EVALUATION OF SULFATE-REDUCING BACTERIA FOR DESULFURIZING BITUMEN OR ITS FRACTIONS

Type cultures of sulfate-reducing bacteria (SRB), SRB obtained from oi lfield production facilities and a sulfate-reducing microbial communit y obtained from Athabasca oil sands (ANFI) were examined for their abi lity to desulfurize bitumen or its associated fractions. No significan t reduction of the sulfur content of dibenzothiophene (DBT) was observ ed for Desulfovibrio vulgaris or ANFI, even though these cultures conv ert maximally 1% of DBT into biphenyl (BP), as found previously. Furth ermore, no significant reduction was observed in total sulfur content of vacuum gas oil, deasphalted oil or bitumen with this method. Growth of Desulfovibrio vulgaris or ANFI in the presence of DBT, bitumen or its fractions in medium lacking methylviologen also did not lead to si gnificant reduction in their total sulfur contents, even though the AN FI community appeared able to utilize the real feeds as a potential ca rbon and energy source. (C) 1997 Elsevier Science Ltd.