title: Structures of microbial communities found in anaerobic batch runs that produce methane from propionic acid--Seeded from full-scale anaerobic digesters above a certain threshold.
abstract: The volatile fatty acid propionate inhibits anaerobic digestion during organic waste treatments. To examine potential microbial interactions that accelerate propionate oxidation, anaerobic digestion systems seeded with various types of anaerobic sludge were analyzed. Seed samples were collected from 10 different full-scale anaerobic reactors in South Korea. Propionate oxidation was estimated as the methane production rate per gram of propionate used per day. Two domestic sewage sludge showed the highest methane production rate values, 109.1 ± 4.2 and 74.5 ± 8.6 mL CH4/(g propionate ∙ d). A food waste recycling wastewater source exhibited the lowest methane production rate, 33.2 ± 2.6 mL CH4/(g propionate ∙ d). To investigate how the microbial community structure affected propionate oxidation, qualitative molecular analyses were carried out using denaturing gradient gel electrophoresis. Methanosaeta concilii, an aceticlastic methanogen, was detected in most batch runs. Smithella propionica, a unique propionate oxidizer and simultaneous producer of acetate, was found in domestic sewage sludge sources showing the highest methane production rate; in contrast, Desulfobulbus rhabdoformis, a sulfate reducer coupled with the consumption of acetate to be used as a precursor of methane, was observed in food waste recycling wastewater sludge source showing the lowest methane production rate. Thus, we propose that S. propionica, a syntrophic acetate producer using propionate, might cooperate with aceticlastic methanogens for high methane production during anaerobic digestion that included propionate.
authors.affiliation: Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea.
authors.forename: Woong
authors.initials: W
authors.lastname: Kim
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.
authors.forename: Seung Gu
authors.initials: SG
authors.lastname: Shin
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.
authors.forename: Gyuseong
authors.initials: G
authors.lastname: Han
authors.affiliation: Center for Water Resource Cycle Research, Korea Institute of Science and Technology, 39-1 Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791, Republic of Korea.
authors.forename: Kyungjin
authors.initials: K
authors.lastname: Cho
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea. Electronic address: shwang@postech.ac.kr.
authors.forename: Seokhwan
authors.initials: S
authors.lastname: Hwang
mesh_terms: D000693:Anaerobiosis / Q000502:physiology*; D019149:Bioreactors / Q000382:microbiology*; D008697:Methane / Q000032:analysis / Q000378:metabolism*; D059013:Microbial Consortia; D011422:Propionates / Q000378:metabolism*; D056910:Republic of Korea; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology
chemical_list: D008697:Methane; D011422:Propionates; D062065:Wastewater; C029658:propionic acid
keywords: Anaerobic digestion; Collaboration; Methane; Propionate; Smithella