title: Incubation of innovative methanogenic communities to seed anaerobic digesters.
abstract: The methanogenic communities in alternative inocula and their potential to increase CH4production in mesophilic and psychrophilic dairy manure-based anaerobic digesters were examined. Quantitative-PCR and terminal restriction fragment length polymorphism (T-RFLP) profiles were used to determine archaeal and methanogenic community changes when three inocula (wetland sediment (WS), landfill leachate (LL), and mesophilic digestate (MD)) were incubated at 15, 25, and 35 °C for 91 and 196 days. After each incubation period, the inocula were used in biochemical methane potential (BMP) tests at the incubation temperatures. There was no significant correlation between inoculum mcrA gene copy numbers and CH4produced in BMP tests, suggesting that population size was not a distinguishing characteristic for predicting CH4production. Archaeal composition in LL and WS reactors generally converged with MD reactors after incubation at 25 and 35 °C for 196 days. These MD reactors had high relative abundance of TRF 302, likely Methanosaetaceae, and low acetic acid (0.62-1.61 mM). At 15 °C incubation, most reactors were associated with high acetic acid (1.61-133.6 mM) and dominated by TRF 199, likely Methanosarcinaceae. The LL reactor incubated at 25 °C for 91 days had higher relative abundance of TRF 199 and produced significantly higher CH4than WS and MD reactors in BMP test. In the future, it may be possible to create enrichment cultures that favor particular methanogens and use them as inoculum to benefit digesters at low mesophilic temperatures. Our data provides evidence that tailoring the archaeal community could benefit digesters operating under different conditions.
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Bldg., College Park, Maryland, MD, 20742, USA.
authors.forename: Freddy
authors.initials: F
authors.lastname: Witarsa
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Bldg., College Park, Maryland, MD, 20742, USA. slansing@umd.edu.
authors.forename: Stephanie
authors.identifier: http://orcid.org/0000-0001-9169-3823
authors.initials: S
authors.lastname: Lansing
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Bldg., College Park, Maryland, MD, 20742, USA.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Yarwood
authors.affiliation: Department of Environmental Science and Technology, University of Maryland, 1449 Animal Science/Ag Engineering Bldg., College Park, Maryland, MD, 20742, USA.
authors.forename: Martina
authors.initials: M
authors.lastname: Gonzalez Mateu
mesh_terms: D000693:Anaerobiosis; D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000378:metabolism*; D058448:Biota; D008372:Manure / Q000382:microbiology*; D008697:Methane / Q000378:metabolism*; D012150:Polymorphism, Restriction Fragment Length; D060888:Real-Time Polymerase Chain Reaction; D013696:Temperature; D013997:Time Factors
chemical_list: D008372:Manure; D008697:Methane
keywords: Biochemical methane potential (BMP); Inoculum; Landfill leachate; T-RFLP; Wetland; qPCR