organism: environmental samples
description: In this study, two mesophilic (38 °C) and two thermophilic (50 °C) laboratory-scale fermenters (44 l working volume) fed with maize silage only were investigated in the course of different community compositions during different process stages. The two reactors for each temperature were operated in parallel. The start-up of all fermenters was performed using inoculation material from an industrial scale biogas plant located in Eschelbach an der Ilm, Germany, consisting of 72% maize silage, 21% whole-crop silage from rye, 3% chicken manure and small amounts of cow dung, corn cob mix and grass silage. The inoculum was taken from the secondary reactor (operated at 44 °C) or the main fermenter (operated at 46 °C) for mesophilic or thermophilic fermenter operation, respectively. Additionally, the thermophilic inoculum was diluted with digestate from a lab-scale reactor (80% maize silage, 20% grass silage operated at 38 °C) and tap water resulting in a ratio of 56:25:19. After stable process conditions were reached, the organic loading rate (OLR) of the reactors was increased incrementally to stimulate the stable process to an acidified (mesophilic) or highly efficient (thermophilic) process condition. The process was defined as stable when no accumulation of volatile fatty acids (VFAs) was observed, and the methane yield was in an expected range between 350 – 400 LSTP CH4 * kgVS-1. After increasing the OLR, VFAs accumulated in both mesophilic reactors, and the methane yield dropped below 300 LSTP CH4 * kgVS-1. This process was defined as acidified. The OLR of the thermophilic reactors was also increased, but VFAs did not accumulate, and the methane yield was recorded in an expected range between 350 – 400 LSTP CH4 * kgVS-1. Therefore, the process was defined as highly efficient. The mesophilic reactors, stable (m_st) or acidified (m_ac), were operated at an OLR of 2.5 kgVS * m-3 * d-1 or 1.0 kgVS * m-3 * d-1, respectively. The thermophilic reactors, stable (t_st) or highly efficient (t_ef), were operated at an OLR of 2.0 kgVS * m-3 * d-1 or 4.0 kgVS * m-3 * d-1, respectively. Both, RNA and DNA were extracted, DNA-free RNA was reverse transcribed into cDNA, and both aplified by PCR using the universal gene specific 16S bacterial primers F939 (5'->3' forward primer GAATTGACGGGGGCCCGCACAAG) and R1378 (5'->3' reverse primer CGGTGTGTACAAGGCCCGGGAACG) targeting the hypervariable region V6-V8 of the 16S rRNA gene. Liebraries were sequenced via paired-end sequencing by synthesis on an Illumina MiSeq system with a sequencing length of 2x300 bp PE, following manufacturer's instructions.
attributes.tag: collection date
attributes.value: 2018-08-06
attributes.tag: comment
attributes.value: MOD18
attributes.tag: dna/cdna
attributes.value: cDNA
attributes.tag: environment (biome)
attributes.value: anaerobic digester
attributes.tag: environment (feature)
attributes.value: laboratory scale biogas bioreactor
attributes.tag: environment (material)
attributes.value: nucleic acid extract
attributes.tag: geographic location (country and/or sea)
attributes.value: Germany
attributes.tag: geographic location (latitude)
attributes.value: 48.399836 N
attributes.tag: geographic location (longitude)
attributes.value: 11.728651 E
attributes.tag: investigation type
attributes.value: bacteria_archaea
attributes.tag: miscellaneous environmental package
attributes.value: miscellaneous natural or artificial environment
attributes.tag: project name
attributes.value: PRJEB37872
attributes.tag: sequencing method
attributes.value: MiSeq
attributes.tag: tank
attributes.value: T2
attributes.tag: variant
attributes.value: Versuchsende
attributes.tag: ENA-FIRST-PUBLIC
attributes.value: 2020-05-15
attributes.tag: ENA-LAST-UPDATE
attributes.value: 2020-05-15