Abstract
For decades, polyhydroxyalkanoates (PHA) have been touted as a bio-based, biodegradable alternative to "traditional" chemical-based plastics. PHA are synthesized and degraded by a variety of different microorganisms, and many have been found to possess thermal and mechanical properties similar to some types of widely used synthetic plastics. However, one of the main hurdles for large-scale PHA production and subsequent use in day-to-day applications has been the price of feedstocks (raw materials) required for synthesis. Suitable carbon and energy sources must be used for optimal microbial growth and polymer production. Refined carbon sources tend to be very costly, especially in quantities that would be required for large-scale PHA syntheses. In recent years, PHA synthesis efforts have turned to waste streams as sources of carbon and energy for microbial growth and polymer synthesis. Industries, such as agriculture and food processing, produce a large amount of waste that is not fit for human consumption but can be made bioavailable for microbial activities. This chapter discusses efforts in using available industrial waste materials as inexpensive feedstocks for PHA production, the types of polymers made as a result of these efforts, and the possibility of scaling-up these efforts to make large-scale PHA production feasible.