Pathway VI employs putative lactonase and hydroxyacyl-CoA synthase to turn
4,5-alkanolactone into 4,5-hydroxyacyl-CoA for PHA synthesis (Valentin and
Steinbüchel 1995). Pathway VII is based on the putative alcohol dehydrogenase
found in A. hydrophila 4AK4. In pathway VII, 1,4-butanediol is oxidized to
4-hydroxybutyrate, then to 4-hydroxybutyryl-CoA for 4-hydroxybutyratecontaining
PHA synthesis (Xie and Chen 2008). Pathway VIII turns 6-hydroxyhexanoate
into 6-hydroxyhexanoate-containing PHA under the actions of eight
enzymes (Table 1).