Cloning and expression of naphthalene dioxygenase genes from Comamonas sp. MQ for indigoids production

► We cloned and expressed the NDO genes from Comamonas sp. MQ. ► Strain ND_IND possessed high transformation efficiency towards most indoles. ► The absorbance spectra and mass spectra of major products from indoles were detected. ► The optimal conditions for indigo production by strain ND_IND were determined. ► We investigated the effects of phenol, pyridine and quinoline on indigo production.