. The study investigated the impact of temperature on biogas production. The results revealed that the gas production rate of biogas fermentation increased within a certain temperature range. Therefore, maximum biogas production was achieved at a pH of 6.84 to 7.03, and the composition of methane exceeded 50%. Consequently, the study concluded by indicating that the digester housed within a greenhouse envelope, as demonstrated in this novel study, maintains the temperature within the optimal mesophilic range necessary for anaerobic digestion.

Biochar derived from biogas fermentation residue with enhanced absorption property suitable for efficient absorption of methylene blue in aqueous

The biochar produced from pyrolysis of corn stove biogas fermentation residues was used for methylene blue adsorption in aqueous solution. The effects of fermentation time (0, 20,40 d) and the highest treatment temperature (HTT) from 400 to 600 °C on biochar properties and methylene blue adsorption characteristics were investigated. Biochar produced from corn stover was used as control. The result shows that biochar from fermentation residue got a higher yield, larger specific surface area, significantly more attachment particles and surface functional groups than that from corn stover. The specific surface area of biochar increased apparent with the increasing fermentation time of corn stover. However, the microporous specific surface (Smicro) decreased from 3.7558 to 1.9818 m2•g−1, while mesoporous specific surface (Smeso) increased from 1.9901 to 3.8994 m2•g−1. The methylene blue adsorption capacity increased with increasing pH value from 2 to 12. The maximum removal rate of methylene blue increased from 86.8 % to 98.64 % when the BC-F20 loading (produced at 400 °C) increased from 0.3 to 1.2 g, while the equilibrium adsorption capacity of methylene blue decreased from 28.94 to 8.22 mg/g. In addition, the adsorption capacity of biochar decreased as HTT increased from 400 to 600 °C. The results indicate that biochar derived from biogas fermentation residue has enhanced the absorption capacity for methylene blue in aqueous solution

How Fluid Pseudoplasticity and Elasticity Affect Propeller Flows in Biogas Fermenters

AbstractMixing in biogas fermenters is complex due to the non‐Newtonian rheology of biogenic substrates, which exhibit both pseudoplasticity and elasticity. It is yet unclear how these non‐Newtonian properties affect propeller flows and the mixing behavior in fermenters. Therefore, propeller flows in Newtonian as well as shear‐thinning inelastic and elastic fluids are compared numerically and validated against particle image velocity (PIV) data. Elastic normal stresses lead to an increase of pumping rates in the laminar regime and a suppression of the formation of a propeller jet in the transitional regime. Thus, flow rates are severely overestimated by the inelastic, shear‐thinning model in this regime. The results indicate that elasticity is critical for an accurate modeling of flows of biogenic substrates.

Comparative genomic analysis of an emerging Pseudomonadaceae member, Thiopseudomonas alkaliphila.

Thiopseudomonas alkaliphila, an organism recently classified within the Pseudomonadaceae family, has been detected in diverse sources such as human tissues, animal guts, industrial fermenters, and decomposition environments, suggesting a diverse ecological role. However, a large knowledge gap exists in how T. alkaliphila functions. In this comparative genomic analysis, adaptations indicative of habitat specificity among strains and genomic similarity to known opportunistic pathogens are revealed. Genomic investigation reveals a core metabolic utilization of multiple oxidative and non-oxidative catabolic pathways, suggesting adaptability to varied environments and carbon sources. The genomic repertoire of T. alkaliphila includes secondary metabolites, such as antimicrobials and siderophores, indicative of its involvement in microbial competition and resource acquisition. Additionally, the presence of transposases, prophages, plasmids, and Clustered Regularly Interspaced Short Palindromic Repeats-Cas systems in T. alkaliphila genomes suggests mechanisms for horizontal gene transfer and defense against viral predation. This comprehensive genomic analysis expands our understanding on the ecological functions, community interactions, and potential virulence of T. alkaliphila, while emphasizing its adaptability and diverse capabilities across environmental and host-associated ecosystems.IMPORTANCEAs the microbial world continues to be explored, new organisms will emerge with beneficial and/or pathogenetic impact. Thiopseudomonas alkaliphila is a species originally isolated from clinical human tissue and fluid samples but has not been attributed to disease. Since its classification, T. alkaliphila has been found in animal guts, animal waste, decomposing remains, and biogas fermentation reactors. This is the first study to provide an in-depth view of the metabolic potential of publicly available genomes belonging to this species through a comparative genomics and draft pangenome calculation approach. It was found that T. alkaliphila is metabolically versatile and likely adapts to diverse energy sources and environments, which may make it useful for bioremediation and in industrial settings. A range of virulence factors and antibiotic resistances were also detected, suggesting T. alkaliphila may operate as an undescribed opportunistic pathogen.

Experimental study on biogas fermentation of corn stover pretreated with compound microbial agent

This research investigates the potential of corn stover, an agricultural byproduct, as a biomass energy source to help solve energy challenges. We introduced a compound microbial agent (CMA) to treat corn stover, consisting of five strains adept at degrading lignocellulose. The pretreatment's effectiveness was gauged by tracking shifts in pH and Chemical Oxygen Demand (COD). The corn stover's morphological and chemical changes were scrutinized using a Scanning Electron Microscope (SEM), X-ray diffractometer (XRD), and Fourier Transform Infrared Spectrometer (FTIR). Throughout the biogas fermentation phase, Pretreated Corn Stover (PCS) outperformed Unpretreated Corn Stover (UCS) in terms of lignocellulose degradation, total solids (TS) elimination, and volatile solids (VS) elimination. The fermentation process induced fluctuations in volatile fatty acids (VFAs) and gas composition for both PCS and UCS. Significantly, PCS generated 4236.78 mL more biogas and 3358.31 mL more CH4 compared to UCS. The study's CMA pretreatment strategy significantly enhanced the methane conversion rate and biogas yield, providing a sustainable approach to harnessing agricultural waste in the energy sector. The results highlight CMA's capacity to increase biogas and CH4 production, showcasing its promise in tackling energy needs through the efficient transformation of biomass.

IMPLEMENTATION OF BIOGAS EQUIPMENT USING ARDUINO MEGA 2560 WITH SENSOR MQ-4

The biogas in the research that the authors do is a mixture of cow dung with 1: 2 water, where the biogas in this study is carried out by anaerobic fermentation or without air, a mixture of cow dung and water is put into the reactor and the fermentation process is carried out for 12 days to prove whether biogas In this study, gas will be stored in storage (biogas bag 1 and biogas bag 2. The research method used, namely conducting literature studies, exploration, determining equipment specifications, designing and implementing and testing. In designing this tool, it is able to produce gas from the biogas fermentation process, namely methane gas which can be detected by a functioning methane gas sensor. Where there is an increase in PPM testing between the first MQ-4 sensor from 5246.36 and the second MQ-4 sensor detected at 5667.23 PPM with the adjusted difference of 420.87 PPM, so the methane gas is tested with a stove and a lighter. The MQ-4 sensor measurement error results reached 5.63%. Keywords: Reaktor fixed dome, MQ-4, Gas Metana, Monitoring

Potential of Methane (CH4), Nitrogen (N2), and Carbon Dioxide (CO2) from Eco-Enzyme with the Addition of Cow Feces Starter

Eco-enzyme solutions are generally used in the manufacture of disinfectants, floor cleaners, liquid fertilizers, preservatives and others. In this study, eco-enzyme was used as the main ingredient in the manufacture of biogas fermentation with the addition of cow feces as an additional starter in the fermentation. The aim of this study was to determine the content of CH4, CO2, N2, pH, temperature, and pressure in eco-enzyme fermentation with the addition of cow feces starter. his research is a quantitative research with the type of experimental research as well as direct observation data collection techniques and data analysis techniques using descriptive statistical analysis. The results showed that the treatment that produced the highest methane (CH4) gas was the P5 treatment with a concentration of 2.889%. 6,1. The highest volume pressure value was produced in the P5 treatment which was 70 ml. Nitrogen gas (N2) and carbon dioxide gas (CO2), the concentration of nitrogen gas (N2) from reactor P0 - P4 is in the range of 95.875-99.669 % and the concentration of carbon dioxide (CO2) from reactor P0 - P4 is in the range of 0.237 - 4.125 %.

The Impact of Biostarter Em-4 and Buffalo Feces on The Quality of Biogas Created from Sugarcane Bagasse Fiber

Energy is one of the most important needs in life. That’s because all human activities require energy to live. New breakthroughs need to be made to overcome the energy crisis, one of which is biogas by utilizing waste. Waste that can be used is sugarcane bagasse and buffalo feces, which have the potential to produce biogas. The purpose of this study was to determine the effect of a mixture of bagasse fiber and buffalo manure with the addition of EM-4 biostarter and without EM-4 biostarter that has the potential to produce biogas. Variations in the composition of AT and buffalo feces in this study were 50%SB: 50%BF, 40%SB:60%BF and 30%SB:70%BF without using the EM-4 biostarter. batch-type digester reactor type. The method used is the experimental method. The results showed that biogas production from the composition of a mixture of bagasse fiber with buffalo feces has an influence. Where the more buffalo feces added, the more gas produced. Then for the biogas production process using EM-4 biostarter and without EM-4 biostarter, it was found that the best in producing gas was using EM-4 biostarter, this was due to the function of biostarter which accelerates biogas fermentation so that the influence on biogas production was to use EM-4 biostarter

Mitigated CH4 release of anaerobic waste fermentation is enabled through effluent degassing system equipped with a polydimethylsiloxane membrane contactor

In this study, first, a fed-batch biogas fermenter was established using anaerobic digester sludge treating secondary sludge from a municipal wastewater treatment plant and operated for 120 days on glycerol as the sole substrate. Then, the prefiltered effluent of the anaerobic digester unit was loaded subsequently into a stirred-tank coupled with a hollow-fibre, polydimethylsiloxane (PDMS) gas-liquid membrane contactor and a dissolved methane sensor for studying the gas recovery process under continuous biogas supply, consisting of CH4 and CO2 in different proportions (70/30 CH4/CO2 vol.%; 50/50 CH4/CO2 vol.%; 30/70 CH4/CO2 vol.%.). Experiments showed that besides the actual composition of the internal biogas, the ratio (0.5–2) of sweep gas (N2) and effluent (liquid) volumetric flow rates (G/L) could be a crucial operating factor with influence on the degassing efficiency attainable by the 1 m2 PDMS membrane module. Results were compared to the performance of the same PDMS membrane module working with synthetic anaerobic digester effluents, indicating the dissolved methane recoveries observed with the synthetic effluents (>50 %) considerably surpassed those with the real effluent (<20 %) where the dissolved methane concentrations, at G/L of 1, were in the range of 12.4 to 17.3 mg L−1.

Biogas Production in a Variety of Sawdust and Cow Dung Mixtures Using the Intermittent Mixing Method

Cow dung is livestock waste that is very useful for renewable energy sources. The acceleration of the gas rate in cow dung biogas fermentation can be accelerated by the addition of secondary material, sawdust is one of the organic materials that can accelerate the rate of gas production in the formation of cow dung biogas. This study used a mixture composition: (B1) 675 g cow dung and 0 g sawdust, (B2) 472.5 g cow dung and 202.5 sawdust, (B3) 450 g cow dung and 225 g sawdust, and (B4) 427.5 g cow dung and 247.5 g of sawdust by fermentation for 20 days. In the research process, measurements of pH at the beginning and at the end of the study, gas pressure, gas volume, biodigester temperature, production rate, methane gas content, and flame test were carried out. In this study, the pH values ranged from 7-7.5 and the biodigester temperature was 27.5-31°C. The results of this study indicate that an organic mixture with a mixture of sawdust can accelerate production faster than without organic sawdust. Optimal results are found in the variation of the organic mixture of sawdust with a mixture of 450 g cow dung and 250 g sawdust having the highest production rate of 281.72 ml/day.

THE ROLE OF BACTERIAL AND ARCHAEA IN DETERMINING THE METABOLIC PATHWAY OF BIOGAS FERMENTATION AT LOW TEMPERATURES

The challenge in achieving large-scale biogas production still lies in the biogas fermentation process at low temperatures. Our goal was to delve into the metabolic pathway behind the formation of biogas at these lower temperatures, focusing on the dominant bacterial and archaeal communities. Employing a batch system with activated sludge inoculum at 10°C, we fermented cow manure at 12°C for 150 days. Through genetic sequencing and taxonomic analysis using OTUs from the 16S rDNA gene, we investigated bacterial and archaeal species. Correlation analysis between their abundance was conducted using Pearson correlation and t-tests via IBM SPSS Statistics. Our findings revealed a biogas production of around 0.74 L/day, with CH4 levels surpassing 0.45 L/g VS. Peak efficiency occurred between day 60 and 110, reaching its apex on day 90. Clostridium cellulovorans dominated, ranging from 13.9% to 27%, followed by Terrisporobacter petrolarius, around 16.2% to 23%. Specifically, the formation of biogas (CH4) predominantly occurred through the H2 pathway, led by significant hydrogenotrophic Archaea OTUs like Methanocorpusculum sinense (ranging from 4.95% to 37.10%) and Methanobrevibacter millerae (with relative abundances between 2.00% and 11.20%)

Spatial distribution and influencing factors of China's household biogas: evidence from provincial-level data.

To address the adjustment of the Chinese agricultural industry and to better promote the development of Chinese household biogas, this article summarizes and analyzes the spatial distribution characteristics and influencing factors of the type and number of biogas digesters, biogas production, biogas fermentation materials, and methods of fermentation residue utilization and ecological agriculture with household biogas by compiling a dataset covering 31 provincial administrative regions in China. The results show that hydraulic biogas digesters are distributed mainly in northwestern and northeastern China; in addition, continuously stirred biogas digesters and bottom-discharging biogas digesters are distributed mainly in southern and northern China, respectively. Because of temperature and population, the Sichuan and Henan Provinces have the highest number of biogas digesters and biogas production. The type of biogas fermentation materials depends on the local raw materials. Biogas slurry and residue are widely used as fertilizers; furthermore, biogas slurry is used for seed soaking in northeastern and southern China, and biogas residue is used as feed in central southern and northern China. The "Three-in-one" and "Four-in-one" biogas ecological models are used mostly in southern and northern China, respectively, and both are mainly affected by temperature. Finally, we propose various problems and countermeasures to enhance the development of the household biogas industry in China. Our findings are critical for China's policymakers to adopt effective measures for promoting the development of cleaner energy and the layout of the agricultural industry.

Simplicity Hits the Gas: A Robust, DIY Biogas Reactor Holds Potential in Research and Education in Bioeconomy

Biogas is a promising and robust renewable energy that holds potential as clean energy in the context of the current climatic emergency. Biogas has the immense advantage of coupling waste management and clean energy production. In other words, it is not only a renewable energy source, but also a central tool in recycling a vast range of waste products from the agroindustry. Despite its potential, the process is microbiologically complex and is usually carried out in both industrial and pilot laboratories, utilizing a variety of reactors and systems. In this work, we present a very simple, Do It Yourself (DIY) biogas fermenter that we have designed, operated, and characterized. We propose this technology as both an inexpensive proxy for biogas reactors in academic and private laboratories and as an effective dissemination tool to foster the knowledge and potential of biogas as a key technology to contribute to the development of a global bioeconomy.

Inter-Zone Optimal Scheduling of Rural Wind–Biomass-Hydrogen Integrated Energy System

To solve the problems of low utilization of biomass and uncertainty and intermittency of wind power (WP) in rural winter, an interval optimization model of a rural integrated energy system with biogas fermentation and electrolytic hydrogen production is constructed in this paper. Firstly, a biogas fermentation kinetic model and a biogas hydrogen blending model are developed. Secondly, the interval number is used to describe the uncertainty of WP, and an interval optimization scheduling model is developed to minimize daily operating cost. Finally, a rural integrated energy system in Northeast China is taken as an example, and a sensitivity analysis of electricity price, gas production, and biomass price is conducted. The simulation results show that the proposed strategy can significantly reduce the wind abandonment rate and improve the economy by 3.8–22.3% compared with conventional energy storage under optimal dispatch.

Anaeropeptidivorans aminofermentans gen. nov., sp. nov., a mesophilic proteolytic salt-tolerant bacterium isolated from a laboratory-scale biogas fermenter, and emended description of Clostridium colinum.

An anaerobic bacterial strain, designated strain M3/9T, was isolated from a laboratory-scale biogas fermenter fed with maize silage supplemented with 5 % wheat straw. Cells were straight, non-motile rods, which stained Gram-negative. Optimal growth occurred between 30 and 40°C, at pH 7.5-8.5, and up to 3.9 % (w/v) NaCl was tolerated. When grown on peptone from casein and soymeal, strain M3/9T produced mainly acetic acid, ethanol, and isobutyric acid. The major cellular fatty acids of the novel strain were C16 : 0 and C16 : 0 DMA. The genome of strain M3/9T is 3757 330 bp in size with a G+C content of 38.45 mol%. Phylogenetic analysis allocated strain M3/9T within the family Lachnospiraceae with Clostridium colinum DSM 6011T and Anaerotignum lactatifermentans DSM 14214T being the most closely related species sharing 57.86 and 56.99% average amino acid identity and 16S rRNA gene sequence similarities of 91.58 and 91.26 %, respectively. Based on physiological, chemotaxonomic and genetic data, we propose the description of a novel species and genus Anaeropeptidivorans aminofermentans gen. nov., sp. nov., represented by the type strain M3/9T (=DSM 100058T=LMG 29527T). In addition, an emended description of Clostridium colinum is provided.

Compost Fertilization in Organic Agriculture—A Comparison of the Impact on Corn Plants Using Field Spectroscopy

To protect the environment and reduce the impact of fertilizing on climate change, a tailored fertilization according to the needs of the plants becomes more and more important. In organic farming, the main sources of nitrogen (N) are organic fertilizers, such as compost and farmyard manure. In conventional agricultural systems, various plant sensors have already proven that they can guide efficient fertilization. Since these sensors can record the growth of the biomass growth, they can also be used in organic farming to detect the influence of various organic fertilizers on the growth of corn plants. In a field trial established in 2017, eight different organic fertilizers (biogas fermentation residue, matured farmyard manure, fresh and matured organic waste compost, fresh and matured green compost, and microbial carbonized compost) were used and applied in two different amounts (120 and 240 kg N ha−1) along with an unfertilized control variant. The fertilization was applied according to the current version of the German fertilizer ordinance. In 2021, sensor measurements of the corn plants were taken at six different stages of development (from BBCH 13 to BBCH 35) with a hand-held field spectrometer using the REIP vegetation index. The measurements showed that the unfertilized control variant could be reliably recorded. Furthermore, even at early growth stages the measurements showed the differences between different composts. The results presented in this study show that sensor measurements using vegetation indices reacted sensitively to organic fertilization and can be a tool for farmers to support their decision for an adequate fertilization strategy.

The temperature and pressure Remote intelligent control system for biogas digester based on STM32

The application of biogas digesters in modern life has become more and more extensive. However, the current level of automation in biogas management was too low. and people are afraid of odor and dirty when operating biogas fermentation. In order to solve the shortage of modern energy and improve the safety and efficiency of biogas digesters, a temperature and pressure remote intelligent control management system based on STM32 for biogas digesters was designed. This system took STM32 as the main control chip, through the DS18B20 and PMS pressure measurement module for temperature and pressure measurement, combined with ESP 8266 01sWiFi module and cloud platform for data transmission communication and storage, and then displayed to the user by the QT software interface, the remote intelligent control of the biogas digester in the cloud was realized, so that the efficiency and safety management of the biogas digester were could improved. This management system of the biogas digester would promote the energy industry and sustainable development of human beings and facilitated rural revitalization.

Effects of environmental factors on low temperature anaerobic digestion of pig manure

In this study, we investigated the inhibitory effect of low temperature on biogas fermentation system. Biogas fermentation inoculum was domesticated at 4 °C, and subsequently inoculated into pig manure feedstock in a batch biogas fermentation process. A low-temperature biogas fermentation system was maintained at 9 °C, and its abiotic factors, bacterial community, and archaeal community were determined. The results showed that (1) the biogas fermentation lasted for 160 days, with a total gas production of 19,150 ml, including N2 production of 11,370 ml, CO2 production of 3,534 ml, and CH4 production of 3,031 ml. (2) The average relative abundance of the primary dominant bacterium operational taxonomic unit (OTU) was 30%, with 100% similarity to Pseudomonas caeni , atypical denitrifying bacterium. The average relative abundance of the secondary dominant bacterium OTU was 20.36%, with 99% similarity to Clostridium cellulovorans, a typical cellulose- and hemicellulose-degrading bacterium. The average relative abundance of the primary dominant methanogenic archaeon OTU was 7.22%, with 99% similarity to Methanosphaera cuniculi, a typical methylotrophic methanogen, and the secondary dominant methanogenic archaeon OTU had an average relative abundance of 4.15%, with 98% similarity to Methanocorpusculum sinense, a typical hydrogenotrophic methanogen. (3) The primary dominant bacterial genus Pseudomonas exhibited highly significant negative correlations with the dominant biogas-producing microorganisms such as Clostridium, Terrisporobacter, Turicibacter, Methanosphaera, and Methanocorpusculum. We concluded that (1) high concentrations of abiotic factors such as ammonia nitrogen, acetic acid, and propionic acid were important indicators of relatively poor operation of low-temperature biogas fermentation systems, while (2) high numbers of MCG archaea and Pseudomonas were important biotic factors showing comparatively poor operation of the system.

Arabinan saccharification by biogas reactor metagenome-derived arabinosyl hydrolases

BackgroundPlant cell walls represent the most plentiful renewable organic resource on earth, but due to their heterogeneity, complex structure and partial recalcitrance, their use as biotechnological feedstock is still limited.ResultsIn order to identify efficient enzymes for polysaccharide breakdown, we have carried out functional screening of metagenomic fosmid libraries from biogas fermenter microbial communities grown on sugar beet pulp, an arabinan-rich agricultural residue, or other sources containing microbes that efficiently depolymerize polysaccharides, using CPH (chromogenic polysaccharide hydrogel) or ICB (insoluble chromogenic biomass) labeled polysaccharide substrates. Seventy-one depolymerase-encoding genes were identified from 55 active fosmid clones by using Illumina and Sanger sequencing and dbCAN CAZyme (carbohydrate-active enzyme) annotation. An around 56 kb assembled DNA fragment putatively originating from Xylanivirga thermophila strain or a close relative was analyzed in detail. It contained 48 ORFs (open reading frames), of which 31 were assigned to sugar metabolism. Interestingly, a large number of genes for enzymes putatively involved in degradation and utilization of arabinose-containing carbohydrates were found. Seven putative arabinosyl hydrolases from this DNA fragment belonging to glycoside hydrolase (GH) families GH51 and GH43 were biochemically characterized, revealing two with endo-arabinanase activity and four with exo-α-l-arabinofuranosidase activity but with complementary cleavage properties. These enzymes were found to act synergistically and can completely hydrolyze SBA (sugar beet arabinan) and DA (debranched arabinan).ConclusionsWe screened 32,776 fosmid clones from several metagenomic libraries with chromogenic lignocellulosic substrates for functional enzymes to advance the understanding about the saccharification of recalcitrant lignocellulose. Seven putative X. thermophila arabinosyl hydrolases were characterized for pectic substrate degradation. The arabinosyl hydrolases displayed maximum activity and significant long-term stability around 50 °C. The enzyme cocktails composed in this study fully degraded the arabinan substrates and thus could serve for arabinose production in food and biofuel industries.

A Review of Solar Energy Use in Biogas Digester Heating

Abstract: Several factors affect biogas fermentation, among which the temperature fluctuation is crucial. Domestic and foreign biogas fermentation heating systems are also diverse. Among various exist methods of heating biogas fermentation, solar biogas fermentation heating systems are also diverse. The current study reviewed various solar-heating biogas fermentation systems at home and abroad, describing the principle of the solar-heating system, the collector, the heat storage material and the research and application progress. It briefly discussed its characteristics, summarising the critical technology of solar biogas heating systems.