Abstract: A polyhydroxyalkanoate-producing microorganism is cultured to obtain microbial bodies accumulating polyhydroxyalkanoate particles and having an average cell size of 2 ?m or more. The microbial bodies are subjected to a heat treatment at a temperature higher than a temperature in the culturing to increase an average particle size of the polyhydroxyalkanoate particles in the microbial bodies. The resulting average particle size is equal to or greater than 1.8 ?m and equal to or smaller than the average cell size. The microbial bodies subjected to the heat treatment can be disrupted to obtain a cell disruption solution. The PHA particles can be separated from an aqueous phase of the cell disruption solution.

Abstract: Provided is a transformed microorganism that has a polyhydroxyalkanoate synthase gene and in which expression of an A1386 gene and/or an A2405 gene is reduced. In the transformed microorganism, expression of a minC gene and a minD gene may be enhanced. Also provided is a method of producing a PHA, the method including the step of culturing the transformed microorganism in the presence of a carbon source.