0000000000464066
AUTHOR
Olaf Luschnig
Shedding light on biogas: a transparent reactor triggers the development of a biofilm dominated by Rhodopseudomonas faecalis that holds potential for improved biogas production
AbstractConventional anaerobic digesters intended for the production of biogas usually operate in complete darkness. Therefore, little is known about the effect of light on microbial communities operating in anaerobic digesters. In the present work, we have studied through 16S rRNA gene amplicon Nanopore sequencing and shotgun metagenomic sequencing the taxonomic and functional structure of the microbial community forming a biofilm on the inner wall of a lab-scale transparent anaerobic biodigester illuminated with natural sunlight. The biofilm was composed of microorganisms involved in the four metabolic processes needed for biogas production. The biofilm proved surprisingly rich in Rhodops…
Microbial communities involved in biogas production exhibit high resilience to heat shocks
We report here the impact of heat-shock treatments (55 and 70 °C) on the biogas production within the acidification stage of a two-stage reactor system for anaerobic digestion and biomethanation of grass. The microbiome proved both taxonomically and functionally very robust, since heat shocks caused minor community shifts compared to the controls, and biogas yield was not decreased. The strongest impact on the microbial profile was observed with a combination of heat shock and low pH. Since no transient reduction of microbial diversity occured after the shock, biogas keyplayers, but also potential pathogens, survived the treatment. All along the experiment, the heat-resistant bacterial prof…
MOESM7 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 7: Table S7. Number of reads and mean length of reads for bacteria from the methane stages.
MOESM8 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 8: Table S8. Number of reads and mean length of reads for archaea from the methane stages.
Complete Genome Sequence of a New Firmicutes Species Isolated from Anaerobic Biomass Hydrolysis
ABSTRACT A new Firmicutes isolate, strain HV4-6-A5C, was obtained from the hydrolysis stage of a mesophilic and anaerobic two-stage lab-scale leach-bed system for biomethanation of fresh grass. It is assumed that the bacterial isolate contributes to plant biomass degradation. Here, we report a draft annotated genome sequence of this organism.
Complete Genome Sequence of a New Clostridium sp. Isolated from Anaerobic Digestion and Biomethanation
Here, we present the genome sequence and annotation of the bacterial strain HV4-5-A1G, a potentially new Clostridium species. Based on its genomic data, this strain may act as a keystone microorganism in the hydrolysis of complex polymers, as well as in the different acidogenesis and acetogenesis steps during anaerobic digestion.
Liquid co-substrates repower sewage microbiomes
AbstractA range of parameters are known to shape the methanogenic communities of biogas-producing digesters and to strongly influence the amount of biogas produced. In this work, liquid and solid fractions of grass biomass were used separately for semicontinuous batch methanation using sewage sludge as seed sludge. During 6 months of incubation, the amount of input COD was increased gradually, and the underlying methanogenic microbiome was assessed by means of microscopy-based automated cell counting and full-length 16S rRNA high-throughput sequencing. In this sense, we prove for the first time the suitability of the ONT™MinION platform as a monitoring tool for anaerobic digestion systems. …
MOESM3 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 1: Figure S3. SDS-PAGE displaying the protein profiles.
Ammonia removal during leach-bed acidification leads to optimized organic acid production from chicken manure
This work demonstrates the suitability of nitrogen removal during anaerobic acidification in batch configuration for a more efficient pre-treatment of chicken manure prior to anaerobic digestion. High loading rates corresponding to a total nitrogen input between 6.3 and 9.5 g L−1 allowed successful suppression of methanogenic archaea. To eliminate nitrogen, NH3-stripping and MAP (magnesium ammonium phosphate hexahydrate) precipitation were compared. In spite of decreased cell quantities detected using qPCR, removal of nitrogen caused an increase in volatile fatty acid (VFA) formation from 13 to 19%. The highest nitrogen removal during acidification (up to 29%) was achieved with three consec…
Complete Genome Sequence of a New Ruminococcaceae Bacterium Isolated from Anaerobic Biomass Hydrolysis
ABSTRACT A new Ruminococcaceae bacterium, strain HV4-5-B5C, participating in the anaerobic digestion of grass, was isolated from a mesophilic two-stage laboratory-scale leach bed biogas system. The draft annotated genome sequence presented in this study and 16S rRNA gene sequence analysis indicated the affiliation of HV4-5-B5C with the family Ruminococcaceae outside recently described genera.
Shedding light on biogas: Phototrophic biofilms in anaerobic digesters hold potential for improved biogas production
Conventional anaerobic digesters intended for the production of biogas usually operate in complete darkness. Therefore, little is known about the effect of light on their microbial communities. In the present work, 16S rRNA gene amplicon Nanopore sequencing and shotgun metagenomic sequencing were used to study the taxonomic and functional structure of the microbial community forming a biofilm on the inner wall of a laboratory-scale transparent anaerobic biodigester illuminated with natural sunlight. The biofilm was composed of microorganisms involved in the four metabolic processes needed for biogas production, and it was surprisingly rich in Rhodopseudomonas faecalis, a versatile bacterium…
MOESM2 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 5: Table S2. Overview of reaction stages and reactor performance.
Potential pitfalls of FISH microscopy as assessment method for anaerobic digesters
AbstractIn the present work we investigated how the state of a biogas reactor impacts the enumeration of prokaryotic cells by fluorescencein situhybridisation (FISH). Therefore, the correlation between gas production and FISH hybridisation rates was analysed in different anaerobic digester sludges. High gasification activity coincided with high hybridisation rates. Low hybridisation rates were especially achieved with reactor samples subjected to long starvation periods showing low biogas production.Based on our findings we conclude that samples for FISH analysis should be fixed as soon as possible to prevent a loss of microbial activity resulting in lower FISH signals. Furthermore, the loc…
Eubacteria and archaea communities in seven mesophile anaerobic digester plants in Germany
Background Only a fraction of the microbial species used for anaerobic digestion in biogas production plants are methanogenic archaea. We have analyzed the taxonomic profiles of eubacteria and archaea, a set of chemical key parameters, and biogas production in samples from nine production plants in seven facilities in Thuringia, Germany, including co-digesters, leach-bed, and sewage sludge treatment plants. Reactors were sampled twice, at a 1-week interval, and three biological replicates were taken in each case. Results A complex taxonomic composition was found for both eubacteria and archaea, both of which strongly correlated with digester type. Plant-degrading Firmicutes as well as Bacte…
MOESM1 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 4: Table S1. Description of the used seed sludge.
MOESM6 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 6: Table S6. Number of sequences and mean length for bacteria from the acidification stages.
Complete genome sequence of a new Bacteroidaceae bacterium isolated from anaerobic biomass digestion
Here, we present the genome sequence and annotation of HV4-6-C5C, a bacterial strain isolated from a mesophilic two-stage laboratory-scale leach bed biogas reactor system. Strain HV4-6-C5C may represent a new genus of the family Bacteroidaceae and may have a key role in acidogenesis and acetogenesis steps during anaerobic biomass digestion.
From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Background Separating acidification and methanogenic steps in anaerobic digestion processes can help to optimize the process and contribute to producing valuable sub-products such as methane, hydrogen and organic acids. However, the full potential of this technology has not been fully explored yet. To assess the underlying fermentation process in more detail, a combination of high-throughput sequencing and proteomics on the acidification step of plant material (grass) at both mesophilic and thermophilic temperatures (37 and 55 °C, respectively) was applied for the first time. Results High-strength liquor from acidified grass biomass exhibited a low biodiversity, which differed greatly depen…
Producing high-strength liquor from mesophilic batch acidification of chicken manure.
This report describes the results from anaerobic batch acidification of chicken manure as a mono-substrate studied under mesophilic conditions. The manure was diluted with tap water to prevent methane formation during acidification and to improve mixing conditions by reducing fluid viscosity; no anaerobic digester sludge has been added as an inoculum. Highest acidification rates were measured at concentrations of 10 gVS L−1 and 20 gVS L−1; the pH value remained high (pH 6.9–7.9) throughout the test duration and unexpected fast methane formation was observed in every single batch. At substrate concentrations of 10 gVS L−1 there was a remarkable methane formation representing a value of 82% …
MOESM4 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 2: Table S4. Mascot results.
MOESM5 of From grass to gas: microbiome dynamics of grass biomass acidification under mesophilic and thermophilic temperatures
Additional file 3: Table S5. Differentially expressed proteins.