Microbial community composition and methanogens’ biodiversity during a temperature shift in a methane fermentation chamber

ABSTRACT

More information on the connection between anaerobic digestion (AD) parameters and composition of the microbial community involved in the AD process is required to gain a better understanding of how a bioreactor functions. The aim of this study was to analyse the composition of microbial communities and the dynamics of methanogens’ biodiversity changes during the shift from mesophilic (38°C) to thermophilic (55°C) conditions during biogas production. The total microbial composition was examined via the metagenomic approach based on 16S rRNA gene sequencing, whereas the methanogen communities were analysed using PCR–DGGE (Polymerase Chain Reaction–Denaturing Gradient Gel Electrophoresis) of mcrA. Even though the temperature is one of the crucial parameters affecting microorganisms involved in the AD process, the results presented here revealed that there were no statistically significant differences in bacterial community composition between the mesophilic and thermophilic phases of the process. The most abundant phyla were found to be Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes. However, the methanogens’ community genotypic structure as examined by the PCR–DGGE method changed under thermophilic conditions. The temperature had the strongest impact on the archaeal methanogens in the fermentation chamber directly after implementing the temperature shift. A relatively higher biogas yield and average content of CH₄ in the produced biogas were observed under thermophilic conditions.

GRAPHICAL ABSTRACT

KEYWORDS:

• Methanogens
• microbial community
• mcrA gene
• metagenomic analysis
• anaerobic digestion

Acknowledgements

The authors would like to thank the Regional Center for Water and Wastewater Management Co. in Tychy, Poland for allowing us to conduct measurement of the physicochemical parameters and for organising the sampling procedure at the Wastewater Treatment Plant in Tychy–Urbanowice, Poland. This paper does not contain any studies with human participants or animals performed by any of the authors.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Anna Banach http://orcid.org/0000-0003-3965-8718

Additional information

Funding

This work was supported by Faculty of Power and Environmental Engineering, Silesian University of Technology [grant number 08/080/BK_18/0054].