There are three kinds of known pathways for mcl-PHA synthesis,
found mostly in Pseudomonas species. Each pathway uses a
different substrate to create 3HAs, which are then used to synthesize
mcl-PHAs. All Pseudomonas spp. will only accept 3HAs of
6e14 carbon atoms. This is due to the specificity of PHA synthase,
the enzyme responsible for polymerization of hydroxyalkanoic acid
thioesters (Koller et al., 2010a).