Inclusion of Red Macroalgae (Asparagopsis taxiformis) in Dairy Cow Diets Modulates Feed Intake, Chewing Activity and Estimated Saliva Secretion

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Methane inhibition by Asparagopsis taxiformis with rumen fluid collected from ventral and central location – a pilot study

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Microbiota-directed fibre activates both targeted and secondary metabolic shifts in the distal gut

Beneficial modulation of the gut microbiome has high-impact implications not only in humans, but also in livestock that sustain our current societal needs. In this context, we have tailored an acetylated galactoglucomannan (AcGGM) fibre to match unique enzymatic capabilities of Roseburia and Faecalibacterium species, both renowned butyrate-producing gut commensals. Here, we test the accuracy of AcGGM within the complex endogenous gut microbiome of pigs, wherein we resolve 355 metagenome-assembled genomes together with quantitative metaproteomes. In AcGGM-fed pigs, both target populations differentially express AcGGM-specific polysaccharide utilization loci, including novel, mannan-specific esterases that are critical to its deconstruction. However, AcGGM-inclusion also manifests a “butterfly effect”, whereby numerous metabolic changes and interdependent cross-feeding pathways occur in neighboring non-mannanolytic populations that produce short-chain fatty acids. Our findings show how intricate structural features and acetylation patterns of dietary fibre can be customized to specific bacterial populations, with potential to create greater modulatory effects at large

Mikrobielle samfunn i biogass reaktorer og deres kobling til stabilitet og ytelse

The Anaerobic digestion (AD) of organic material gathers a great interest worldwide due to the global needs for waste recycling and renewable energy production. Biogas, the end product of an AD process, is a mixture of methane and carbon dioxide. Biogas can be used for heating, electricity or upgraded to pure methane for vehicle fuels. It could also serve as a part of the cycle in biorefineries. Although widely applied for energy production, an improved knowledge regarding the underlying microbial community is desired to ensure stable and efficient energy production. Therefore, the studies described in this thesis aimed to increase the knowledge base of microbial community in biogas reactors and relate this to stability and performance of the digestion process.Anaerob nedbrytning av organisk materiale har stor interesse verden over på grunn av det globale behovet for resirkulering av avfall og generering av fornybar energi. Biogass, som er sluttproduktet etter er anaerob nedbrytningsprosess, består av en blanding metan og karbondioksid. Biogassen kan brukes til varme, strøm eller oppgraderes til ren metan og brukes som biodrivstoff. Den kan også tjene som en del av syklusen i et bioraffineri. Selv om anaerob nedbrytning for energiproduksjon er en godt etablert prosess, er økt forståelse om det underliggende mikrobielle samfunnet ønskelig for å sikre stabil og effektiv energiproduksjon. Studiene som beskrives i denne avhandlingen tar derfor sikte på å øke kunnskapsbasen rundt mikrobielle samfunn i biogassreaktorer, og relatere dette til stabilitet og ytelse i nedbrytningsprosessen.Norges forskningsrå

Biogas production and structure of the microbial community in labscale biogas reactors - effect of cow manure and ensiled fish waste

Verden i dag står overfor store miljømessige utfordringer, som trolig bare vil bli større i fremtiden. Vi produserer mer, vi bruker mer og energietterspørselen øker i takt med avfallshaugen. Dermed har også interessen rundt alternative energikilder og avfallshåndteringer økt de senere årene, for å møte utfordringer og behov på en miljøvennlig måte. Søkelyset er blant annet rettet mot den energirike gassen metan (CH4), som dannes ved anaerob degradering av biomasse til biogass. I tillegg til å generere fornybar energi, gir denne prosessen en effektiv avfallsbehandling av organisk materiale. Dannelsen av metan fra organisk materiale er en kompleks prosess, utført av et mikrobielt samfunn bestående av ulike bakterier og arker i synergi med hverandre. I Norge er landbruk og fiskenæring er to viktige ressurser, og avfall fra disse industriene har et stort biogasspotensiale. Likevel har erfaringer vist at biogassanlegg ofte kan være ustabile og med et lavt energiutbytte. For å overkomme begrensninger knyttet til prosessen og for optimalisering av biogassproduksjonen, er mer kunnskap rundt den mikrobielle prosessen nødvendig. Hovedmålsettingen med dette arbeidet var derfor å studere sammensetning og utvikling av det mikrobielle samfunnet, og dannelse av biogass i reaktorer med varierte ratioer av storfegjødsel i kombinasjon med ensilert fiskeavfall. Biogassproduksjonen viste et avtakende metanutbytte med økende andel fiskeavfall. I tillegg til kvalitative og kvantitative analyser av biomassen og produsert biogass, ble ulike metoder benyttet for å kartlegge mikrobiologisk tilstedeværelse og suksesjon i batchreaktorene med storfegjødsel og fiskeensilasje. En dyp karakterisering med high-throughput Illumina sekvensering avdekket Firmicutes, Bacteroidetes og Proteobacteria som mest tilstedeværende bakteriefylum. Medlemmer av Methanobacteriales ble observert som dominerende innen metanogene arker, og indikerte dermed at det meste av konverteringen til metan skjedde via hydrogenotrof metanogenese. En blandet Sanger-sekvensering utført på de samme prøvene som Illumina sekvenseringen, avslørte en konvergent utvikling i henhold til substrat. I tillegg ble qPCR-basert kvantifisering gjennomført for karakterisering av det relative forholdet mellom andelen av de ulike metanogruppene Methanosarcinales og Methanomicrobiales. Fluorescence in situ hybridization (FISH) benyttet i et forsøk på å kvantifisere forholdet mellom arker og bakterier i bioreaktorene, men bakgrunnsstøy gjorde kvantifisering umulig. Karakteriseringen av den mikrobielle stukturen avdekket tilstedeværelsen av de mest sentrale metanproduserende arkene, og som denne oppgaven viser gav Illumina-sekvensering et godt innblikk i det mikrobielle samfunnet i en biogassreaktor

Microbial communities in biogas reactors and their link to stability and performance

The Anaerobic digestion (AD) of organic material gathers a great interest worldwide due to the global needs for waste recycling and renewable energy production. Biogas, the end product of an AD process, is a mixture of methane and carbon dioxide. Biogas can be used for heating, electricity or upgraded to pure methane for vehicle fuels. It could also serve as a part of the cycle in biorefineries. Although widely applied for energy production, an improved knowledge regarding the underlying microbial community is desired to ensure stable and efficient energy production. Therefore, the studies described in this thesis aimed to increase the knowledge base of microbial community in biogas reactors and relate this to stability and performance of the digestion process

Biogas production from food waste via co-digestion and digestion-effects on performance and microbial ecology

In this work, performance and microbial structure of a digestion (food waste-only) and a co-digestion process (mixture of cow manure and food waste) were studied at mesophilic (37°C) and thermophilic (55°C) temperatures. The highest methane yield (480mL/g VS) was observed in the mesophilic digester (MDi) fed with food waste alone. The mesophilic co-digestion of food waste and manure (McoDi) yielded 26% more methane than the sum of individual digestions of manure and food waste. The main volatile fatty acid (VFA) in the mesophilic systems was acetate, averaging 93 and 172mg/L for McoDi and MDi, respectively. Acetate (2150mg/L) and propionate (833mg/L) were the main VFAs in the thermophilic digester (TDi), while propionate (163mg/L) was the major VFA in the thermophilic co-digester (TcoDi). The dominant bacteria in MDi was Chlorofexi (54%), while Firmicutes was dominant in McoDi (60%). For the mesophilic reactors, the dominant archaea was Methanosaeta in MDi, while Methanobacterium and Methanosaeta had similar abundance in McoDi. In the thermophilic systems, the dominant bacteria were Thermotogae, Firmicutes and Synergistetes in both digesters, however, the relative abundance of these phyla were diferent. For archaea, the genus Methanothermobacter were entirely dominant in both TDi and TcoDi.publishedVersio

Rumen metaproteomics: Closer to linking rumen microbial function to animal productivity traits

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A first insight into the fecal microbiota of the high Arctic muskoxen (Ovibos moschatus)

The faecal microbiota of muskoxen (n=3) pasturing on Ryøya (69° 33′ N 18° 43′ E), Norway, in late September was characterized using high-throughput sequencing of partial 16S rRNA gene regions. A total of 16 209 high-quality sequence reads from bacterial domains and 19 462 from archaea were generated. Preliminary taxonomic classifications of 806 bacterial operational taxonomic units (OTUs) resulted in 53.7–59.3 % of the total sequences being without designations beyond the family level. Firmicutes (70.7–81.1 % of the total sequences) and Bacteroidetes (16.8–25.3 %) constituted the two major bacterial phyla, with uncharacterized members within the family Ruminococcaceae (28.9–40.9 %) as the major phylotype. Multiple-library comparisons between muskoxen and other ruminants indicated a higher similarity for muskoxen faeces and reindeer caecum (P>0.05) and some samples from cattle faeces. The archaeal sequences clustered into 37 OTUs, with dominating phylotypes affiliated to the methane-producing genus Methanobrevibacter (80–92 % of the total sequences). UniFrac analysis demonstrated heterogeneity between muskoxen archaeal libraries and those from reindeer and roe deer (P=1.0e-02, Bonferroni corrected), but not with foregut fermenters. The high proportion of cellulose-degrading Ruminococcus-affiliated bacteria agrees with the ingestion of a highly fibrous diet. Further experiments are required to elucidate the role played by these novel bacteria in the digestion of this fibrous Artic diet eaten by muskoxen