Profiling the metabolically active community from a production scale biogas plant by means of high throughput metatranscriptome sequencing

Computational Genomics, Center for Biotechnology-CeBiTec, Bielefeld University, Bielefeld, Germany.
Journal of Biotechnology (Impact Factor: 2.87). 02/2012; 158(4):248-58. DOI: 10.1016/j.jbiotec.2012.01.020
Source: PubMed


Structural composition and gene content of a biogas-producing microbial community from a production-scale biogas plant fed with renewable primary products was recently analyzed by means of a metagenome sequencing approach. To determine the transcriptionally active part of the same biogas community and to identify key transcripts for the biogas production process, the metatranscriptome of the microorganisms was sequenced for the first time. The metatranscriptome sequence dataset generated on the Genome Sequencer FLX platform is represented by 484,920 sequence reads. Taxonomic profiling of the active part of the community by classification of 16S ribosomal sequence tags revealed that members of the Euryarchaeota and Firmicutes account for the dominant phyla. Only smaller fractions of the 16S ribosomal sequence tags were assigned to the phyla Bacteroidetes, Actinobacteria and Synergistetes. Among the mRNA-derived sequence tags from the metatranscriptome dataset, transcripts encoding enzymes involved in substrate hydrolysis, acidogenesis, acetate formation and methanogenesis could be identified. Transcripts for enzymes functioning in methanogenesis are among the most abundant mRNA tags indicating that the corresponding pathway is very active in the methanogenic sub-community. As a frame of reference for evaluation of metatranscriptome sequence data, the 16S rDNA-based taxonomic profile of the community was analyzed by means of high-throughput 16S rDNA amplicon sequencing. Processing of the obtained amplicon reads resulted in 18,598 high-quality 16S rDNA sequences covering the V3-V4 hypervariable region of the 16S rRNA gene. Comparison of the taxonomic profiles deduced from 16S rDNA amplicon sequences and the metatranscriptome dataset indicates a high transcriptional activity of archaeal species. Overall, it was shown that the most abundant species dominating the community also contributed the majority of the transcripts. In the future, key transcripts for the biogas production process will provide valuable markers for evaluation of the performance of biogas-producing microbial communities with the objective to optimize the biotechnology of this process.

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Available from: Waleed Abu Al-Soud
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    • "Advances in high-throughput sequencing and bulk extraction of mRNA allow for RNA-based studies of organismal functioning in complex environments. Despite certain technological challenges, microbial metatranscriptomics has already helped elucidate microbial responses to oil spills and the resulting deep-sea hydrocarbon plumes, differences between anoxic and oxic paddy soils, and metabolic activity of methane-producing microbes, to name a few [31] [41] [47]. Similarly, metatranscriptomic approaches have been used to investigate the functional diversity of the eukaryotic microorganisms within the rumen of muskoxen [37] and in forest soils [6] [44]. "
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    • "In recent years, the taxonomic composition and gene content of biogas microbial communities has been studied by applying high-throughput metagenome sequencing (Hanreich et al., 2013; Krause et al., 2008; Rademacher et al., 2012; Schlüter et al., 2008; Zakrzewski et al., 2012; Sundberg et al., 2013; Wilkins et al., 2014). For instance, taxonomic profiling based on 16S rRNA gene sequencing frequently revealed that members of the class Clostridia dominate biogas reactor communities (Rademacher et al., 2012; Zakrzewski et al., 2012; Sundberg et al., 2013; St-Pierre and Wright, 2013). Most of the metagenome reads originating from clostridial species, functionally represent sequences assigned to the context 'carbohydrate degradation' (Schlüter et al., 2008; Rademacher et al., 2012; Jaenicke et al., 2011). "
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