ZYMOGENIC Bacillus sp REVEALED IN ALEKSINAC (SERBIA) OIL SHALE

The demineralisation experiments are aimed at preparing native sedimentary organic matter concentrates, consisting mainly of insoluble kerogen. Initial desilicification experiments of three Aleksinac (Serbia) oil shale samples were carried out with the help of Bacillus circulans J o r d a n. The process was followed by pH measurement and determination of the number of microorganisms. Demineralisation efficiency was evaluated based on the ratio of SiO(2), Al(2)O(3) and Fe(2)O(3) contents in the substrates before and after the experiments. Surprisingly, in all experiments much better desilicification was observed in control tests compared to inoculated substrates. Discovery of a zymogenic culture in all three oil shale samples explained the apparent anomaly. Based on physiological, biochemical and taxonomic characteristics, the isolated zymogenic culture was identified as Bacillus sp.