Biosynthesis of 2-phenylethanol from glucose with genetically engineered Kluyveromyces marxianus

• Metabolic engineering of K. marxianus for 2-phenylethanol production was attempted.
• Evolved strain producing high level of 2-PE was isolated.
• Bacterial aroGfbr was overexpressed in K. marxianus using an expression vector.
• 1.3 g/L of 2-PE was produced from glucose without addition of phenylalanine.

2-Phenylethanol (2-PE) is an aromatic alcohol with a rose scent, which is used in the cosmetics, fragrance and food industries. 2-PE is produced in a few yeast strains by Ehrlich pathway. In this study, Kluyveromyces marxianus was genetically engineered for overproduction of 2-PE from glucose. About 1.0 g/L of 2-PE was produced by overexpressing phenylpyruvate decarboxylase (ARO10) and alcohol dehydrogenase (ADH2) genes of Saccharomyces cerevisiae. A similar level of 2-PE was also produced from evolved K. marxianus, which was resistant to the phenylalanine analog, p-fluorophenylalanine. aroGfbr from Klebsiella pneumoniae encoding a feedback resistant mutant of 3-deoxy-D-arabino-heptulosonate-7-phosphate (DHAP) synthase was overexpressed in the evolved K. marxianus. Finally, 1.3 g/L of 2-PE was produced from 20 g/L glucose without addition of phenylalanine in the medium.