title: A long-term study on the effect of magnetite supplementation in continuous anaerobic digestion of dairy effluent - Enhancement in process performance and stability.
abstract: Interspecies electron transfer (IET) between microbial populations with different functions is critical to stable anaerobic digestion. This study, in an attempt to facilitate IET, investigated the effect of magnetite supplementation on the biomethanation of dairy effluent in continuous mode. The magnetite-added reactor (RM) was significantly more resistant and resilient to process imbalance than the reactor run without magnetite addition (RC). RC showed unstable performance with repeated process upsets, but its performance improved to be comparable to that of RM after applying magnetite supplementation. Magnetite was particularly effective in stabilizing a build-up of propionic acid and therefore improving the process robustness and reliability. The enhanced biomethanation in terms of productivity and stability was attributed to the facilitated direct IET (DIET) between exoelectrogens and methanogens via magnetite particles. Methanosaeta was the predominant methanogen group in the experimental reactors and likely played a key role in both DIET-mediated carbon dioxide-reducing and aceticlastic methanogenesis.
authors.affiliation: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
authors.forename: Gahyun
authors.initials: G
authors.lastname: Baek
authors.affiliation: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea.
authors.forename: Jaai
authors.initials: J
authors.lastname: Kim
authors.affiliation: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Eonyang-eup, Ulju-gun, Ulsan 44919, Republic of Korea. Electronic address: cslee@unist.ac.kr.
authors.forename: Changsoo
authors.initials: C
authors.lastname: Lee
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology; D003612:Dairying; D052203:Ferrosoferric Oxide; D008697:Methane / Q000096:biosynthesis; D059013:Microbial Consortia / Q000502:physiology*; D010802:Phylogeny; D011422:Propionates / Q000378:metabolism; D015203:Reproducibility of Results; D014865:Waste Disposal, Fluid / Q000295:instrumentation / Q000379:methods*
chemical_list: D011422:Propionates; C029658:propionic acid; D008697:Methane; D052203:Ferrosoferric Oxide
keywords: Biomethanation; Biostimulation; Direct interspecies electron transfer; Magnetite; Microbial community structure