Embodiments of the invention relate to the microbial production of polyhydroxyalkanoic acids, or polyhydroxyalkanoates (PHA), from substrates which cannot be used as a source of carbon and/or energy for microbial growth or PHA synthesis and which have microbial and environmental toxicity. According to one embodiment of the invention, a process for the production of PHA is provided wherein an enzyme such as methane monooxygenase is used to convert volatile organic compounds into PHA through the use of microorganisms that are unable to use volatile organic compounds as a source of carbon for growth or PHA production.