title: Effect of organic loading on the microbiota in a temperature-phased anaerobic digestion (TPAD) system co-digesting dairy manure and waste whey.
abstract: Temperature-phased anaerobic digestion (TPAD) has gained increasing attention because it provides the flexibility to operate digesters under conditions that enhance overall digester performance. However, research on impact of organic overloading rate (OLR) to microbiota of TPAD systems was limited. In this study, we investigated the composition and successions of the microbiota in both the thermophilic and the mesophilic digesters of a laboratory-scale TPAD system co-digesting dairy manure and waste whey before and during organic overloading. The thermophilic and the mesophilic digesters were operated at 50 and 35 °C, respectively, with a hydraulic retention time (HRT) of 10 days for each digester. High OLR (dairy manure with 5 % total solid and waste whey of ≥60.4 g chemical oxygen demand (COD)/l/day) resulted in decrease in pH and in biogas production and accumulation of volatile fatty acids (VFAs) in the thermophilic digester, while the mesophilic digester remained unchanged except a transient increase in biogas production. Both denaturant gradient gel electrophoresis (DGGE) and Illumina sequencing of 16S ribosomal RNA (rRNA) gene amplicons showed dramatic change in microbiota composition and profound successions of both bacterial and methanogenic communities. During the overloading, Thermotogae was replaced by Proteobacteria, while Methanobrevibacter and archaeon classified as WCHD3-02 grew in predominance at the expense of Methanoculleus in the thermophilic digester, whereas Methanosarcina dominated the methanogenic community, while Methanobacterium and Methanobrevibacter became less predominant in the mesophilic digester. Canonical correspondence analysis (CCA) revealed that digester temperature and pH were the most influential environmental factors that explained much of the variations of the microbiota in this TPAD system when it was overloaded.
authors.affiliation: Environmental Science Graduate Program, The Ohio State University, Columbus, OH, USA.
authors.forename: Yueh-Fen
authors.initials: YF
authors.lastname: Li
authors.affiliation: Department of Animal Sciences, The Ohio State University, 2029 Fyffe Court, Columbus, OH, 43210, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Abraham
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Nelson
authors.affiliation: Department of Statistics, The Ohio State University, Columbus, OH, USA.
authors.forename: Po-Hsu
authors.initials: PH
authors.lastname: Chen
authors.affiliation: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, USA.
authors.forename: Joerg
authors.initials: J
authors.lastname: Graf
authors.affiliation: Environmental Science Graduate Program, The Ohio State University, Columbus, OH, USA. yu.226@osu.edu.|Department of Animal Sciences, The Ohio State University, 2029 Fyffe Court, Columbus, OH, 43210, USA. yu.226@osu.edu.
authors.forename: Zhongtang
authors.initials: Z
authors.lastname: Yu
mesh_terms: D000332:Aerobiosis; D001105:Archaea / Q000145:classification* / Q000235:genetics; D001419:Bacteria / Q000145:classification* / Q000235:genetics; D056804:Biofuels; D058448:Biota / Q000187:drug effects*; D001711:Biotransformation; D016000:Cluster Analysis; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D058645:Denaturing Gradient Gel Electrophoresis; D005232:Fatty Acids, Volatile / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D008372:Manure / Q000382:microbiology*; D009930:Organic Chemicals / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013696:Temperature; D000067796:Whey / Q000737:chemistry* / Q000382:microbiology*
chemical_list: D056804:Biofuels; D019641:DNA, Archaeal; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005232:Fatty Acids, Volatile; D007220:Industrial Waste; D008372:Manure; D009930:Organic Chemicals; D012336:RNA, Ribosomal, 16S
keywords: DGGE; Illumina sequencing; Microbiota; Organic overloading; TPAD