Structure and function of methanotrophic communities in a landfill-cover soil

In landfill-cover soils, aerobic methane-oxidizing bacteria (MOB) convert CH4 to CO2, mitigating emissions of the greenhouse gas CH4 to the atmosphere. We investigated overall MOB community structure and assessed spatial differences in MOB diversity, abundance and activity in a Swiss landfill-cover soil. Molecular cloning, terminal restriction-fragment length polymorphism (T-RFLP) and quantitative PCR of pmoA genes were applied to soil collected from 16 locations at three different depths to study MOB community structure, diversity and abundance; MOB activity was measured in the field using gas push-pull tests. The MOB community was highly diverse but dominated by Type Ia MOB, with novel pmoA sequences present. Type II MOB were detected mainly in deeper soil with lower nutrient and higher CH4 concentrations. Substantial differences in MOB community structure were observed between one high- and one low-activity location. MOB abundance was highly variable across the site [4.0 × 104 to 1.1 × 107 (g soil dry weight)-1]. Potential CH4 oxidation rates were high [1.8-58.2 mmol CH4 (L soil air)-1 day-1] but showed significant lateral variation and were positively correlated with mean CH4 concentrations (P < 0.01), MOB abundance (P < 0.05) and MOB diversity (weak correlation, P < 0.17). Our findings indicate that Methylosarcina and closely related MOB are key players and that MOB abundance and community structure are driving factors in CH4 oxidation at this landfil

No time to die : comparative study on preservation protocols for anaerobic fungi

Anaerobic fungi (AF, phylum Neocallimastigomycota) are best known for their ability to anaerobically degrade recalcitrant lignocellulosic biomass through mechanic and enzymatic means. While their biotechnological potential is well-recognized, applied research on AF is still hampered by the time-consuming and cost-intensive laboratory routines required to isolate, maintain, and preserve AF cultures. Reliable long-term preservation of specific AF strains would aid basic as well as applied research, but commonly used laboratory protocols for AF preservation can show erratic survival rates and usually exhibit only moderate resuscitation success for up to one or two years after preservation. To address both, the variability, and the preservation issues, we have set up a cross-laboratory, year-long study. We tested five different protocols for the preservation of AF. The experiments were performed at three different laboratories (Austria, Germany, Switzerland) with the same three morphologically distinct AF isolates (Anaeromyces mucronatus, Caeocmyces sp., and Neocallimastix cameroonii) living in stable co-culture with their naturally occurring, syntrophic methanogens. We could show that handling greatly contributes to the variability of results, especially in Anaeromyces mucronatus. Cryopreservation of (mature) biomass in liquid nitrogen had the highest overall survival rates (85–100%, depending on the strain and laboratory). Additionally, preservation on agar at 39°C had surprisingly high survival rates for up to 9 months, if pieces of agar containing mature AF thalli were resuscitated. This low-cost, low-effort method could replace consecutive batch cultivation for periods of up to 6 months, while long-term preservation is best done by cryopreservation in liquid nitrogen. Regardless of the method, however, preserving several replicates (>three) of the same strain is highly advisable

Towards a standardization of biomethane potential tests

Production of biogas from different organic materials is a most interesting source of renewable energy. The biomethane potential (BMP) of these materials has to be determined to get insight in design parameters for anaerobic digesters. Although several norms and guidelines for BMP tests exist, inter-laboratory tests regularly show high variability of BMPs for the same substrate. A workshop was held in June 2015, in Leysin, Switzerland, with over 40 attendees from 30 laboratories around the world, to agree on common solutions to the conundrum of inconsistent BMP test results. This paper presents the consensus of the intense roundtable discussions and cross-comparison of methodologies used in respective laboratories. Compulsory elements for the validation of BMP results were defined. They include the minimal number of replicates, the request to carry out blank and positive control assays, a criterion for the test duration, details on BMP calculation, and last but not least criteria for rejection of the BMP tests. Finally, recommendations on items that strongly influence the outcome of BMP tests such as inoculum characteristics, substrate preparation, test setup, and data analysis are presented to increase the probability of obtaining validated and reproducible results.info:eu-repo/semantics/publishedVersio

Biogene Güterflüsse in der Schweiz – Update 2014

2016 beauftragte das BAFU Bundesamt für Umwelt die Fachstelle Umweltbiotechnologie der ZHAW mit der Aktualisierung der Güterflussanalyse für biogene Güter in der Schweiz bezogen auf das Jahr 2014. Eine vergleichbare Studie wurde bereits in den Jahren 2011 (Datenbasis 2009) (Baum et al., 2012), 2008 (Datenbasis 2006) (Baum and Baier, 2008, 2009) und 2001 (Datenbasis 1998/9) (Scheurer and Baier, 2001) durchgeführt. Die vorliegende Studie «Biogene Güterflüsse der Schweiz – Update 2014» erfasst und visualisiert alle relevanten Güterflüsse biogener Güter der Schweiz anhand bestehender statistischer Erhebungen und Daten. Die vorliegende aktualisierte Version der Auflistung und Darstellung sämtlicher Flüsse biogener Güter der Schweiz stellt erneut eine Entscheidungsgrundlage dar, wenn es gilt, Konzepte zur stofflichen und energetischen Nutzung biogener Ressourcen zu planen und umzusetzen. Die gewählte Prozessstruktur hat sich als sinnvoll erwiesen, sie ist schnell erweiterbar und erlaubt, wie im vorliegenden Fall der Vergärung und Kompostierung, eine bedarfsorientierte Erweiterung des Detaillierungsgrades. Die regelmässige Aktualisierung der Güterflussanalyse biogener Güter der Schweiz erlaubt dabei auch die Darstellung von Veränderungen resp. die Beurteilung der Wirksamkeit von Massnahmen

Degradation of organic materials in an L/ILW repository

In a deep geological repository for low- and intermediate-level waste, organic substances are predominantly present in the waste itself, and to a smaller extent (< 5%) in conditioning materials and tunnel support. The degradation of organics will take place by a combination of abiotic and biotic processes. The abiotic ones (i.e., radiolysis and hydrolysis) reduce the molecular size of complex polymers before microorganisms can degrade them into even smaller compounds, down to thermodynamically stable CO2 and CH4. The latter are predicted to be the second-most important gases generated in the near-field of an L/ILW repository after H2. Quantitative assessments of CO2 and CH4 production rates during the degradation of organics are therefore required. Furthermore, the production of CO2 induces the carbonation of the cement-based engineered barriers, reducing their safety performance in terms of radionuclide sorption and highly alkaline buffer capacity (which in turn contributes to limiting gas generation by corrosion and/or microbial activities). A comprehensive literature review was conducted to better estimate gas generation rates from the degradation of organics, with a focus on the various abiotic and biotic processes to which the main organic materials present in the Swiss inventory for low- and intermediate-level waste (ion-exchange resins, PVC, bitumen, plastics, cellulose and Plexiglas®) are exposed. In the near-field of a cement-based low- and intermediate-level waste repository, organic materials are assumed to degrade mainly by hydrolysis and microbial processes, although the latter might be inhibited due to the highly alkaline conditions as well as limited water and nutrient availability. The radiolytic degradation of organics can, however, not be completely disregarded and mainly takes place shortly after closure of the low- and intermediate-level waste repository, when oxygen is still available, and the dose release (mostly from γ-emitters) is still high. In the temperature range expected in the near-field of a cement-based low- and intermediate- level waste repository over the period under consideration of 100,000 years (i.e., < 50 °C), thermal degradation might only enhance radiolysis and hydrolysis by a factor of ~ 2. The simplified classification of organic low- and intermediate-level waste into easily and less degradable organics (i.e., O1 and O2, respectively) was kept for the general licence application, as no individual rates could be attested for any of the organics inventoried in the low- and intermediate-level waste. The only change made in this classification concerns the two types of plastic polyesters and polycarbonates. These are now grouped together with easily degradable organics because they are susceptible to hydrolysis, which was not reflected in the Stage 2 rates of the Swiss Sectoral Plan for deep geological repositories. Moreover, the lower bounds of the gas generation rates for the general licence application were not set to zero anymore, as it can be now qualitatively assumed that the degradation of the organic low- and intermediate-level waste will occur, at least partly, over the period under consideration of 100,000 years. The lower bounds were fixed, based on the lowest rates measured and available in the literature. From the gas generation rates, the degradation rates of the organics can be estimated with a simplified kinetic model, which can further be used to assign an expected lifetime of the organic waste. A small portion of the organic materials present in L/ILW (e.g., superplasticisers, Plexiglas®, polyester, polycarbonates, cellulose and LMW organics) are expected to completely degrade during the period under consideration of 100,000 years. For the vast majority (e.g., ion-exchange resins, polystyrene, PVC and bitumen), complete degradation is hardly expected to occur as their lifetimes were estimated to be close to or even beyond the period of 100,000 years

Structure and function of methanotrophic communities in a landfill-cover soil

ISSN:0168-6496ISSN:1574-694

Effect of Growth Media on the Diversity of Neocallimastigomycetes from Non-Rumen Habitats

Joshi A, Young D, Huang L, et al. Effect of Growth Media on the Diversity of Neocallimastigomycetes from Non-Rumen Habitats. Microorganisms. 2022;10(10): 1972.Anaerobic fungi (AF), belonging to the phylum Neocallimastigomycota, are a pivotal component of the digestive tract microbiome of various herbivorous animals. In the last decade, the diversity of AF has rapidly expanded due to the exploration of numerous (novel) habitats. Studies aiming at understanding the role of AF require robust and reliable isolation and cultivation techniques, many of which remained unchanged for decades. Using amplicon sequencing, we compared three different media: medium with rumen fluid (RF), depleted rumen fluid (DRF), and no rumen fluid (NRF) to enrich the AF from the feces of yak, as a rumen control; and Przewalski’s horse, llama, guanaco, and elephant, as a non-rumen habitats. The results revealed the selective enrichment of Piromyces and Neocallimastix from the feces of elephant and llama, respectively, in the RF medium. Similarly, the enrichment culture in DRF medium explicitly manifested Piromyces-related sequences from elephant feces. Five new clades (MM1-5) were defined from llama, guanaco, yak, and elephant feces that could as well be enriched from llama and elephant samples using non-conventional DRF and NRF media. This study presents evidence for the selective enrichment of certain genera in medium with RF and DRF from rumen as well as from non-rumen samples. NRF medium is suggested for the isolation of AF from non-rumen environments

Presentation_1_No time to die: Comparative study on preservation protocols for anaerobic fungi.pdf

Anaerobic fungi (AF, phylum Neocallimastigomycota) are best known for their ability to anaerobically degrade recalcitrant lignocellulosic biomass through mechanic and enzymatic means. While their biotechnological potential is well-recognized, applied research on AF is still hampered by the time-consuming and cost-intensive laboratory routines required to isolate, maintain, and preserve AF cultures. Reliable long-term preservation of specific AF strains would aid basic as well as applied research, but commonly used laboratory protocols for AF preservation can show erratic survival rates and usually exhibit only moderate resuscitation success for up to one or two years after preservation. To address both, the variability, and the preservation issues, we have set up a cross-laboratory, year-long study. We tested five different protocols for the preservation of AF. The experiments were performed at three different laboratories (Austria, Germany, Switzerland) with the same three morphologically distinct AF isolates (Anaeromyces mucronatus, Caeocmyces sp., and Neocallimastix cameroonii) living in stable co-culture with their naturally occurring, syntrophic methanogens. We could show that handling greatly contributes to the variability of results, especially in Anaeromyces mucronatus. Cryopreservation of (mature) biomass in liquid nitrogen had the highest overall survival rates (85–100%, depending on the strain and laboratory). Additionally, preservation on agar at 39°C had surprisingly high survival rates for up to 9 months, if pieces of agar containing mature AF thalli were resuscitated. This low-cost, low-effort method could replace consecutive batch cultivation for periods of up to 6 months, while long-term preservation is best done by cryopreservation in liquid nitrogen. Regardless of the method, however, preserving several replicates (>three) of the same strain is highly advisable.</p