Pseudomonas spp. are key players in agricultural biogas substrate degradation

Abstract

Anaerobic degradation (AD) of heterogeneous agricultural substrates is a complex process involving a diverse microbial community. While microbial community composition of a variety of biogas plants (BPs) is well described, little is known about metabolic processes and microbial interaction patterns. Here, we analyzed 16 large-scale BPs using metaproteomics. All metabolic steps of AD were observed in the metaproteome, and multivariate analyses indicated that they were shaped by temperature, pH, volatile fatty acid content and substrate types. Biogas plants could be subdivided into hydrogenotrophic, acetoclastic or a mixture of both methanogenic pathways based on their process parameters, taxonomic and functional metaproteome. Network analyses showed large differences in metabolic and microbial interaction patterns. Both, number of interactions and interaction partners were highly dependent on the prevalent methanogenic pathway for most species. Nevertheless, we observed a highly conserved metabolism of different abundant Pseudomonas spp . for all BPs indicating a key role during AD in carbohydrate hydrolysis irrespectively of variabilities in substrate input and process parameters. Thus, Pseudomonas spp . are of high importance for robust and versatile AD food webs, which highlight a large variety of downstream metabolic processes for their respective methanogenic pathways.

Microbiological Surveillance of Biogas Plants: Targeting Acetogenic Community

“…Peptococcaceae bacterium was also observed (RA ~3-8%) while the VFA levels were high in reactors C1-DD1. This OTU, also found in C3-K1/2 and in the stable phase in C5-A1/3, were 84-92% similar to Peptococcaceae bacterium 1109, previously proposed to be a syntrophic organic acid-oxidising bacterium (Town et al, 2014;Town and Dumonceaux, 2016;Buettner et al, 2019;Wirth et al, 2019;Singh et al, 2021a). The OTU could also be related to the recently discovered and uncultured syntrophic propionate oxidising bacteria Candidatus Syntrophopropionicum ammoniitolerans isolated from propionate oxidising enrichments (Singh et al, 2021b).…”

“…Further, the results from this study indicates that the applied method is able to target not only the potential acetogenic community but also syntrophic organic-acid oxidising bacterial communities viz. syntrophic acetate-oxidising bacteria (SAOB; phylum Cloacimonetes, Tepidanaerobacter, Peptococcaceae bacterium 1109; Sekiguchi et al, 2006;Westerholm et al, 2011b;Town et al, 2014;Town and Dumonceaux, 2016;Buettner et al, 2019;Wirth et al, 2019), syntrophic-propionate oxidising bacteria (phylum Cloacimonetes, family Peptococcaceae; Pelletier et al, 2008;Dyksma and Gallert, 2019;Singh et al, 2021b), syntrophic fatty-acid degraders (Syntrophomonas, Syntrophothermus; Sekiguchi et al, 2000;Zhang et al, 2004;Sousa et al, 2007) and syntrophic benzene degrading bacteria (family Peptococcaceae; van der Zaan et al, 2012;Gieg et al, 2014;Zhuang et al, 2015). Syntrophic organic-acid oxidising bacteria play a key role in the biogas process and even though not all being acetogens they can be detected due to the presence of FTHFS gene (Singh et al, 2019;Singh, 2021).…”

Profiling acetogenic community dynamics in anaerobic digesters - comparative analyses using next-generation sequencing and T-RFLP

“…The role of the genus Peptococcaceae bacterium or the family Peptococcaceae has not yet been well studied, but several studies suggest a role as an acetogen/syntrophic bacterium in natural and methanogenic environments (Müller et al 2010, 2016; Liu and Conrad 2011; Kato and Yumoto 2015; Tveit et al 2015; Liu et al 2016). Peptococcaceae bacterium 1109 is suggested to be a syntrophic acetate oxidising bacterium (Buettner et al 2019). Therefore the increased RA of this species during the VFA increase in the present study could potentially be associated with high levels of acetate in the disturbance phase, which are suggested to be of importance for other known syntrophic acetate-oxidising bacteria (Westerholm, Moestedt and Schnürer 2016).…”

A comparative analysis of biogas production from tomato bio-waste in mesophilic batch and continuous anaerobic digestion systems

“…One of the most common non-conventional energy carriers is biogas produced in anaerobic digestion (AD) processes. A wide variety of biomasses, such as maize or grass silage, crop plant and agricultural by-product, wastewater sludge, food processing by-products, domestic organic waste, and manure, have been used as substrates in biogas plants [1][2][3]. The stability and productivity of the biogas plants could be affected by diverse substrates.…”

“…The stability and productivity of the biogas plants could be affected by diverse substrates. Moreover, the microbial community composition fluctuates and varies with the substrates [ 1 ].…”