The bio-production of chemicals and fuels using “modified” microorganisms is becoming a practicable substitution to the unsustainable petrochemical-based processes. However, most of natural organisms cannot directly serve as chassis organism to produce desired compounds. Therefore, the platform microorganisms need to be adapted and genetically modified through retrofitting and optimization processes introduced in synthetic biology and metabolic engineering disciplines. In silico pathway design using retrobiosynthetis is an established approach for discovering promising biosynthetic pathways.