BIOTREATMENT OF COALS AND COAL-RELATED COMPOUNDS BY HYDROGEN-UTILIZING MICROORGANISMS

Desulfovibrio desulfuricans and Acidianus brierleyi were used to study hydrogenation of coal, pretreated coal, asphaltenes, and model compou nds [diphenyl methane (DPM) and fumarate] under anaerobic conditions. This study involved three primary aspects: (1) determination of net hy drogen-uptake, (2) identification of the biohydrogenated product of fu marate, and (3) testing the influence of hydrogen uptake/biohydrogenat ion of coal in terms of direct liquefaction yield. The net hydrogen up take values (from Warburg and GC assays) by the coals or the model com pounds (controls) were less than that of the biotreated samples. The g reatest hydrogen uptake (net, 1878 mumol g-1; coal control, 245; cell control, 127) occurred in untreated coal KCER No. 4677 in the presence of D. desulfuricans. The net hydrogen uptake by coals varied dependin g upon the coal type and the microorganism. Model compound DPM showed its highest hydrogen uptake rate when catalysed by D. desulfuricans (1 50 mumol g-1 h-1). D. desulfuricans also hydrogenated 36% of the fumar ate to succinate in the presence of hydrogen. Biotreated coal KCER No. 4677 (with 1878 mumol H-2 g-1) was subsequently subjected to direct l iquefaction. It showed a net increase in liquefaction yield of 5-4% as a result of the biotreament.