Evaluating indigenous diversity and its potential for microbial methane generation from thermogenic coal bed methane reservoir

Microbial enhanced coal bed methane process has emerged as cheaper, feasible and environment friendly approach for enhancing coal bed methane (CBM) generation worldwide. Despite the fact that India has tremendous potential for CBM, there are many challenges towards microbial translation of CBM. Therefore, to explore the possibility of microbial enhanced CBM generation from the deep thermogenic CBM reservoir, diversity of the microbial community was investigated using the 16S rRNA gene amplification methods. Additionally, a culture dependent analysis from the formation water of the reservoir was performed to access the ability of the indigenous microbes to produce methane from coal when enriched with suitable nutrient supplements. Culture independent data revealed the nature of communities i.e. bacterial and archaeal domain, majorly from thermophilic profile. The bacterial community was dominated by proteobacterial and Firmicutes taxa, while archaeal community was dominated by Euryarchaeota taxa (acetoclastic methanogens). The enrichment cultures derived from the formation water were able to produce methane (1002 µmol/g coal) at 45 °C. The 16S rRNA gene analysis depicted that the enriched microbial culture was dominated with anaerobic thermophilic fermentative bacteria of Clostridiales family and acetoclastic Methanosarcinales methanogens. The present study depicts the biogenic methane generation in the thermogenic-gas containing CBM reservoir could be enhanced by stimulating the indigenous microorganisms through providing suitable nutrient supplements. Present investigation is likewise the prime response to deliberate about the capability of thermogenic CBM reservoir (temperature > 40 °C) in India for biogenic methane generation through culture independent and culture dependent examination.