Biosynthetic and biodegradable polyesters from renewable resources: Current state and prospects

Bacterial poly(hydroxyalkanoate)s (PHA) are a complex class of polyesters, and almost one hundred different constituents are currently known. Unfortunately, most of these constituents only occur in the polyesters if specific precursor substrates are provided as carbon source. Recently, however, bacteria and mutants were isolated, which synthesize PHA exhibiting an interesting composition from simple unrelated substrates obtainable from renewable resources provided by the agriculture. This contribution will provide an example how PHA based on 4-hydroxyvaleric acid can be obtained from bulk chemicals. In addition, some aspects of our current knowledge on the physiological and molecular basis of PHA biosynthesis will be provided.