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摘要The biosynthesis of indigo has been attracting a huge attention for its increasing demand.In this study,a novel bacterial strain IDO capable of utilizing indole as sole carbon source was isolated from soil samples and identified as Cupriavidus sp.according to 16S rRNA sequence analysis.We found that Cupriavidus sp.strain IDO was able to degrade 100 mg/L indole in 12 h.High performance liquid chromatographymass spectrometry analysis indicated that indigo was the major products generated during indole biotransformation.The genomics,proteomics and functional studies were applied to investigate the genetic determinants for indigo biosynthesis in strain Cupriavidus sp.IDO.A total of 317 proteins were notably altered (262 up-and 55 downregulated) in the cells growing in indole mineral salt medium with respect to that in sodium citrate medium.After the related indole oxygenase genes were knocked out,strain IDO was unable to degrade indole and produce indigo.Furthermore,the indole oxygenase genes were cloned from strain IDO and successfully expressed in Escherichia coli BL21 (DE3) (designated as ING_IDO).Strain ING_IDO was able to produce 55 mg/L indigo from tryptophan medium.After optimization of induction time,IPTG concentration and culture medium,indigo production was increased to 110 mg/L.This study obtained valuable indole oxygenase and offered the promise of applying strain ING IDO for producing indigo.