ABSTRACT
Depending on the substrate provided, many microorganisms can include a wide variety of 3-hydroxy fatty acids in the potential bacterial polyhydroxyalkanoate (PHA). More than 100 different monomer units have been identified as constituents of PHA in >300 different microorganisms. Microorganisms can produce intracellular PHA inclusions in their stationary growth phase under nutritional unbalanced growth conditions but an excess of carbon source. Different types of enzymes are involved in running the metabolic process of the bacteria for the formation of the inclusion bodies. Depending on functions, the main key enzymes involved in the PHA biosynthesis are categorized into three. The key enzyme in PHA biosynthesis is PHA synthase which mainly polymerize the monomeric groups of carbon source intake by the microorganisms. The second type of enzyme is β-ketothiolase which is involved in the intermediate metabolic pathway program. The third type of enzyme is acetoacetyl CoA reductase which basically reflects the main role in oxidation-reduction reaction in PHA metabolism process.
