So there isn't a whole lot of point to the project, if we can't make filaments for 3d-printing from PHA!
Useful papers list:
Recent Advances in 3D Printing of Aliphatic Polyesters.
1kg of Polyhydroxyalkaonate granules is ~£215 from sigma aldrich
I've seen one PHA filament, called Z-PHA from zortrax. I guess the Z is because of their company name? (datasheet here https://cdn.zortrax.com/wp-content/uploads/2018/11/Z-PHA_Technical_Data_Sheet_eng.pdf Tg=62.58C) I've seen some PLA/PHA blends. So that's kinda promising.
Maybe a good starting point would be for me to go buy the granules, and try making filament from them using a filabot!