Dear J Yadav,

         We have been working in the area of PHA since last 6 years.

In brief, harvest the bacterial cells and wash the pellet superficially with a little volume of chloroform. Subsequently, you may add 10 volumes of chloroform (warm, 60 degree C) to dissolve the pellet, vortex rigorously. This step allows to disrupt the cell membranes and let the PHA come out in chloroform. 

Filter the chloroform solution (and keep the solution in round bottom flask) and evaporate it using Rotavapor/distillation.

Add chilled methanol to get the PHA film. For high purity, you may again dissolve the extracted film (dried) in chloroform and precipitate in methanol.

[Note: Although it is a crude method, but valid for both Gram +ve and -ve bacteria with 95% extraction capacity of the total PHA]

I hope this would be of help, you may see our articles for other necessary reference (see google scholar link/research-gate).

Regards

Prasun Kumar, Ph.D.

Google Scholar: http://scholar.google.co.in/citations?user=SsvE3W8AAAAJ&hl=en&oi=ao

Researchgate: https://www.researchgate.net/profile/Prasun_Kumar2

http://aem.asm.org/content/65/6/2762.full

an useful article