Print Email Facebook Twitter Stable acetate production in extreme-thermophilic (70ºC) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens Title Stable acetate production in extreme-thermophilic (70ºC) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens Author Zhang, F. Zhang, Y. Ding, J. Dai, K. Van Loosdrecht, M.C.M. Zeng, R.J. Faculty Applied Sciences Department BT/Biotechnology Date 2014-06-12 Abstract The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (706C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 ± 0.06, 1.0 ± 0.13 and 0.4 ± 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation. Subject environmental biotechnologyenvironmental science To reference this document use: http://resolver.tudelft.nl/uuid:b2dc0eb2-4ee1-4c9b-b5e3-8d87c6b71856 DOI https://doi.org/10.1038/srep05268 Publisher Nature Publishing Group ISSN 2045-2322 Source Scientific Reports, 4, 2014 Part of collection Institutional Repository Document type journal article Rights (c) 2014 The Author(s)Creative Commons BY Files PDF vanLoosdrecht_2014.pdf 1.04 MB Close viewer /islandora/object/uuid:b2dc0eb2-4ee1-4c9b-b5e3-8d87c6b71856/datastream/OBJ/view