关键词: 乳白耙齿菌菌株CB1, ITS序列, 刚果红, 脱色

Abstract: [Objective] Strain Irpex lacteus CB1(Il-CB1)was identified firstly and its decoloring conditions to congo red was systematically studied so as to prove its application potentials in dye decolorization.[Method] On the basis of morphological identification, the ITS sequence of Il-CB1 was cloned and its phylogenetic analysis was made. The effects of pH value, congo red concentration, and adding time of dye on decoloring congo red by Il-CB1 were tested through single factor experiments, and the effects of other five factors including carbon concentration, nitrogen concentration, Cu²⁺ and Mn²⁺ concentration and inoculum volume on decolorization of Il-CB1 were studied through orthogonal experiment.[Result] The ITS sequence of Il-CB1 and other 24 ITS sequences from different I. lacteus strains clustered together, indicating that Il-CB1 was I. lacteus. The effect of pH value on congo red decolorization showed that decolorization percent increased first and then decreased with the increase of pH value. The decolorization percent both was very low under pH 3 and 8, the optimum pH value was 6.0. Decolorization percents under different congo red concentrations increased first and then decreased with the increase of congo red concentration. Decolorization percent under 100 mg·L^-1 congo red was the highest, and it decreased significantly under 250 mg·L^-1 congo red, indicating that lower congo red concentrations promoted decolorization, while higher congo red concentration inhibited decolorization. Orthogonal experiment showed that the most optimal culture parameters to decolorization were:glucose 10 g·L^-1, peptone 3 g·L^-1, Cu²⁺ and Mn²⁺ both 0.2 mmol·L^-1, 7 mL inoculum volume of mycelium liquor in 100 mL culture solution bottled in 250 mL flask. Decolorization percent was 99.60% on 5 d under above-mentioned conditions. Decolorization at different adding time of congo red was tested based on all above optimal culture conditions.The initial decolorization percent remained at a high level and it was up to 99.99% on 5 d when congo red was added 3 d after Il-CB1 was cultured.[Conclusion] Il-CB1 was identified as Irpex lacteus, it could degrade congo red effectively and might have extensively application potentials in degradation of dye wastewater.

Key words: Irpex lacteus CB1, ITS sequence, congo red, decolorization