A Research team has discovered a bacteria (Pseudonomas Putida) which could convert styrene, an inherently toxic monomer of polystyrene (PS), to produce polyhydroxyalkanoate (PHA), a biodegradable plastic: the bacteria converts the styrene into simple carbon units which are then polymerized to form PHA. According to the researchers, the biodegradable plastic thus obtained can be used in a wide range of applications including medical implants, scaffolds for tissue engineering, heat resistant plastic, etc. The team is improving the converting process before its commercialization.

A medium chain length polyhydroxyalkanoate (mclPHA, monomers from C6-C14) is a water insoluble, biodegradable and biocompatible polymer that it is well suited for medical applications. For this purpose the polymer needs to be highly pure, especially with respect to pyrogenic compounds. Most commonly mclPHA is produced by certain Gram-negative bacteria like Pseudomonas putida. To obtain pure PHA, the intracellular PHA-inclusion bodies must be separated from the other cell components. The cells first have to be disrupted and then the PHA-granules can be isolated. However, cell components like nucleic acids, lipids, proteins etc. can contaminate the PHA. Especially lipopolysaccharides (LPS) from the outer cell membrane are the main culprit for pyrogenic contamination A very small amount of LPS causes serious problems in pyrogenic contamination

Several recovery processes have been established for short chain length PHA (sclPHA, C2-C5 monomer) that has quite different physical properties compared to mclPHA, whereas less attention has been paid to the recovery of mclPHA.
In general recovery processes can be divided into two categories: solvent extractions and aqueous digestions. Both have to fulfill several conditions: high purity of the end product, avoidance of halogenated solvents, no degradation of the polymer and high efficiency.

(Based on research conducted by an Irish researchers team at the Dublin's University College (UCD))