Table 2_Long-term anaerobic biodegradation of miocene lignite by indigenous microbial communities: insights into carbon and nitrogen cycling.xlsx

The natural microbial community of detritic lignite was stimulated for growth through the addition of trace elements, vitamins, and carbon-bearing compounds such as yeast extract, nutrient broth, methanol, and sodium acetate.

A visual indicator of microbial activity was observed as the color of the fermentation solutions changed over time: from colourless to light yellow (after 3 months), dark brown (after 6 months), and finally black (after 1 year). This progression suggests the dissolution of fulvic and humic acids. At the end of the cultivation, the total nitrogen and total inorganic nitrogen (TIN) contents in the solutions were significantly reduced whereas in incubations with sodium acetate, dissolved organic nitrogen (DON) content significantly increased compared to the initial levels.