title: Anaerobic digestion of nitrogen rich poultry manure: Impact of thermophilic biogas process on metal release and microbial resistances.
abstract: Poultry manure is a nitrogen rich fertilizer, which is usually recycled and spread on agricultural fields. Due to its high nutrient content, chicken manure is considered to be one of the most valuable animal wastes as organic fertilizer. However, when chicken litter is applied in its native form, concerns are raised as such fertilizers also include high amounts of antibiotic resistant pathogenic Bacteria and heavy metals. We studied the impact of an anaerobic thermophilic digestion process on poultry manure. Particularly, microbial antibiotic resistance profiles, mobile genetic elements promoting the resistance dissemination in the environment as well as the presence of heavy metals were focused in this study. The initiated heat treatment fostered a community shift from pathogenic to less pathogenic bacterial groups. Phenotypic and molecular studies demonstrated a clear reduction of multiple resistant pathogens and self-transmissible plasmids in the heat treated manure. That treatment also induced a higher release of metals and macroelements. Especially, Zn and Cu exceeded toxic thresholds. Although the concentrations of a few metals reached toxic levels after the anaerobic thermophilic treatment, the quality of poultry manure as organic fertilizer may raise significantly due to the elimination of antibiotic resistance genes (ARG) and self-transmissible plasmids.
authors.affiliation: Leibniz Institute for Agricultural Engineering and Bio-Economy Potsdam, Dept. Bioengineering, Max-Eyth-Allee 100, D-14469 Potsdam, Germany.
authors.forename: Reshma
authors.initials: R
authors.lastname: Anjum
authors.affiliation: Faculty of Life Sciences and Technology, Beuth University of Applied Sciences, Berlin, Germany; Division of Infectious Diseases, University Medical Centre Freiburg, Freiburg, Germany.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Grohmann
authors.affiliation: Leibniz Institute for Agricultural Engineering and Bio-Economy Potsdam, Dept. Bioengineering, Max-Eyth-Allee 100, D-14469 Potsdam, Germany. Electronic address: nkrakat@atb-potsdam.de.
authors.forename: Niclas
authors.initials: N
authors.lastname: Krakat
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism*; D001673:Biodegradation, Environmental; D056804:Biofuels / Q000032:analysis; D002645:Chickens; D004063:Digestion; D006358:Hot Temperature; D008372:Manure / Q000032:analysis* / Q000382:microbiology; D019216:Metals, Heavy / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D011200:Poultry
chemical_list: D056804:Biofuels; D008372:Manure; D019216:Metals, Heavy; D009584:Nitrogen
keywords: Anaerobic digestion; Antibiotic resistance genes; Conjugative plasmids; Metals; Poultry manure; Thermophilic temperature