Metagenomic and microscopic investigation of a coal degrading microbial consortium

Coal seam gas (CSG) is of increasing interest internationally due to its potential as a relatively clean bridging fuel for energy generation. CSG can originate from either thermogenic or biogenic methanogenesis. A growing awareness that biogenic processes may contribute significantly to CSG reserves worldwide has fuelled interest in the microbial communities performing this transformation. In this study a microbial consortium sourced from Australian coal seam formation water, capable of methanogenesis using coal as the sole carbon source has been examined. A combination of 16S rRNA amplicon surveys, metagenomic sequencing and scanning electron microscopy was performed on the community over a time-course of inoculation to maturation on fresh coal surfaces. This research has identified key microbial components of the community as it develops over time and used the latest informatics tools to match genetic functions, such as the three methanogenesis pathways, to these community members. Microscopic observation coupled with DNA sequencing experiments of inoculated coal surfaces over a time-course has provided the first insights into the distinct stages of the coal colonisation process, including the first observation of a biofilm attached community and the first reports of specific taxa including Geobacter spp. involved in the early colonisation of coal surfaces.