A process of producing an organic compound and/or an intermediary compound as defined herein by feeding carbon dioxide to a culture of a cyanobacterial cell and subjecting the culture to light, wherein the cell is capable of expressing a nucleic acid molecule, wherein the expression of the nucleic acid molecule confer on the cell the ability to convert a glycolytic intermediate into the organic compound and/or into the intermediary compound and wherein the nucleic acid molecule is under the control of a regulatory system which responds to a change in the concentration of a nutrient in the culture.