Bacteria engineered to treat a disease or disorder

A method of producing a pharmaceutically acceptable composition comprising a genetically-engineered non-pathogenic bacterium for use in metabolizing phenylalanine, the bacterium comprising

• at least one heterologous gene encoding a phenylalanine transporter for importing phenylalanine into the bacterium operably linked to a directly or indirectly inducible promoter that is not associated with the phenylalanine transporter in nature, and
• at least one heterologous gene encoding a polypeptide involved in metabolizing phenylalanine operably linked to a directly or indirectly inducible promoter that is not associated with the at least one heterologous gene encoding the polypeptide in nature,
• the method comprising the steps of:
• a) growing the bacterium in a growth medium culture under conditions that do not induce the promoter that controls expression of the transporter for importing phenylalanine;
• b) isolating the resulting bacteria from the growth medium;
• and
• c) suspending the isolated bacteria in a pharmaceutically acceptable carrier.