PHA synthesis in
Rhodospirillum rubrum is similar to A. eutrophus with minor
modifications in the second step. The acetoacetyl-CoA
is reduced by an NADH-dependent reductase to L( +)-3-
hydroxybutyryl-CoA, which is then converted to D( -)-3-
hydroxybutyryl-CoA by two enoyl-CoA hydratases. ' 17,''*
P. oleovorans and most pseudomonads belonging to the
rRNA homology group I synthesize MCL-PHA from various
MCL-alkanes, alkanols, or a l k a n ~ a t e s .I~t w~a,s~ s~ug -
gested that the 3-hydroxyacyl-CoA intermediates of the
P-oxidation pathway are channeled to PHA synthesis.92
This is referred to as the P. oleovorans PHA biosynthetic
pathway. Most pseudomonads belonging to rEWA homology
group I except P. oleovorans also synthesize MCLPHAs
from acetyl-CoA via fatty-acid biosynthetic pathway
,593663169w hich is referred to as the Pseudomonas
aeruginosa PHA biosynthetic pathway.