Methods and systems are provided for producing codeinone within an engineered non-plant cell. The method comprises, within the engineered non-plant cell, producing a thebaine product. The method also comprises, within the engineered non-plant cell, contacting the thebaine product with an enzyme having thebaine 6-O-demethylase activity, thereby producing a neopinone product. Additionally, the method comprises, within the engineered non-plant cell, contacting the neopinone product with a neopinone isomerase, thereby producing a codeinone product.