The surface of a PHA granule is coated with a layer of
phospholipids and proteins. Phasins, a class of proteins,
are the predominant compounds in the interface of a
granule. The phasins influence the number and size of
PHA granules (Po¨tter et al. 2002; Po¨tter and Steinbu¨chel
2005). Expression of genes of phasins can be the 2 to closely
packed granules in bacterial cells.