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Biosynthesis of poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) containing a predominant amount of 3‐hydroxyvalerate by engineered E scherichia coli expressing propionate‐ C o A transferase
Author(s) -
Yang Y.H.,
Brigham C.J.,
Song E.,
Jeon J.M.,
Rha C.K.,
Sinskey A.J.
Publication year - 2012
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2012.05391.x
Subject(s) - polyhydroxyalkanoates , escherichia coli , ralstonia , propionate , cupriavidus necator , metabolic engineering , strain (injury) , chemistry , copolymer , substrate (aquarium) , monomer , biochemistry , protein engineering , biodegradation , polymer , bacteria , enzyme , food science , organic chemistry , biology , gene , ecology , genetics , anatomy
Aims Of the biodegradable polyhydroxyalkanoates ( PHA s), poly(hydroxybutyrate‐ co ‐hydroxyvalerate) ( P ( HB ‐ co ‐ HV )) is often considered for fabrication of biocompatible and absorbable medical devices and other applications. Depending on the application, however, specific mechanical or processing properties must be improved. To address these required properties, we sought to alter the monomer composition of the copolymer by a combination genetic engineering in an E scherichia coli host and carbon substrate feeding. Methods and Results We applied a new method of 3‐hydroxyvalerate (3 HV ) monomer synthesis to produce a co‐polymer by the introduction of a propionyl‐ C o A transferase gene ( pct ), along with PHA biosynthetic genes bktB , phaB and phaC from R alstonia eutropha into engineered E . coli to produce P ( HB ‐ co ‐ HV ). The resulting strain successfully produced the copolymer containing an ultra‐high 3 HV monomer composition (over 80 wt%). Conclusions To the best of our knowledge, the P ( HB ‐ co ‐ HV ) production strain constructed here synthesized polymer with the highest 3 HV content of any engineered E . coli strain. This strain could also produce P ( HB ‐ co ‐ HV ) with the use of lower concentrations of propionate in the growth medium, compared to other reported strains, which could avoid the known growth inhibition from propionate in E . coli . Significance and Impact of the Study Polyhydroxyalkanoates have been emphasized as a potential alternative for petroleum‐based plastics by virtue of their physical properties and environmentally friendly characteristics. The copolymer produced in this work validates our genetic engineering approach and suggests that the Pct enzyme is a more efficient method for production of propionyl‐ C o A , the 3‐hydroxyvaleryl‐ C o A precursor.