An engineered microbial cell that produces a benzylisoquinoline alkaloid product, said engineered microbial cell comprising a plurality of heterologous coding sequences for encoding a plurality of enzymes within a pathway for producing the benzylisoquinoline alkaloid product, wherein at least one heterologous coding sequence of the plurality of heterologous coding sequences encodes an enzyme that is within a pathway that converts a thebaine to the benzylisoquinoline alkaloid product, and wherein the benzylisoquinoline alkaloid product is selected from the group consisting of a neopinone, neopine, neomorphine, codeinone, codeine, morphine, oripavine, morphinone, hydrocodone, 14-hydroxycodeinone, dihydrocodeine, oxycodone, 14-hydroxycodeine, hydromorphone, and dihydromorphine.