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PhD Defense by Rasmus Hansen Kirkegaard

Rasmus Hansen Kirkegaard, Department of Chemistry and Bioscience will defend his thesis on: "Identity and function of novel microbes in digesters"

Tidspunkt

28.02.2017 kl. 10.00 - 13.00

Beskrivelse

TITLE:

"Identity and function of novel microbes in digesters"

ABSTRACT:

Biogas production from wastewater streams represents a resource for replacing fossil fuels while minimising the cost and energy needs for waste treatment. This is a central part of the bio-refinery view of wastewater treatment plants and have the potential to turn them into small power plants as an alternative to costly treatment facilities. It is widely believed that we need to advance our understanding of the microbes to fully realise this potential and improve the performance of the underlying biological processes. To determine whether this is a feasible strategy, we need to grasp how many organisms we need to know. What organisms are present, are the same bacteria present in all reactors? Alternatively, do they differ between different reactors? Beyond identification, we also need to establish the functional roles of the different microbes within the digesters.

The aim of this project was to establish an overview of the microorganisms in Danish digesters treating primary and surplus sludge at wastewater treatment plant with a focus on novel microbes. In particular, the objectives were to identify novel and uncharacterised microorganisms important for the processes and obtain their genomic information to serve as a basis for future investigations.

We analysed the microbial community composition in 32 full-scale digesters using 16S rRNA gene amplicon sequencing. The reactors were sampled during a six-year period and we used influent samples to distinguish between microbes that were actively growing and the ones that were influent related. This analysis provided evidence for a short list of “most wanted” organisms that made up the majority of the biomass. To improve the discovery beyond PCR biased amplicon sequencing, we developed and tested methods for obtaining full-length SSU sequences directly from rRNA. This provided evidence for novel bacterial sequences within anaerobic digesters even from a single sample and holds the potential to expand the reference databases dramatically. Based on the survey we identified targets for genome recovery and developed the “mmgenome” tool to support reproducible genome binning. Using this tool, we successfully retrieved the first genomic information for members of the Hyd24-12 phylum (now Fermentibacteria), as well as a novel genus within the family Anaerolineaceae. 

SUPERVISOR:

  • Professor Per Halkjær Nielsen, Department of Chemistry and Bioscience

ASSESSMENT COMMITTEE:

  • Associate Professor, Lars Haastrup Pedersen  (Chairman), Department of Chemistry and Bioscience, AAU, Denmark
  • Professor, Anna Schnürer, Department of Microbiology, BioCenter, Sweden
  • Associate Professor, Dr. David Berry, Department of Microbiology and Ecosystem Science, Austria

AFTER THE DEFENSE A SMALL RECEPTION WILL BE HELD AT FREDRIK BAJERS VEJ 7H. 

Pris

Free

Arrangør

Department of Chemistry and Bioscience, AAU, Section of Biotechnology

Adresse

Fredrik Bajers Vej 7H, 9220 Aalborg Ø, room number: 1.102-6

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