Arrested methanogenesis: Principles, practices, and perspectives

Tanvir, Rahamat Ullah; Ahmed, Muniruddin; Lim, Teng Teeh; Li, Yebo; Hu, Zhiqiang

doi:10.1016/bs.aibe.2022.04.001

Cited by 4 publications

(2 citation statements)

References 267 publications

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“…6 ). Similar to methanol, bacterial fermentation of polysaccharides into the VFAs butyrate and acetate also promotes the Methanobrevibater methanogenesis [ 43 ], via acetate assimilation through an incomplete reductive tricarboxylic acid cycle [ 41 ]. In this respect, Lachnospiraceae were the only taxonomic group showing a higher relative abundance of the transcripts involved in acetate production in cardoon biomass (Fig.…”

Section: Discussionmentioning

confidence: 99%

Structural and functional analysis of the active cow rumen’s microbial community provides a catalogue of genes and microbes participating in the deconstruction of cardoon biomass

Firrincieli,

Minuti,

Cappelletti

et al. 2024

Biotechnol Biofuels

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Background Ruminal microbial communities enriched on lignocellulosic biomass have shown considerable promise for the discovery of microorganisms and enzymes involved in digesting cell wall compounds, a key bottleneck in the development of second-generation biofuels and bioproducts, enabling a circular bioeconomy. Cardoon (Cynara cardunculus) is a promising inedible energy crop for current and future cellulosic biorefineries and the emerging bioenergy and bioproducts industries. The rumen microbiome can be considered an anaerobic “bioreactor”, where the resident microbiota carry out the depolymerization and hydrolysis of plant cell wall polysaccharides (PCWPs) through the catalytic action of fibrolytic enzymes. In this context, the rumen microbiota represents a potential source of microbes and fibrolytic enzymes suitable for biofuel production from feedstocks. In this study, metatranscriptomic and 16S rRNA sequencing were used to profile the microbiome and to investigate the genetic features within the microbial community adherent to the fiber fractions of the rumen content and to the residue of cardoon biomass incubated in the rumen of cannulated cows. Results The metatranscriptome of the cardoon and rumen fibre-adherent microbial communities were dissected in their functional and taxonomic components. From a functional point of view, transcripts involved in the methanogenesis from CO2 and H2, and from methanol were over-represented in the cardoon-adherent microbial community and were affiliated with the Methanobrevibacter and Methanosphaera of the Euryarchaeota phylum. Transcripts encoding glycoside hydrolases (GHs), carbohydrate-binding modules (CBMs), carbohydrate esterases (CEs), polysaccharide lyases (PLs), and glycoside transferases (GTs) accounted for 1.5% (6,957) of the total RNA coding transcripts and were taxonomically affiliated to major rumen fibrolytic microbes, such as Oscillospiraceae, Fibrobacteraceae, Neocallimastigaceae, Prevotellaceae, Lachnospiraceae, and Treponemataceae. The comparison of the expression profile between cardoon and rumen fiber-adherent microbial communities highlighted that specific fibrolytic enzymes were potentially responsible for the breakdown of cardoon PCWPs, which was driven by specific taxa, mainly Ruminococcus, Treponema, and Neocallimastigaceae. Conclusions Analysis of 16S rRNA and metatranscriptomic sequencing data revealed that the cow rumen microbiome harbors a repertoire of new enzymes capable of degrading PCWPs. Our results demonstrate the feasibility of using metatranscriptomics of enriched microbial RNA as a potential approach for accelerating the discovery of novel cellulolytic enzymes that could be harnessed for biotechnology. This research contributes a relevant perspective towards degrading cellulosic biomass and providing an economical route to the production of advanced biofuels and high-value bioproducts.

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Section: Discussionmentioning

confidence: 99%

Structural and functional analysis of the active cow rumen’s microbial community provides a catalogue of genes and microbes participating in the deconstruction of cardoon biomass

Firrincieli,

Minuti,

Cappelletti

et al. 2024

Biotechnol Biofuels

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“…The C/N ratio contributes to the efficiency of anaerobic digestion [32] by regulating microbial growth, by improving buffer capacity, and by providing process stability [33] (p. . The C/N ratio represents a very important factor in the production of a high level of biomethane, as this ratio indicates the degradation of organic matter by bacteria [34] (p. 135867), [35] (p. 621126).…”

Section: C/n Ratiomentioning

confidence: 99%

Influence upon Biogas Production of the C/N Ratio and the Heavy Metal Incidence in the Manure Composition

Halmaciu,

Ionel,

Miutescu

2024

Preprint

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The article presents comparative results from 5 categories of animals (4 samples originating from pigs, 2 from cows, 1 from chicken, 1 from ostriches, 1 from horses, samples quantified with A, B, C, D, E, F, G, H, I). These samples were collected from large, medium and small (family) farms. The results were validated by the biogas production generated by the respective samples, using the Automatic Methane Potential Test System (AMPTS II) bio-processor. The largest amounts of biogas (2,464.5 Nml, 2,262.0 Nml) were recorded for the samples from pig farms (Sample B and Sample D), whereas the lowest values were obtained in the case of Sample A (414.1 Nml) and Sample C (558.3 Nml). The heavy metals analyzed in the article are Zn, Cu, Fe, Mn, Ca, K, As. The results corroborate that the C/N ratio can also vary to values lower than 20-30, without affecting the biogas production process, and the heavy metal content must be known especially for the full management of the wastes. All final data presented in the article are based on repeated, triplicate experiments, with less as 2% deviation between data.

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Novel Specifications Regarding Biogas Production from Agriengineering Activities in Romania

Halmaciu,

Ionel,

Miutescu

et al. 2024

AgriEngineering

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This study centers on examining the carbon/nitrogen (C/N) ratio and metal levels in various batches of manure and their potential impact on biogas production through anaerobic fermentation. A novel aspect of this research involves the utilization of nine distinct batches sourced exclusively from livestock manure found in Romanian farms, without mixing with other potential substrates. At present, the farms are not harvesting manure for energy, but they are keen to invest in biogas production in the future as a necessary step towards renewable energy in a circular economy and a bio-waste management model. As a general conclusion that is resulting, it is shown that both the C/N ratio and the content of heavy metals in animal manure must be known when dealing with the animal manure fermentation process, especially when aiming for biogas production. The C/N ratio in the analyzed samples ranges from 6.7 to 30.2. While the ideal ratio is often considered 20–30, good methane production can occur outside this range, as seen in Sample B (small pig farm), with a C/N ratio of 13.8, proving the highest methane output. This shows that the C/N ratio is important but not the only factor influencing biogas generation. The metal content in the manure samples is similar to other studies, with potassium (K) ranging from 1.64% to 8.96%. Calcium (Ca) and K are the main metals found, posing little concern. The variation in values is linked to feed recipes. Monitoring heavy metals is crucial not only for biogas production but also for the safe use of animal manure as fertilizer, as soil contamination limits must be continuously supervised. The results are also valuable for the management of waste used as fertilizer in agricultural fields in accordance with EU law.

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Arrested methanogenesis: Principles, practices, and perspectives

Cited by 4 publications

References 267 publications

Structural and functional analysis of the active cow rumen’s microbial community provides a catalogue of genes and microbes participating in the deconstruction of cardoon biomass

Structural and functional analysis of the active cow rumen’s microbial community provides a catalogue of genes and microbes participating in the deconstruction of cardoon biomass

Influence upon Biogas Production of the C/N Ratio and the Heavy Metal Incidence in the Manure Composition

Novel Specifications Regarding Biogas Production from Agriengineering Activities in Romania

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