Methane and carbon dioxide cumulative amounts data for: Algal amendment enhances biogenic methane production from coals of different thermal maturity

The addition of small amounts of algal biomass to stimulate methane
production in coal seams is a promising low carbon renewable coalbed
methane enhancement technique. However, little is known about how the
addition of algal biomass amendment affects methane production from coals
of different thermal maturity. Here, we show that biogenic methane can be
produced from five coals ranging in rank from lignite to low-volatile
bituminous using a coal-derived microbial consortium in batch microcosms
with and without algal amendment. The addition of 0.1 g/L algal biomass
resulted in maximum methane production rates up to 37 days earlier and
decreased the time required to reach maximum methane production by 17–19
days when compared to unamended, analogous microcosms. Cumulative methane
production and methane production rate were generally highest in low rank,
subbituminous coals, but no clear association between increasing vitrinite
reflectance and decreasing methane production could be determined.
Microbial community analysis revealed that archaeal populations were
correlated with methane production rate (p=0.01), vitrinite reflectance
(p=0.03), percent volatile matter (p=0.03), and fixed carbon (p=0.02), all
of which are related to coal rank and composition. Sequences indicative of
the acetoclastic methanogenic genus Methanosaeta dominated low rank coal
microcosms. Amended treatments that had increased methane production
relative to unamended analogs had high relative abundances of the
hydrogenotrophic methanogenic genus Methanobacterium and the bacterial
family Pseudomonadaceae. These results suggest that algal amendment may
shift coal-derived microbial communities towards coal-degrading bacteria
and CO2-reducing methanogens. These results have broad implications for
understanding subsurface carbon cycling in coal beds and the adoption of
low carbon renewable microbially enhanced coalbed methane techniques
across a diverse range of coal geology.