The present disclosure relates to methods of treating at least one symptom of a mental disorder or disease of the central nervous system in a subject by modulating the amount of GABA produced in the subject's gut. The present disclosure also relates to methods of culturing the bacterial strain new bacterial strains. Also disclosed are methods of identifying bacterial strains capable of producing GABA, and engineering strains to produce GABA.

Provided herein, among other things, is an engineered non-plant cell that produces a tropane alkaloid product, a precursor of a tropane alkaloid product, or a derivative of a tropane alkaloid product. A method for producing a tropane alkaloid, a precursor of a tropane alkaloid product, or a derivative of a tropane alkaloid product that makes use of the cell is also described.

The present disclosure relates to methods of treating at least one symptom of a mental disorder or disease of the central nervous system in a subject by modulating the amount of GABA produced in the subject's gut. The present disclosure also relates to methods of culturing the bacterial strain new bacterial strains. Also disclosed are methods of identifying bacterial strains capable of producing GABA, and engineering strains to produce GABA.