Abstract:An yeast strain YP-1 was isolated on selective media containing azo dye reactive brilliant red K-2BP, and identified as Issatchenkia orientalis. The strain YP-1 could effectively decolorize reactive brilliant red K-2BP within the concentration of 400mg/L. It gave a maximal decolorization of 99% for reactive brilliant red K-2BP of 100mg/L after incubation for 12h, under the optimal culture conditions: inoculation volume 10%(V/V), pH within the range from 3 to 9, concentration of (NH4)2SO4 30.02%, and concentration of glucose 30.2%. The strain YP-1 could absorb reactive brilliant red K-2BP and subsequently biodegrade it. The strain YP-1 could also decolorize another azo dye reactive black 5 of 200mg/L, up to the decolorization of 99.5%.