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Open AccessArticle

pH and Phosphate Induced Shifts in Carbon Flow and Microbial Community during Thermophilic Anaerobic Digestion

Department of Microbiology, Universität Innsbruck, 6020 Innsbruck, Austria
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Microorganisms 2020, 8(2), 286; https://doi.org/10.3390/microorganisms8020286
Received: 21 January 2020 / Revised: 14 February 2020 / Accepted: 17 February 2020 / Published: 20 February 2020
(This article belongs to the Special Issue Anaerobic Digestion)
pH is a central environmental factor influencing CH4 production from organic substrates, as every member of the complex microbial community has specific pH requirements. Here, we show how varying pH conditions (5.0–8.5, phosphate buffered) and the application of a phosphate buffer per se induce shifts in the microbial community composition and the carbon flow during nine weeks of thermophilic batch digestion. Beside monitoring the methane production as well as volatile fatty acid concentrations, amplicon sequencing of the 16S rRNA gene was conducted. The presence of 100 mM phosphate resulted in reduced CH4 production during the initial phase of the incubation, which was characterized by a shift in the dominant methanogenic genera from a mixed Methanosarcina and Methanoculleus to a pure Methanoculleus system. In buffered samples, acetate strongly accumulated in the beginning of the batch digestion and subsequently served as a substrate for methanogens. Methanogenesis was permanently inhibited at pH values ≤5.5, with the maximum CH4 production occurring at pH 7.5. Adaptations of the microbial community to the pH variations included shifts in the archaeal and bacterial composition, as less competitive organisms with a broad pH range were able to occupy metabolic niches at unfavorable pH conditions. View Full-Text
Keywords: pH; phosphate; microbial community; carbon flow; next-generation sequencing; biogas; buffer; volatile fatty acids pH; phosphate; microbial community; carbon flow; next-generation sequencing; biogas; buffer; volatile fatty acids
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MDPI and ACS Style

Lackner, N.; Wagner, A.O.; Markt, R.; Illmer, P. pH and Phosphate Induced Shifts in Carbon Flow and Microbial Community during Thermophilic Anaerobic Digestion. Microorganisms 2020, 8, 286. https://doi.org/10.3390/microorganisms8020286

AMA Style

Lackner N, Wagner AO, Markt R, Illmer P. pH and Phosphate Induced Shifts in Carbon Flow and Microbial Community during Thermophilic Anaerobic Digestion. Microorganisms. 2020; 8(2):286. https://doi.org/10.3390/microorganisms8020286

Chicago/Turabian Style

Lackner, Nina; Wagner, Andreas O.; Markt, Rudolf; Illmer, Paul. 2020. "pH and Phosphate Induced Shifts in Carbon Flow and Microbial Community during Thermophilic Anaerobic Digestion" Microorganisms 8, no. 2: 286. https://doi.org/10.3390/microorganisms8020286

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