Fig. 1
From: Metabolic engineering approaches for the biosynthesis of antibiotics
The timeline of antibiotic discoveries approved for clinical use. Representative antibiotic classes are shown; left side of circle indicates the year of discovery for the first chemical belonging to the class. Right side of circle shows the proceeded development way for clinical use. Relevant standards are provided in parentheses. The ‘Golden era’ of antibiotic discovery (from the 1950s to the 1960s) is highlighted in yellow lines. Antibiotics are categorized as follows: green, natural antibiotics; blue, semi-synthetic antibiotics; orange, synthetic antibiotics