Accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), a well-known co-polymer of polyhydroxyalkanoates family, was investigated in a N2-fixing cyanobacterium, Aulosira fertilissima CCC 444, in presence
of propionate and valerate in the culturemedium.
The most significant rise in P(3HB-co-3HV) co-polymer content up to
77 % of dry cell weight was recorded under 0.5 % fructose+0.4 % valerate supplementation depicting a productivity of 38 mg L−1 day−1, which was further increased by 2.5-fold, i.e., up to 95 mg L−1 day−1 under P deficiency. Surface analysis revealed a regular and smooth surface for P(3HB-co-3HV) co-polymer, against rugged and porous surface
of the homopolymer of poly-β-hydroxybutyrate. X-ray diffraction showed semi-crystalline nature of the P(3HB-co-3HV)
copolymer.
The thermal and mechanical properties of the copolymer
are comparable with the chemoheterotrophic bacterial
polymers, thus opens up possibilities of using cyanobacterial
PHAs in various fields.