PHAscl

There are only very few PHA synthases which can incorporate 3HASCL as well as 3HAmcl into the accumulated PHAs. Examples are the PHA synthases of T. pfennigii and Aeromonas caviae, which synthesize, for example, copolyesters of 3HB, 3HHx plus 3HO [26], or of 3HB plus 3HHx [59], from fatty acids, respectively. Recently it was found that the type I-PHASCL synthase of R. eutropha also conferred the incorporation of 3HHx [60] or of 3HO plus 3HD [61] into PHAs in addition to 3HB to certain recombinant strains of enterobacteria. 

Separation of PHASCL and PHAMCL into two separate granules within the same cell often seems to occur if two different PHA synthases with non-overlapping substrate ranges are present in the cell. Obviously, each type of PHA synthase participates separately in the initiation of micelle formation of nascent PHA granules, because only PHA molecules of similar structure, which remain bound to the PHA synthase protein, can contribute to the formation of a micelle. When the granules become larger, further PHA synthase molecules can only bind to the surface of the granules if they represent the same type of PHA synthase. 

Ralstonia eutropha, PHAscl in, 20 257-258 Ralstonite, 2 364t Ralston Purina extruders, 10 850 RAM (reliability, availability,... 

PHAscl (short chain length monomer unit consisting of up to five carbon atoms)... 

A key precursor to multidentate arsines is o-bromophenyldichloroarsine, which may be similarly obtained if the diazotization is conducted in glacial acetic acid and the source of arsenic is AsCl (equation 34).107,10 Conproportionation of PhAsCl, and PhAsO gives Ph2AsCl (contaminated with PhAsCl2 and PhjAs).106... 

Polyhydroxyalkanoates can be synthesized in vitro in cell-free systems with purified PHA synthase protein. This has been demonstrated several times not only with different PHASCL synthases [34-37] but also with PHAMCL synthases [38]. 

At present, Metabolix Inc (Cambridge, MA) andTepha Inc (Lexington, MA) are most probably the most advanced companies in this area. Metabolix has build together with Archer Daniels Midland Company (ADM) a new plant in Clinton (Iowa) to produce about 50000 tons per year of various PHAScl for bulk applications. Tepha is focusing on the production of various sophisticated medical devices like sutures, cardiovascular tissues, meshes etc. 

CEHKAB Z. Natuiforsch., TeilB, 1984, 39,139. PHASCL Acta Crystallogr, Sect. B, 1981, 37,1357. 

Several PHA producing microorganisms as well as several types of PHA were discovered. " The whole PHA family can be sub-divided into three main categories the short-chain length PHA (PHAscl), the medium-chain length PHA (PHAmcl) and rarer PHA (Figure 1.1). The structural differences inside the PHA family imply deep differences in their thermo-mechanical... 

---