Q. Wu, X.-Y. Lu, Z. Zheng, Y.-Z. Qiu, J.-Y. Chen, S.-P. Ouyang, and G.-Q. Chen*

Department of Biological Sciences and Biotechnology,

 Tsinghua University, Beijing 100084, China

The study of biosynthesis and applications of polyhydroxyalkanoates (PHA) involves knowledge in biology, chemistry, physics, chemical engineering, polymer chemistry and material sciences. Starting with the screening of PHBHHx producing bacteria using the FT-IR methodology, we were able to find that at least 30% of the bacteria we isolated were able to produce various PHA. With the help of chemical engineers, one of the isolated strain Aeromonas hydrophila was used to develop small scale fermentation process for production of copolyesters (PHBHHx) consisting of 3-hydroxybutyrate (3HB) and 10-15% 3-hydroxyhexanoate (3HHx). Molecular biology study showed that the A. hydrophila strain contained a specific PHBHHx synthase that only made 10-15% 3HHx in the PHBHHx. The introduction of other PHA synthase genes including phaP, phaJ and phaC, as well as hemoglobin gene vgb into the A. hydrophila strain, combined with the changing of growth conditions, allowed the manipulation of PHBHHx composition. PHBHHx consisting of various 3HHx were successfully produced and were found to affect not only the physical properties but also the biocompatibility and biodegradability that are important for biomaterial applications. Recent results showed that biodegradation of PHA that releases monomers can be a very important factor affecting cellular attachment, differentiation and proliferation. The close involvement of organic chemists helps create PHA with novel monomer structures that meet different types of applications.

 论文来源：International Symposium on Biological Polyesters ,Auguest 22-27, 2004