Ammonia stress on a resilient mesophilic anaerobic inoculum: Methane production, microbial community, and putative metabolic pathways

Christopher H Buhlmann; Bede S Mickan; Sasha N Jenkins; Stephan Tait; Tharanga K A Kahandawala; Parisa A Bahri

doi:10.1016/j.biortech.2018.12.012

Ammonia stress on a resilient mesophilic anaerobic inoculum: Methane production, microbial community, and putative metabolic pathways

Bioresour Technol. 2019 Mar:275:70-77. doi: 10.1016/j.biortech.2018.12.012. Epub 2018 Dec 7.

Authors

Christopher H Buhlmann¹, Bede S Mickan², Sasha N Jenkins³, Stephan Tait⁴, Tharanga K A Kahandawala⁵, Parisa A Bahri⁶

Affiliations

¹ Murdoch University School of Engineering and Information Technology, Murdoch University, 90 South St, Murdoch, WA 6150, Australia. Electronic address: christopherheinz.buhlmann@murdoch.edu.au.
² UWA School of Agriculture and Environment (M079), The University of Western Australia, Perth, WA 6009, Australia; The UWA Institute of Agriculture (M082), The University of Western Australia, Perth, WA 6009, Australia; Richgro Garden Products, 203 Acourt Rd, Jandakot, WA 6164, Australia.
³ UWA School of Agriculture and Environment (M079), The University of Western Australia, Perth, WA 6009, Australia; The UWA Institute of Agriculture (M082), The University of Western Australia, Perth, WA 6009, Australia.
⁴ Centre for Agricultural Engineering, The University of Southern Queensland, Toowoomba, QLD 4350, Australia.
⁵ UWA School of Agriculture and Environment (M079), The University of Western Australia, Perth, WA 6009, Australia.
⁶ Murdoch University School of Engineering and Information Technology, Murdoch University, 90 South St, Murdoch, WA 6150, Australia.

PMID: 30579103
DOI: 10.1016/j.biortech.2018.12.012

Abstract

Short term inhibition tests, 16S rRNA tag sequencing and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt), were employed to visualise the effects of increasing total ammoniacal nitrogen (TAN) concentration (3400-10166 ppm TAN) on microbial community structure and metabolic pathways for acetate degradation. The rate of methane production on acetate was significantly reduced by TAN concentrations above 6133 ppm; however, methane continued to be produced, even at 10166 ppm TAN (0.026 ± 0.0003 gCOD.gVS^-1_inoculum.day^-1). Hydrogenotrophic methanogenesis with syntrophic acetate oxidation (SAO) was identified as the dominant pathway for methane production. A shift towards SAO pathways at higher TAN concentrations and a decrease in the number of 'gene hits' for key genes in specific methanogenesis pathways was observed. Overall, the results highlighted potential for inhibition activity testing to be used together with PICRUSt, to estimate changes in microbial metabolism and to better understand microbial resilience in industrial AD facilities.

Keywords: Anaerobic digestion; Inhibition; Metabolic pathways; Methanogenesis; PICRUSt.

MeSH terms

Acetic Acid / metabolism
Ammonia / metabolism*
Anaerobiosis
Metabolic Networks and Pathways*
Methane / biosynthesis*
Microbiota*
Oxidation-Reduction
Stress, Physiological

Substances

Ammonia
Methane
Acetic Acid