Bioprocesses, which involve biocatalysts for the production of useful compounds, are expected to become a leading player in green chemistry. The first step in bioprocess development is screening for useful biological reactions in the immense number of microorganisms with infinite diversity and versatility. This review introduces some examples of bioprocess development that started from process design stemming from the discovery of unique metabolic processes, reactions, and enzymes in microbial nucleic acid and lipid metabolisms.