Conclusion
The amount of nitrogen source and types of co-substrates play significant role on the type of
copolymer accumulation in A. eutrophus. Regardless of the presence of co-substrate in the culture
media, same types of PHA copolymers [i.e., P(3HB-3HV) and P(3HB-4HB)] were produced as A.
eutrophus was cultivated in either nitrogen rich or limit media, whereas P3HB homopolymer was
synthesized as the nitrogen free medium was used. In the presence of nitrogen in the media,
P(3HB-co-3HV) was synthesized as propionic acid was used as co-substrate, while P(3HB-co-4HB)
was synthesized when acetatic/butyrate were used as co-substrate. Based on the present study,
the production of copolymer-type biopolyesters from glucose was fulfilled; however, in order to
obtain a low competitive cost of the biopolymer compared that of the petroleum based- polymers,
cheap and abundant glucose containing biomasses (e.g., rice straw, cassava pulp, bagasse) must
be utilized as a raw materials for the biopolyester production.