Changes in organic matter of selected Miocene lignites and embedded sediments caused by microbial desulphurisation

► Changes in organic matter of lignites and gangue sediments due to microbial desulphurisation. ► More advanced changes in distribution of light-weight fraction of om bitumen. ► The influence of lithotype/maceral composition on the extent of alterations. ► Several biomarker and aromatic hydrocarbon parameters affected by microbial desulphurisation.