Professor George Guo-Qiang CHEN received his BSc in Applied Chemistry from South China University of Science and Technology in 1985, PhD in Microbiology from Graz University of Technology, Austria in 1989. He then worked as post-doc at Nottingham University, UK and University of Alberta, Canada from 1990-1994. Beginning from 1994, he joined Tsinghua University, Beijing and subsequently became a faculty there. His research area is microbial metabolic engineering and synthetic biology.

Abstract

A Systematic Study on Microbial Production of Biopolymers and Chemicals

Polyhydroxyalkanoates (PHA) are a family of biopolymers produced by many bacteria, they are reported to have 150 hydroxyalkanoate monomers with various structures. PHA and its related technologies are forming an industrial value chain ranging from fermentation, materials, energy to medical fields. In most cases, bacteria produce copolymers consisting of at least two various different monomers such as copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV), copolymers of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx), and copolymers of 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate and 3-hydroxydodecanoate (short as medium-chain-length PHA copolymers). Through systematic study on PHA synthetic pathways and manipulating the relevant expressions on the genes, we have succeeded in producing homopolymers of 3-hydroxyvalerate (PHV), 3-hydroxyhexanoate (PHHx), 3-hydroxyheptanoate (PHHp), 3-hydroxyoctanoate (PHO), 3-hydroxydecanoate (PHD) and 3-hydroxydodecanoate (PHDD). These homopolymers demonstrate unusual properties compared with their copolymers. The systematic approach adopted in this study opens a new area for creating new materials for various applications.

In addition, we succeeded in cloning the 32 genes related to vitamin B12 synthesis from Pseudomonas putida KT2442. The 32 genes were turned into biobricks and joined by isocaudamers. Two large plasmids containing the 32 genes have been successfully transformed into E. coli for production of B12.

A systematic and synthetic approach can be useful for production of various industrial interesting products.

References

• Chen GQ. A Polyhydroxyalkanoates Based Bio- and Materials Industry.  Chem Soc Rev 38 (2009) 2434–2446
• Ouyang SP, Luo RC, Chen SS, Luo RC, Liu Q, Zheng M, Wu Q and Chen GQ. Production of Polyhydroxyalkanoates Containing High 3-Hydroxydodecanoate Monomer Content by fadB and fadA Knockout Mutant of Pseudomonas putida KT2442. Biomacromolecules  8 (2007) 2504-2511
• Wang HH and Chen GQ. Production and Characterization of Homopolymer Polyhydroxyheptanoate (P3HHp) by a fadBA knockout mutant Pseudomonas putida KTOY06 derived from P. putida KT2442. Process Biochem 44 (2009) 106–111
• Shen XW, Yang Y, Jian J, Wu Q and Chen GQ. Production and Characterization of Homopolymer poly(3-hydroxyvalerate) (PHV) Accumulated by Wild type and Recombinant Aeromonas hydrophila Strain 4AK4. Bioresource Technol 100 (2009) 4296–4299