FUEL PROCESSING TECHNOLOGY, vol.33, no.1, pp.61-75, 1993 (SCI-Expanded)
The effects of temperature, agitation rate, inoculum size, initial pH and concentrations of glucose and ammonium sulfate of the fermentation medium on the specific growth rate of Sulfolobus solfataricus, a new sulfur utilizing and removing bacterium, was investigated. Growth experiments were designed and arranged in appropriate groups to elucidate the influence of each parameter. The optimum value for each parameter that favored the maximum specific growth rate was calculated from models established through linear or nonlinear regressions of the relevant data. Around these optima, biodesulfurization experiments were performed in glucose or glucose deficient medium with sterilized or unsterilized lignite. Of these, the run with unsterilized coal in glucose medium yielded the maximum removal of total, organic, pyritic and inorganic sulfur forms as 57.79%, 47.81%, 71.43% and 97.73%, respectively. The decrease in organic sulfur content was highly remarkable and has not been reported before with a reduction of more than 2% on a formula base.