The invention relates to compositions and methods for the preparation, manufacture and therapeutic use of polynucleotides, primary transcripts and mmRNA molecules.

A microorganism produces guanidinoacetic acid (GAA) and has at least one gene coding for a protein having the function of a NADH-dependent dehydrogenase. A method for the fermentative production of GAA uses such microorganism. A method produces creatine through fermentative production. Industrial feed stocks are used as starting material in the fermentative process.

A microorganism is transformed to be capable of producing guanidinoacetic acid (GAA). A method can be used for the fermentative production of GAA using such microorganism. A corresponding method can also be used for the fermentative production of creatine.

A microorganism is transformed to be capable of producing guanidinoacetic acid (GAA) having an inactivated amino acid exporter. The microorganism is used in a method for the fermentative production of GAA. Moreover, creatine is produced by a method of fermentative production.