title: Impact of different antibiotics on methane production using waste-activated sludge: mechanisms and microbial community dynamics.
abstract: Anaerobic digestion is an effective method for reducing the by-product of waste-activated sludge (WAS) from wastewater treatment plants and for producing bioenergy from WAS. However, only a limited number of studies have attempted to improve anaerobic digestion by targeting the microbial interactions in WAS. In this study, we examined whether different antibiotics positively, negatively, or neutrally influence methane fermentation by evaluating changes in the microbial community and functions in WAS. Addition of azithromycin promoted the microbial communities related to the acidogenic and acetogenic stages, and a high concentration of soluble proteins and a high activity of methanogens were detected. Chloramphenicol inhibited methane production but did not affect the bacteria that contribute to the hydrolysis, acidogenesis, and acetogenesis digestion stages. The addition of kanamycin, which exhibits the same methane productivity as a control (antibiotic-free WAS), did not affect all of the microbial communities during anaerobic digestion. This study demonstrates the simultaneous functions and interactions of diverse bacteria and methanogenic Archaea in different stages of the anaerobic digestion of WAS. The ratio of Caldilinea, Methanosarcina, and Clostridium may correspond closely to the trend of methane production in each antibiotic. The changes in microbial activities and function by antibiotics facilitate a better understanding of bioenergy production.
authors.affiliation: Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, 808-0196, Japan.
authors.forename: Nurul Asyifah
authors.initials: NA
authors.lastname: Mustapha
authors.affiliation: Department of Applied Molecular Microbiology and Biomass Chemistry, Faculty of Agriculture, Kyushu University, 6-10-1 Hakozaki Higashi-ku, Fukuoka, 812-8581, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sakai
authors.affiliation: Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, 808-0196, Japan.
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Shirai
authors.affiliation: Department of Biological Functions Engineering, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, 808-0196, Japan. toshi.maeda@life.kyutech.ac.jp.|Research Center for Advanced Eco-fitting Technology, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, 808-0196, Japan. toshi.maeda@life.kyutech.ac.jp.
authors.forename: Toshinari
authors.identifier: http://orcid.org/0000-0002-6219-9110
authors.initials: T
authors.lastname: Maeda
mesh_terms: D000693:Anaerobiosis; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001105:Archaea / Q000145:classification; D017963:Azithromycin / Q000378:metabolism; D001419:Bacteria / Q000145:classification* / Q000187:drug effects*; D058448:Biota / Q000187:drug effects*; D002701:Chloramphenicol / Q000378:metabolism; D007612:Kanamycin / Q000378:metabolism; D008697:Methane / Q000378:metabolism*; D012722:Sewage / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D012722:Sewage; D007612:Kanamycin; D002701:Chloramphenicol; D017963:Azithromycin; D008697:Methane
keywords: Anaerobic digestion; Antibiotics; Methane; Microbial activity; Microbial community; Next generation sequencer