These are produced from 8 isoprene molecules and contain 40 carbon atoms and are also known as tetraterpenoids with polyisoprenoid
structure having a long conjugated double bond system forming the backbone of the molecule, which may be terminated by cyclic end groups that contain oxygen-bearing substitutes.
It is isolated from the neutral fraction of an extract of spruce needles and belongs to the group of polyprenols: polyisoprenoid
alcohols that are transformed into dolichols in the liver (Blogger et al.
Austin, a novel polyisoprenoid
mycotoxin from Aspergillus ustus.
Sterols are hydroxylated steroids, a class of polyisoprenoid
molecules found naturally in almost all living organisms.
The lipids can be saturated hydrocarbons, fatty acids such as stearic acid, or glycerides such as tristearin, polyisoprenoids
, or cholesterol.
"Bio-based polymers include various synthetic polymers derived from renewable resources and C[O.sub.2], biopolymers (nucleic acids, polyamides, polysaccharides, polyesters, polyisoprenoids
and polyphenols), their derivatives, and their blends and composites.
Polyhydroxyalkanoates, only recently appreciated as ranking with polysaccharides, proteins, polynucleotides and polyisoprenoids
as a class of physiologically important biopolymers, have brought a solution to the search for biodegradable plastics.