Abstract
Sterols are essential lipid components for the cell membrane. In addition to
their structural roles, they are critical signaling molecules that regulate metabolism,
development, and homeostasis. Due to the functions of sterols being concentrationdependent, the biosynthesis of sterols is tightly controlled. Here, we reviewed the
biosynthesis processes of sterols (squalene, lanosterol, ergosterol, carotenoid, and
polyprenols) and analyzed the key and limited enzymes in these processes. Although
various sterols are identified in nature, their basic synthesis pathways appear to be
conserved. Squalene is the key intermediate in the biosynthesis of sterols, and the
cyclization of squalene into lanosterol (animals and fungi) or cycloartenol (plants),
producing various types of terpenoids. In addition to the synthesis processes of sterols,
how to enhance sterols production was also discussed, which provides the strategy for
the industrial production of sterol products.