Syntrophic microbial communities on straw as biofilm carrier increase the methane yield of a biowaste-digesting biogas reactor

AIMS Bioengineering. 2015;2(3):264-276 DOI 10.3934/bioeng.2015.3.264

 

Journal Homepage

Journal Title: AIMS Bioengineering

ISSN: 2375-1487 (Print); 2375-1495 (Online)

Publisher: AIMS Press

LCC Subject Category: Technology: Chemical technology: Chemical engineering | Technology: Chemical technology: Biotechnology | Medicine: Medicine (General): Medical technology

Country of publisher: United States

Language of fulltext: English

Full-text formats available: PDF

 

AUTHORS

Frank R. Bengelsdorf (Institute of Microbiology and Biotechnology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany)
Christina Gabris (Institute of Microbiology and Biotechnology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany)
Lisa Michel (Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany)
Manuel Zak
Marian Kazda (Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany)

EDITORIAL INFORMATION

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Time From Submission to Publication: 4 weeks

 

Abstract | Full Text

Biogas from biowaste can be an important source of renewable energy, but the fermentation process of low-structure waste is often unstable. The present study uses a full-scale biogas reactor to test the hypothesis that straw as an additional biofilm carrier will increase methane yield; and this effect is mirrored in a specific microbial community attached to the straw. Better reactor performance after addition of straw, at simultaneously higher organic loading rate and specific methane yield confirmed the hypothesis. The microbial communities on straw as a biofilm carrier and of the liquid reactor content were investigated using 16S rDNA amplicon sequencing by means of 454 pyrosequencing technology. The results revealed high diversity of the bacterial communities in the liquid reactor content as well as the biofilms on the straw. The most abundant archaea in all samples belonged to the genera <i>Methanoculleus</i> and <i>Methanosarcina.</i> Addition of straw resulted in a significantly different microbial community attached to the biofilm carrier. The bacterium <i>Candidatus</i> Cloacamonas acidaminovorans and methanogenic archaea of the genus <i>Methanoculleus </i>dominated the biofilm on straw. Syntrophic interactions between the hydrogenotrophic <i>Methanoculleus</i> sp. and members of the hydrogen-producing bacterial community within biofilms may explain the improved methane yield. Thus, straw addition can be used to improve and to stabilize the anaerobic process in substrates lacking biofilm-supporting structures.