The role of phages in anaerobic digesters
Phages are viruses that infect and lyse bacteria and archaea for their replication. For marine systems, phages are known to be responsible for the lysis of up to 20% of the microbial biomass daily (Suttle, 2007). Since phages have been detected in biogas plants as well, phages could also have a potential impact on the taxonomic and functional composition of the microbial communities involved and, thus, biogas production.
In this project, we investigate the interaction between phages and microorganisms to understand the influence of phages on the microbial communities in biogas plants and, in general, oxygen-free (anaerobic) systems (Rossi et al., 2022). Therefore, we have set-up cultivation systems that allow to track the infection of the phages and changes of process parameters like the gas composition or pH value. To identify phage proteins by mass spectrometry (Tims TOF pro), we have established specific enrichment methods (Hellwig et al 2023, in preparation). In one approach, the phage proteins are chemically tagged using Bioorthogonal Noncanonical Amino Acid Tagging (BONCAT) and subsequently modified using so-called click chemistry to enhance detection signals (Hatzenpichler et al., 2014; Pasulka et al., 2018).
Figure 1: Different phages detected in a lab-scale biogas reactor using electron microscopy (Talos L120C transmission electron microscope (Thermo Fisher Scientific, Eindhoven, Netherlands), Katharina Willenbücher, Max Ruber Institute, Herrmann Weigmann-Str. 1, Kiel, Germany).
Reference list
Hatzenpichler, R. et al. (2014) ‘In situ visualization of newly synthesized proteins in environmental microbes using amino acid tagging and click chemistry’, Environmental Microbiology, 16(8), pp. 2568–2590. doi: 10.1111/1462-2920.12436
Pasulka, A.L. et al. (2018) ‘Interrogating marine virus-host interactions and elemental transfer with BONCAT and nanoSIMS-based methods’, Environmental Microbiology, 20(2), pp. 671–692. doi: 10.1111/1462-2920.13996
Rossi, A. et al. (2022) ‘Analysis of the anaerobic digestion metagenome under environmental stresses stimulating prophage induction’, Microbiome, 10(1). doi: 10.1186/s40168-022-01316-w
Suttle, C.A. (2007) ‘Marine viruses--major players in the global ecosystem’, Nature Reviews. Microbiology, 5(10), pp. 801–812. doi: 10.1038/nrmicro1750