Culturomics of Anaerobic Sludge

Ever increasing concerns surrounding climate change are making alternative energy sources a focus of global discussion. Anaerobic digestion holds promise as one method of generating renewable energy with a low carbon footprint. The simple principle that underlies anaerobic digestion is the degradation of organic material by microorganisms to produce digestate and biogas. While this process occurs without human intervention in a variety of environments, there is still large scope for refinement of the process in order to increase its efficiency in industry. A key problem that limits technology advancement is the understanding of the microbiomes within anaerobic digesters. This can be attributed to the fastidious growth requirements of many of the organisms involved and as such, novel methods for culturing must be adopted if we are to advance our understanding. Work undertaken used a number of different growth backgrounds and isolation chips as a novel method for the enrichment of methanogens and anaerobic fungi from anaerobic sludge samples. 16S rRNA gene sequencing technology was used to assign taxonomy to 1,152 samples. A potential novel bacterial species was further investigated using fluorescent in-situ hybridisation and Sanger sequencing with a view to demonstrating the efficacy of this culturing method for the isolation and culturing of novel microbes. This alternative approach for the cultivation of multiple microbes in isolation has shown promise in terms of the number of novel species grown. Given that 16 samples were investigated at an individual level and one of these has been identified as a novel species, it is likely that novel species have also been cultured within the other 1,136 samples that have not yet been studied individually. This experiment provides a starting point from which a more streamlined method can be developed or altered to produce different microbial populations.