Oil biodesulphurization is an important step in combating pollution problems emanating from burning fossil fuels. Rhizopus nigricans was used as the biological agent during the biodesulphurization process. The organism was cultured in a broth medium containing 1.5% glucose, 0.05% yeast extract, 0.5g/litre KCl, 2g/litre NH 4 NO 3 , 1.5g/litre KH 2 PO 4 and 1g/litre sodium metabisulphite (Na 2 S 2 O 5). R. nigricans was continuously cultured in this medium composition but with increasing concentrations of Na 2 S 2 O 5 . The organism could not grow beyond 15g/litre concentration of Na 2 S 2 O 5 . The organism was harvested and immobilized using the alginate entrapment method. The oil samples were digested and analyzed for sulphur. The analysis showed that when 50g of the immobilized spores of R. nigricans were used to treat 100ml of the oil samples, not less than 90.5% sulphur were metabolized. 92.18% and 90.9% sulphur were also metabolized at an optimum temperature of 35 o C and 168 hours respectively