Isolation and identification of a carbazole degradation gene cluster from Sphingomonas sp.JS1

摘要

The carbazole degrading bacterium JS1 was isolated from carbazole polluted soil and identified as Sphingomonas sp. bacterium based on its 16S rDNA gene. The car gene cluster located in the genome of JS1 was isolated by PCR and its presence verified by Southern hybridization. Sequence analysis of the car gene cluster showed that the arrangement of elements in JS1 was different from that of Pseudomons sp. CA10 and Nocardioides aromaticivorans IC177, but car gene cluster and neighboring regions were nearly identical to that of Sphingomonas sp. KA1 and Sphingomonas sp.GTIN11. Each element of the car gene cluster was expressed in E. coli upon IPTG induction. The amount of CaBb protein expressed was higher than CarBa and the ratio of these two proteins was 1:1.5. CarC expression level was detected using anti-CarC antibody. The result showed that carbazole degrading proteins were induced by the substrate carbazole. The quantity of CarC at 0.5 mg/ml carbazole was five times more than that at 0.1 mg/ml.