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Waste Management & Research : the... Aug 2022Traditionally, digestate is considered a waste, which is used as fertiliser in the agriculture industry. Recent studies focus on increasing the profitability of... (Review)
Review
Traditionally, digestate is considered a waste, which is used as fertiliser in the agriculture industry. Recent studies focus on increasing the profitability of digestate by extracting reusable nutrients to promote biogas plants cost-effectiveness, sustainable management and circular economy. This review focuses on the post-treatment and valorization of liquor which is produced by solid-liquid fractioning of digestate. Nutrient recovery and removal from liquor are possible through mechanical, physicochemical and biological procedures. The processes discussed involve complex procedures that differ in economic value, feasibility, legislative restrictions and performance. The parameters that should be considered to employ these techniques are influenced by liquor characteristics, topography, climate conditions and available resources. These are key parameters to keep in mind during designing and manufacturing a biogas plant. In the following chapters, a discussion on available liquor treatment methods takes place. The present study examines the critical aspects of the available liquor treatment methods.
Topics: Agriculture; Anaerobiosis; Biofuels; Fertilizers
PubMed: 35057678
DOI: 10.1177/0734242X211073000 -
International Journal of Molecular... Dec 2023Plant waste biomass is the most abundant renewable energy resource on Earth. The main problem with utilising this biomass in anaerobic digestion is the long and costly... (Review)
Review
Plant waste biomass is the most abundant renewable energy resource on Earth. The main problem with utilising this biomass in anaerobic digestion is the long and costly stage of degrading its complex structure into simple compounds. One of the promising solutions to this problem is the application of fungi of the genus, which show a high capacity to produce hydrolytic enzymes capable of degrading lignocellulosic biomass before anaerobic digestion. This article discusses the structure of plant waste biomass and the problems resulting from its structure in the digestion process. It presents the methods of pre-treatment of lignocellulose with a particular focus on biological solutions. Based on the latest research findings, key parameters related to the application of sp. as a pre-treatment method are discussed. In addition, the possibility of using the digestate from agricultural biogas plants as a carrier for the multiplication of the sp. fungi, which are widely used in many industries, is discussed.
Topics: Anaerobiosis; Trichoderma; Biofuels; Biomass; Hydrolysis
PubMed: 38139408
DOI: 10.3390/ijms242417576 -
STAR Protocols Sep 2021The use of germ-free mice is integral to the understanding of host-gut microbiome relationships. Such models rely on faithful replication of the donor microbiome to...
The use of germ-free mice is integral to the understanding of host-gut microbiome relationships. Such models rely on faithful replication of the donor microbiome to establish causal effects of the gut microbiota on host pathophysiology. This protocol describes the preparation and transfer of donor microbiota, focusing on strict anaerobic processing methods and multiple instillations by gavage for optimal gut microbiota recovery. For complete details on the generation and use of this protocol, please refer to Choo and Rogers (2021).
Topics: Anaerobiosis; Animals; Bioreactors; Fecal Microbiota Transplantation; Germ-Free Life; Mice
PubMed: 34189475
DOI: 10.1016/j.xpro.2021.100610 -
Sheng Wu Gong Cheng Xue Bao = Chinese... Nov 2022Traditionally, amino acids are produced mainly by chemical synthesis or aerobic fermentation. Compared to chemical synthesis, production of amino acids by microbial...
Traditionally, amino acids are produced mainly by chemical synthesis or aerobic fermentation. Compared to chemical synthesis, production of amino acids by microbial fermentation directly uses renewable resources as feedstock and this reduces the dependence on petroleum-based compounds and decreases pollutants generation and toxic substrates usage. Fermentation under aerobic conditions has been used widely for its fast growth and high titers. However, a large amount of carbon is used for cell growth and this results in high biomass but low yield of target chemicals. Unlike the long history of aerobic fermentation, the commercial production of amino acids by anaerobic fermentation is realized only in recent years. It has several advantages such as simpler operation, no need for oxygen supply, and high yield close to the theoretical maximum value. L-alanine is the first amino acid commercially produced by anaerobic fermentation. In this article, we summarize the key technology for anaerobic fermentative production of L-alanine and its commercialization. As it is shown to be low-cost, high-efficiency, and environmental-friendly, anaerobic fermentation is expected to be widely used in industrial process and brings greater economic values and social benefits in the future.
Topics: Anaerobiosis; Fermentation; Alanine; Amino Acids; Technology
PubMed: 37699692
DOI: 10.13345/j.cjb.220594 -
Bioresource Technology Feb 2022In this study, a community-scale in-situ rapid biological reduction (IRBR) system was applied to achieve the rapid disposal and resource recovery of food waste (FW). A...
In this study, a community-scale in-situ rapid biological reduction (IRBR) system was applied to achieve the rapid disposal and resource recovery of food waste (FW). A total of 5263 kg FW was processed in the 35 days of stably operation, during which 84.37% total mass reduction and 43.30% volatile solid removal were achieved, and the odor had been effectively controlled. Microbial sequencing results showed that aerobic and facultative thermophilic bacteria were major bacterial community, and vigorous metabolism of both carbohydrate and amino acid were maintained during the IRBR process. The final products have the potential to be recycled as organic fertilizers or bio-solid fuel to realize resource recovery. The results of economic analysis showed that the IRBR system had lower FW disposal costs due to the high automation. These results suggested that the IRBR system was an environmentally friendly, economical and practical method for the FW rapid treatment.
Topics: Anaerobiosis; Food; Refuse Disposal
PubMed: 34953987
DOI: 10.1016/j.biortech.2021.126603 -
Waste Management (New York, N.Y.) Nov 2021The increase in anaerobic digestion systems has profoundly affected the waste management of territories, particularly for agricultural systems. Changes in cultural...
The increase in anaerobic digestion systems has profoundly affected the waste management of territories, particularly for agricultural systems. Changes in cultural practices and imports of organic waste modify the carbon (C) and nitrogen (N) fluxes on territories where anaerobic digestion is implemented. Successful anaerobic digestion can increase the economic and ecological efficiency of the waste management system. Conversely, poor anaerobic digestion leads to low economic and environmental efficiency due to greenhouse gas emissions and nutrient loss. Modeling the impact of anaerobic digestion on the systems integrating anaerobic digestion can improve the efficiency of these practices. The aim of this study was to develop, analyze, and evaluate a simple mass balance tool able to predict carbon and nitrogen fluxes in anaerobic digestion systems. The tool is composed of an exhaustive substrate database used by three models: (i) an anaerobic digestion model that predicts C and N contents in biogas and digestate; (ii) a phase separation model that predicts C and N content in liquid and solid phase digestates; and (iii) a storage model that predicts C and N content in raw, liquid phase, and solid phase digestates, as well as C and N emissions during storage. Sensitivity analyses were performed on the tool to determine critical inputs. Sensitivity analysis showed that outputs were highly sensitive to their respective inputs and to total inputs of solids. Performance evaluation showed that the tool can provide good quality predictions with R correlations between observation and prediction varying from 0.72 to 0.99 with the best predictions obtained for raw digestate.
Topics: Agriculture; Anaerobiosis; Biofuels; Carbon; Nitrogen
PubMed: 34474306
DOI: 10.1016/j.wasman.2021.08.020 -
Bioresource Technology Dec 2020Methanogenesis can be promoted by the addition of conductive materials. Although stimulating effects of conductive materials on methane (CH) production has been... (Review)
Review
Methanogenesis can be promoted by the addition of conductive materials. Although stimulating effects of conductive materials on methane (CH) production has been extensively reported, the crucial roles on recovering methanogenic activities under inhibitory conditions have not been systematically discussed. This critical review presents the current findings on the effects of conductive materials in methanogenic systems under volatile fatty acids (VFAs), ammonia, sulfate, and nano-cytotoxicity stressed conditions. Conductive materials induce fast VFAs degradation, avoiding VFAs accumulation during anaerobic digestion. Under high ammonia concentrations, conductive materials may ensure sufficient energy conservation for methanogens to maintain intracellular pH and proton balance. When encountering the competition of sulfate-reducing bacteria, conductive materials can benefit electron competitive capability of methanogens, recovering CH production activity. Conductive nanomaterials stimulate the excretion of extracellular polymeric substances, which can prevent cells from nano-cytotoxicity. Future perspectives about unraveling mitigation mechanisms induced by conductive materials in methanogenesis processes are further discussed.
Topics: Ammonia; Anaerobiosis; Electric Conductivity; Electrons; Fatty Acids, Volatile; Methane
PubMed: 32799079
DOI: 10.1016/j.biortech.2020.123977 -
Bioengineered Dec 2023A recently strategy applied to anaerobic digestion (AD) is the use of biochar (BC) obtained from the pyrolysis of different organic waste. The PRISMA protocol-based... (Review)
Review
A recently strategy applied to anaerobic digestion (AD) is the use of biochar (BC) obtained from the pyrolysis of different organic waste. The PRISMA protocol-based review of the most recent literature data from 2011-2022 was used in this study. The review focuses on research papers from Scopus® and Web of Knowledge®. The review protocol used permits to identify 169 articles. The review indicated a need for further research in the following challenges on the application of BC in AD: i) to increase the use of BC in developing countries, which produce large and diverse amounts of waste that are the source of production of this additive; ii) to determine the effect of BC on the AD of organic waste under psychrophilic conditions; iii) to apply tools of machine learning or robust models that allow the process optimization; iv) to perform studies that include life cycle and technical-economic analysis that allow identifying the potential of applying BC in AD in large-scale systems; v) to study the effects of BC on the agronomic characteristics of the digestate once it is applied to the soil and vi) finally, it is necessary to deepen in the effect of BC on the dynamics of nitrogen and microbial consortia that affect AD, considering the type of BC used. In the future, it is necessary to search for new solutions in terms of the transport phenomena that occurs in AD with the use of BC using robust and precise mathematical models at full-scale conditions.
Topics: Anaerobiosis; Agriculture; Machine Learning; Microbial Consortia
PubMed: 37712696
DOI: 10.1080/21655979.2023.2252191 -
Bioresource Technology Feb 2021Conductive materials can serve as biocatalysts during direct interspecies electron transfer for methanogenesis in anaerobic reactors. However, the mechanism promoting... (Review)
Review
Conductive materials can serve as biocatalysts during direct interspecies electron transfer for methanogenesis in anaerobic reactors. However, the mechanism promoting direct interspecies electron transfer in anaerobic reactors, particularly under environments in which diverse substrates and microorganisms coexist, remains to be elucidated from a scientific or an engineering point of view. Currently, many molecular microbiological approaches are employed to understand the fundamentals of this phenomenon. Here, the direct interspecies electron transfer mechanisms and relevant microorganisms identified to date using molecular microbiological methods were critically reviewed. Moreover, molecular microbiological methods for direct interspecies electron transfer used in previous studies and important findings thus revealed were analyzed. This review will help us better understand the phenomena of direct interspecies electron transfer using conductive materials and offer a framework for future molecular microbiological studies.
Topics: Anaerobiosis; Electric Conductivity; Electron Transport; Electrons; Methane
PubMed: 33358582
DOI: 10.1016/j.biortech.2020.124587 -
Environmental Science & Technology Feb 2023The combination of anaerobic digestion (AD) and microbial electrochemical technologies (METs) offers different opportunities to increase the efficiency and...
The combination of anaerobic digestion (AD) and microbial electrochemical technologies (METs) offers different opportunities to increase the efficiency and sustainability of AD processes. However, methanogenic archaea and/or particles may partially hinder combining MET and AD processes. Furthermore, it is unclear if the applied anode potential affects the activity and efficiency of electroactive microorganisms in AD-MET combinations as it is described for more controlled experimental conditions. In this study, we confirm that 6-week-old spp. dominated biofilms are by far more active and stable in AD-effluents than 3-week-old spp. dominated biofilms. Furthermore, we show that the biofilms are twice as active at -0.2 V compared to 0.4 V, even under challenging conditions occurring in AD-MET systems. Paired-end amplicon sequencing at the DNA level using 16S-rRNA and gene shows that hydrogenotrophic methanogens incorporate into biofilms immersed in AD-effluent without any negative effect on biofilm stability and electrochemical activity.
Topics: Bioelectric Energy Sources; Geobacter; Anaerobiosis; Biofilms; Electrodes
PubMed: 36731122
DOI: 10.1021/acs.est.2c07574