Introducing a new bioengineered bug: Methylobacterium extorquens tuned as a microbial bioplastic factory

Discussion on and use of methanol as chemical feedstock and as alternative fuel has gained momentum during the past years. Consequently, microorganism and product design based on ''methylotrophism'' is in vogue as reflected by increasing research and development activities in methanol-related areas. A recent example of microorganism and product development is the use of recombinant Methylobacterium extorquens ATCC 55366 strains in the production of second generation biopolyesters. Feeding n-alkenoic acids in addition to methanol yielded functionalized polyhydroxyalkanoates (PHAs) and uncovered how M. extorquens copes with fatty acids. While some parts of the degradation pathway remain unclear, possible metabolic routes are suggested that may explain the significant loss of double bonds prior to polymerization of PHA precursors and occurrence of odd-numbered monomers derived from even-numbered n-alkenoic acids. In addition, microbial discoloration upon fatty acid feeding is discussed and future directions for further genetic modification of M. extorquens are provided.