scholarly journals Monitoring of seven industrial anaerobic digesters supplied with biochar

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kerstin Heitkamp ◽  
Adriel Latorre-Pérez ◽  
Sven Nefigmann ◽  
Helena Gimeno-Valero ◽  
Cristina Vilanova ◽  
...  

Abstract Background Recent research articles indicate that direct interspecies electron transfer (DIET) is an alternative metabolic route for methanogenic archaea that improves microbial methane productivity. It has been shown that multiple conductive materials such as biochar can be supplemented to anaerobic digesters to increase the rate of DIET. However, the industrial applicability, as well as the impact of such supplements on taxonomic profiles, has not been sufficiently assessed to date. Results Seven industrial biogas plants were upgraded with a shock charge of 1.8 kg biochar per ton of reactor content and then 1.8 kg per ton were added to the substrate for one year. A joint analysis for all seven systems showed a decreasing trend for the concentration of acetic acid (p < 0.0001), propionic acid (p < 0.0001) and butyric acid (p = 0.0022), which was significant in all cases. Quantification of the cofactor F420 using fluorescence microscopy showed a reduction in methanogenic archaea by up to a power of ten. Methanogenic archaea could grow within the biochar, even if the number of cells was 4 times less than in the surrounding sludge. 16S-rRNA gene amplicon sequencing showed a higher microbial diversity in the biochar particles than in the sludge, as well as an accumulation of secondary fermenters and halotolerant bacteria. Taxonomic profiles indicate microbial electroactivity, and show the frequent occurrence of Methanoculleus, which has not been described in this context before. Conclusions Our results shed light on the interplay between biochar particles and microbial communities in anaerobic digesters. Both the microbial diversity and the absolute frequency of the microorganisms involved were significantly changed between sludge samples and biochar particles. This is particularly important against the background of microbial process monitoring. In addition, it could be shown that biochar is suitable for reducing the content of inhibitory, volatile acids on an industrial scale.

2021 ◽  
Author(s):  
Kerstin Heitkamp ◽  
Adriel Latorre-Pérez ◽  
Sven Nefigmann ◽  
Helena Gimeno-Valero ◽  
Cristina Vilanova ◽  
...  

Abstract Background: Recent research articles indicate that direct interspecies electron transfer (DIET) is an alternative metabolic route for methanogenic archaea that improves microbial methane productivity. It has been shown that multiple conductive materials such as biochar can be supplemented to anaerobic digesters to increase the rate of DIET. However, the industrial applicability, as well as the impact of such supplements on taxonomic profiles, has not been sufficiently assessed to date. Results: Seven industrial anaerobic digesters were supplemented with biochar for one year. A positive effect was observed for the spectrum of organic acids as the concentration of acetic, propionic, and butyric acid decreased significantly. Quantification of the cofactor F420 using fluorescence microscopy showed a reduction in methanogenic archaea. 16S-rRNA gene amplicon sequencing showed a higher microbial diversity within biochar particles as well as an accumulation of secondary fermenters and halotolerant bacteria. Taxonomic profiles indicate microbial electroactivity, and show the frequent occurrence of Methanoculleus , which has not been described in this context before. Conclusions: Our results shed light on the interplay between biochar particles and microbial communities in anaerobic digesters. Both the microbial diversity and the absolute frequency of the microorganisms involved were significantly changed between sludge samples and biochar particles. This is particularly important against the background of microbial process monitoring. In addition, it could be shown that biochar is suitable for reducing the content of inhibitory, volatile acids on an industrial scale.


2020 ◽  
Vol 178 ◽  
pp. 115815 ◽  
Author(s):  
Theo Y.C. Lam ◽  
Ran Mei ◽  
Zhuoying Wu ◽  
Patrick K.H. Lee ◽  
Wen-Tso Liu ◽  
...  

2019 ◽  
Vol 21 (1) ◽  
pp. 283 ◽  
Author(s):  
Ivan Kushkevych ◽  
Jiří Cejnar ◽  
Monika Vítězová ◽  
Tomáš Vítěz ◽  
Dani Dordević ◽  
...  

Background: In recent years, various substrates have been tested to increase the sustainable production of biomethane. The effect of these substrates on methanogenesis has been investigated mainly in small volume fermenters and were, for the most part, focused on studying the diversity of mesophilic microorganisms. However, studies of thermophilic communities in large scale operating mesophilic biogas plants do not yet exist. Methods: Microbiological, biochemical, biophysical methods, and statistical analysis were used to track thermophilic communities in mesophilic anaerobic digesters. Results: The diversity of the main thermophile genera in eight biogas plants located in the Czech Republic using different input substrates was investigated. In total, 19 thermophilic genera were detected after 16S rRNA gene sequencing. The highest percentage (40.8%) of thermophiles was found in the Modřice biogas plant where the input substrate was primary sludge and biological sludge (50/50, w/w %). The smallest percentage (1.87%) of thermophiles was found in the Čejč biogas plant with the input substrate being maize silage and liquid pig manure (80/20, w/w %). Conclusions: The composition of the anaerobic consortia in anaerobic digesters is an important factor for the biogas plant operator. The present study can help characterizing the impact of input feeds on the composition of microbial communities in these plants.


Author(s):  
Annemarie Siebert ◽  
Katharina Hofmann ◽  
Lena Staib ◽  
Etienne V. Doll ◽  
Siegfried Scherer ◽  
...  

Abstract The highly complex raw milk matrix challenges the sample preparation for amplicon-sequencing due to low bacterial counts and high amounts of eukaryotic DNA originating from the cow. In this study, we optimized the extraction of bacterial DNA from raw milk for microbiome analysis and evaluated the impact of cycle numbers in the library-PCR. The selective lysis of eukaryotic cells by proteinase K and digestion of released DNA before bacterial lysis resulted in a high reduction of mostly eukaryotic DNA and increased the proportion of bacterial DNA. Comparative microbiome analysis showed that a combined enzymatic and mechanical lysis procedure using the DNeasy® PowerFood® Microbial Kit with a modified protocol was best suitable to achieve high DNA quantities after library-PCR and broad coverage of detected bacterial biodiversity. Increasing cycle numbers during library-PCR systematically altered results for species and beta-diversity with a tendency to overrepresentation or underrepresentation of particular taxa. To limit PCR bias, high cycle numbers should thus be avoided. An optimized DNA extraction yielding sufficient bacterial DNA and enabling higher PCR efficiency is fundamental for successful library preparation. We suggest that a protocol using ethylenediaminetetraacetic acid (EDTA) to resolve casein micelles, selective lysis of somatic cells, extraction of bacterial DNA with a combination of mechanical and enzymatic lysis, and restriction of PCR cycles for analysis of raw milk microbiomes is optimal even for samples with low bacterial numbers. Key points • Sample preparation for high-throughput 16S rRNA gene sequencing of raw milk microbiota. • Reduction of eukaryotic DNA by enzymatic digestion. • Shift of detected microbiome caused by high cycle numbers in library-PCR.


Author(s):  
Yoshihiro Tomizawa ◽  
Shunya Kurokawa ◽  
Daiki Ishii ◽  
Katsuma Miyaho ◽  
Chiharu Ishii ◽  
...  

Abstract Background The antibacterial effects of psychotropics may be part of their pharmacological effects when treating depression. However, limited studies have focused on gut microbiota in relation to prescribed medication. Method We longitudinally investigated the relationship between patients’ prescribed medications and intestinal bacterial diversity in a naturalistic treatment course for patients with major depressive disorders and anxiety disorders. Patients were recruited and their stool was collected at 3 time points during their usual psychiatric treatments. Gut microbiota were analyzed using 16S rRNA gene sequencing. We examined the impact of psychotropics (i.e., antidepressants, anxiolytics, antipsychotics) on their gut microbial diversity and functions. Results We collected 246 stool samples from 40 patients. Despite no differences in microbial diversity between medication groups at the baseline, over the course of treatment, phylogenic diversity whole-tree diversity decreased in patients on antipsychotics compared with patients without (P = .027), and beta diversity followed this trend. Based on a fixed-effect model, antipsychotics predicted microbial diversity; the higher doses correlated with less diversity based on the Shannon index and phylogenic diversity whole tree (estimate = −0.00254, SE = 0.000595, P &lt; .0001; estimate = −0.02644, SE = 0.00833, P = .002, respectively). Conclusion Antipsychotics may play a role in decreasing the alpha diversity of the gut microbiome among patients with depression and anxiety, and our results indicate a relationship with medication dosage. Future studies are warranted and should consider patients’ types and doses of antipsychotics in order to further elucidate the mechanisms of gut-brain interactions in psychiatric disorders.


2007 ◽  
Vol 73 (14) ◽  
pp. 4609-4618 ◽  
Author(s):  
Samuel Ohene-Adjei ◽  
Ronald M. Teather ◽  
Michael Ivan ◽  
Robert J. Forster

ABSTRACT Association patterns between archaea and rumen protozoa were evaluated by analyzing archaeal 16S rRNA gene clone libraries from ovine rumen inoculated with different protozoa. Five protozoan inoculation treatments, fauna free (negative control), holotrich and cellulolytic protozoa, Isotricha and Dasytricha spp., Entodinium spp., and total fauna (type A) were tested. We used denaturing gradient gel electrophoresis, quantitative PCR, and phylogenetic analysis to evaluate the impact of the protozoan inoculants on the respective archaeal communities. Protozoan 18S ribosomal DNA clone libraries were also evaluated to monitor the protozoal population that was established by the inoculation. Phylogenetic analysis suggested that archaeal clones associated with the fauna-free, the Entodinium, and the type A inoculations clustered primarily with uncultured phylotypes. Polyplastron multivesiculatum was the predominant protozoan strain established by the holotrich and cellulolytic protozoan treatment, and this resulted predominantly in archaeal clones affiliated with uncultured and cultured methanogenic phylotypes (Methanosphaera stadtmanae, Methanobrevibacter ruminantium, and Methanobacterium bryantii). Furthermore, the Isotricha and Dasytricha inoculation treatment resulted primarily in archaeal clones affiliated with Methanobrevibacter smithii. This report provides the first assessment of the influence of protozoa on archaea within the rumen microbial community and provides evidence to suggest that different archaeal phylotypes associate with specific groups of protozoa. The observed patterns may be linked to the evolution of commensal and symbiotic relationships between archaea and protozoa in the ovine rumen environment. This report further underscores the prevalence and potential importance of a rather large group of uncultivated archaea in the ovine rumen, probably unrelated to known methanogens and undocumented in the bovine rumen.


2011 ◽  
Vol 77 (16) ◽  
pp. 5682-5687 ◽  
Author(s):  
Erin E. King ◽  
Rachel P. Smith ◽  
Benoit St-Pierre ◽  
André-Denis G. Wright

ABSTRACTIn the dairy cattle industry, Holstein and Jersey are the breeds most commonly used for production. They differ in performance by various traits, such as body size, milk production, and milk composition. With increased concerns about the impact of agriculture on climate change, potential differences in other traits, such as methane emission, also need to be characterized further. Since methane is produced in the rumen by methanogenic archaea, we investigated whether the population structure of methanogen communities would differ between Holsteins and Jerseys. Breed-specific rumen methanogen 16S rRNA gene clone libraries were constructed from pooled PCR products obtained from lactating Holstein and Jersey cows, generating 180 and 185 clones, respectively. The combined 365 sequences were assigned to 55 species-level operational taxonomic units (OTUs). Twenty OTUs, representing 85% of the combined library sequences, were common to both breeds, while 23 OTUs (36 sequences) were found only in the Holstein library and 12 OTUs (18 sequences) were found only in the Jersey library, highlighting increased diversity in the Holstein library. Other differences included the observation that sequences with species-like sequence identity toMethanobrevibacter milleraewere represented more highly in the Jersey breed, whileMethanosphaera-related sequences and novel uncultured methanogen clones were more frequent in the Holstein library. In contrast, OTU sequences with species-level sequence identity toMethanobrevibacter ruminantiumwere represented similarly in both libraries. Since the sampled animals were from a single herd consisting of two breeds which were fed the same diet and maintained under the same environmental conditions, the differences we observed may be due to differences in host breed genetics.


2021 ◽  
Vol 12 ◽  
Author(s):  
Charles S. Cockell ◽  
Bettina Schaefer ◽  
Cornelia Wuchter ◽  
Marco J. L. Coolen ◽  
Kliti Grice ◽  
...  

We report on the effect of the end-Cretaceous impact event on the present-day deep microbial biosphere at the impact site. IODP-ICDP Expedition 364 drilled into the peak ring of the Chicxulub crater, México, allowing us to investigate the microbial communities within this structure. Increased cell biomass was found in the impact suevite, which was deposited within the first few hours of the Cenozoic, demonstrating that the impact produced a new lithological horizon that caused a long-term improvement in deep subsurface colonization potential. In the biologically impoverished granitic rocks, we observed increased cell abundances at impact-induced geological interfaces, that can be attributed to the nutritionally diverse substrates and/or elevated fluid flow. 16S rRNA gene amplicon sequencing revealed taxonomically distinct microbial communities in each crater lithology. These observations show that the impact caused geological deformation that continues to shape the deep subsurface biosphere at Chicxulub in the present day.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Davide Porcellato ◽  
Roger Meisal ◽  
Alberto Bombelli ◽  
Judith A. Narvhus

AbstractThe importance of the microbiome for bovine udder health is not well explored and most of the knowledge originates from research on mastitis. Better understanding of the microbial diversity inside the healthy udder of lactating cows might help to reduce mastitis, use of antibiotics and improve animal welfare. In this study, we investigated the microbial diversity of over 400 quarter milk samples from 60 cows sampled from two farms and on two different occasions during the same lactation period. Microbiota analysis was performed using amplicon sequencing of the 16S rRNA gene and over 1000 isolates were identified using MALDI-TOF MS. We detected a high abundance of two bacterial families, Corynebacteriaceae and Staphylococcaceae, which accounted for almost 50% of the udder microbiota of healthy cows and were detected in all the cow udders and in more than 98% of quarter milk samples. A strong negative correlation between these bacterial families was detected indicating a possible competition. The overall composition of the udder microbiota was highly diverse and significantly different between cows and between quarter milk samples from the same cow. Furthermore, we introduced a novel definition of a dysbiotic quarter at individual cow level, by analyzing the milk microbiota, and a high frequency of dysbiotic quarter samples were detected distributed among the farms and the samples. These results emphasize the importance of deepening the studies of the bovine udder microbiome to elucidate its role in udder health.


2020 ◽  
Vol 66 (4) ◽  
pp. 263-273
Author(s):  
Julien Saavedra-Lavoie ◽  
Anne de la Porte ◽  
Sarah Piché-Choquette ◽  
Claude Guertin ◽  
Philippe Constant

Trace gas uptake by microorganisms controls the oxidative capacity of the troposphere, but little is known about how this important function is affected by changes in soil microbial diversity. This article bridges that knowledge gap by examining the response of the microbial community-level physiological profiles (CLPPs), carbon dioxide (CO2) production, and molecular hydrogen (H2) and carbon monoxide (CO) oxidation activities to manipulation of microbial diversity in soil microcosms. Microbial diversity was manipulated by mixing nonsterile and sterile soil with and without the addition of antibiotics. Nonsterile soil without antibiotics was used as a reference. Species composition changed significantly in soil microcosms as a result of dilution and antibiotic treatments, but there was no difference in species richness, according to PCR amplicon sequencing of the bacterial 16S rRNA gene. The CLPP was 15% higher in all dilution and antibiotic treatments than in reference microcosms, but the dilution treatment had no effect on CO2 production. Soil microcosms with dilution treatments had 58%–98% less H2 oxidation and 54%–99% lower CO oxidation, relative to reference microcosms, but did not differ among the antibiotic treatments. These results indicate that H2 and CO oxidation activities respond to compositional changes of microbial community in soil.


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