Abstract: Growth behavior and desulfurization ratio of Rhodococcus Erythropolis NCC-1 with the presence of direct currents(DC) were studied.The electric field-activated mechanism was also investigated.The results show that direct current can improve the desulfurization ratio of NCC-1 within an appropriate scope of current density.The optimized current density is 0.72 A/m².Using 0.2 mmol/L dibenzothiophene (DBT) as a probe,the complete removal time of DBT by NCC-1 could be shortened on platinum electrodes,e.g.24 h less than that without the presence of direct electric fieldor 48 h less than that using titanium electrodes under a current density of 0.72 A/m².The desulfurization ratio can reach 67.4% at platinum electrodes under optimized direct current density in a mixture of water to diesel fuel with a ratio of 1:9.This value is 11.7% and 24.6% higher than those achieved on titanium electrode and in a system without the presence of direct electric field,respectively.This could be ascribed to the different ratio of adsorbed hydrogen to released H₂ produced from water on the cathode.The released H₂ could significantly promote the shaking culture of the bacterium.