Marker microbiome clusters are determined by operational parameters and specific key taxa combinations in anaerobic digestion

Abstract

In this study, microbiomes of 36 full-scale anaerobic digesters originated from 22 different biogas plants were compared by terminal restriction fragment length polymorphism (TRFLP) analysis. Regarding the differences in microbial community composition, a weighting of the environmental parameters could be derived from higher to lower importance as follows: (i) temperature, (ii) TAN and NH concentrations and conductivity, and (iii) the chemical composition of the supplied feedstocks. Biotic interactions between specific bacterial and archaeal community arrangements were revealed, whereby members of the phyla Bacteroidetes and Cloacimonetes combined with the archaeal genus Methanothrix dominated the conversion of homogeneous feedstocks, such as waste water sludge or industrial waste. As most of the detected TRFs were only found in a certain number of anaerobic digestion plants, each plant develops its unique microbiome. The putative rare species, the specialists, are potentially hidden drivers of microbiome functioning as they provide necessary traits under, e.g., process-inconvenient conditions.

Effect of a Profound Feedstock Change on the Structure and Performance of Biogas Microbiomes

“…Calusinska et al [11] reported that the core microbiome contained several members from the phylum Bacteroidetes and Firmicutes, which is confirmed by several previous studies reporting high abundances of these two phyla in reactors producing biogas [41][42][43][44][45][46]. In accordance with previous studies, the TRF-related microorganisms seem to be able to exist under various environmental conditions as the six reactor systems differed in their TAN concentrations as well as in the degradability of the supplied feedstocks; hence, they might be putative generalists belonging to the biogas core microbiome [11,19].…”

“…The phylogenetic assignment of the recorded terminal restriction fragments (TRFs) was conducted with the sequence library produced in Klang et al [13,14]. Additionally, we used an in-house database, currently containing about 3000 16S rRNA gene sequences from various projects carried out at the Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB) during the last ten years [19]. Within these projects, the microbial community structure in laboratory-and full-scale biogas reactors was investigated.…”

“…The development of the microbial community depends on the available substrates. Different feedstocks with different chemical compositions and bioavailability lead to different microbial communities [11,[13][14][15][16][17][18][19]. Therefore, knowledge of the microbial reaction to different feedstock compositions is highly important in order to avoid process disturbances, and changes in the feedstock composition have to be performed with caution.…”

The anaerobic digestion microbiome: a collection of 1600 metagenome-assembled genomes shows high species diversity related to methane production

“…While in the rumen methanogenesis results in loss of energy and carbon to the atmosphere [6], in anaerobic digesters methane production and purity is maximized for exploiting the economic value of the process. Methane production has been directly linked to the composition of the AD microbiome [7–9], and it is also under the control of microbial metabolism, which is in turn thermodynamically dependent on environmental parameters of the reactor [10,11]. The intimate connection between these parameters offers unique opportunities to improve process efficiency, which can be obtained through microbial selection or manipulation [12,13].…”

The Future Agricultural Biogas Plant in Germany: A Vision

“…Intensive research has provided new insights into the digestion process microbiology during the last two decades, still knowledge on the biogas microbiome is rather limited. Most of the microbiome members and even more their functions and ecological roles in the biogas process are still unknown [32][33][34][35][36][37].…”