Lutein is a high-value tetraterpenoid carotenoid that
is widely
used in feed, cosmetics, food, and drugs. Microbial synthesis of lutein
is an important method for green and sustainable production, serving
as an alternative to plant extraction methods. However, an inadequate
precursor supply and low catalytic efficiency of key pathway enzymes
are the main reasons for the low efficacy of microbial synthesis of
lutein. In this study, some strategies, such as enhancing the MVA
pathway and localizing α-carotene synthase OluLCY within the
subcellular organelles in Yarrowia lipolytica, were adopted to enhance the synthesis of precursor α-carotene,
which resulted in a 10.50-fold increase in α-carotene titer,
reaching 38.50 mg/L. Subsequently, by improving hydroxylase activity
with truncated N-terminal transport peptide and locating hydroxylases
to subcellular organelles, the final strain L9 producing 75.25 mg/L
lutein was obtained. Eventually, a lutein titer of 675.40 mg/L (6.13
mg/g DCW) was achieved in a 5 L bioreactor by adding the antioxidant
2,6-ditert-butyl-4-methylphenol.
This study realizes de novo synthesis of lutein in Y. lipolytica for the first time and achieves the
highest lutein titer reported so far.