Production of 3-Hydroxytyrosol from Glucose by Chromosomally Engineered Escherichia coli by Fed-Batch Cultivation in a Jar Fermenter

3-Hydroxytyrosol (HT) is a super antioxidant possessingmany physiologicaladvantages for human health. However, the extraction of natural HTfrom olive (Olea europaea) is expensive,and its chemical synthesis presents an environmental burden. Therefore,microbial production of HT from renewable sources has been investigatedover the past decade. In the present study, we modified the chromosomeof a phenylalanine-producing strain of Escherichiacoli to generate an HT-producing strain. The initialstrain showed good HT production in tests performed by test tube cultivation,but this performance did not transfer to jar-fermenter cultivation.To grow well and achieve higher titers, the chromosome was furtherengineered and the cultivation conditions were further modified. Thefinal strain achieved a higher HT titer (8.8 g/L) and yield (8.7%)from glucose in the defined synthetic medium. These yields are thebest reported to date for the biosynthesis of HT from glucose.