(589c) In Situ Characterization of Polyhydroxyalkanoates Using Surface-Enhanced Raman Spectroscopy

Polyhydroxyalkanoates (PHAs) are increasingly used in applications ranging from biodegradable packaging to biomedical applications. Different strains of naturally occurring and genetically modified bacteria produce PHAs as energy storage compounds to sustain life through carbon-limited environmental fluctuations.  Optimization of both polymer production and polymer properties, however are limited due to the limitations of traditional characterization techniques such as gas chromatography and transmission electron microscopy to quantitatively determine the presence and composition of PHAs in situ. Here we report the application of surface-enhanced Raman spectroscopy (SERS) for rapid determination of PHA formation within living bacteria Cupriavidus necator, both within a single bacterium and throughout a sizable sample of population permitting evaluations of sample heterogeneity. In addition to rapid determination of presence of PHAs, we can also determine whether the polymer granules inside the bacteria are crystalline or amorphous in nature. This technique not only provides measurement tools for optimizing the production of biopolymers but also can be extended for monitoring the metabolic changes within living bacteria.