This study was on isolation, purification and characterization of PHB from Vibrio mimicus strain isolated from sediment samples collected from Vellar estuary, Parangipettai. PHB produced from the cells that were grown at mass scale level under optimized growth parameters were used in the present study. The FT-IR analysis showed the presence of CH 2 -CH 3 -C=0 methyl esters in the extract and it also confirmed that the isolated product as PHB. Regarding degradation in the present work the complete bioplastic degradation i.e. 100% degradation was observed in 49 days at 35 o C, followed by 94% and 88% degradation at 30 o C and 25 o C respectively in 49 days of incubation whereas the least degradation was observed at 40 o C.

In the present investigation different strains which showed the accumulation of PHB in the nitrogen deficient medium were isolated from sediment samples collected from Vellar estuary (Lat 11 o 29'24"N and Long. 79 o 45' 36" E). Among these Vibrio mimicus which showed the maximum PHB accumulation was selected for further study. The optimum growth conditions of V. mimicus were 36 hrs of incubation period, 35C, pH-8, 1% NaCl, 4% glucose and 0.03% yeast extract. Mass scale was done by keeping the above ideal parameters; which resulted in 18.6g/L of PHB production on dry weight basis.