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Overexpression of succinyl‐CoA synthase for poly (3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) production in engineered Escherichia coli BL 21( DE 3)
Author(s) -
Bhatia S.K.,
Yi D.H.,
Kim H.J.,
Jeon J.M.,
Kim Y.H.,
Sathiyanarayanan G.,
Seo H.M.,
Lee J.H.,
Kim J.H.,
Park K.,
Brigham C.J.,
Yang Y.H.
Publication year - 2015
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/jam.12880
Subject(s) - metabolic engineering , engineering education , computer science , engineering , chemistry , enzyme , mechanical engineering , biochemistry
Abstract Aim This study aims to increase the 3‐hydroxyvalerate (3 HV ) fraction in poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) [P( HB ‐ co ‐ HV )] using succinyl‐CoA synthase. Methods and Results Escherichia coli YH 090, a polyhydroxyalkonate ( PHA )‐producing strain, was further engineered for overexpression of succinyl‐CoA synthase genes ( suc CD ), and examined for P( HB ‐ co ‐ HV ) copolymer production in the presence of various precursor molecules using mixture analysis. Glycerol, succinate and propionate were screened as important factors for controlling intracellular PHA accumulation and monomer composition. Glycerol concentrations exerted the greatest influence on the overall biomass concentration and the intracellular PHA content, while propionate concentrations in the presence of succinate influenced the 3 HV content of the copolymer. Mixture analysis also demonstrated that the engineered strain has the capacity to accumulate up to 80% of its cell dry weight ( CDW ) as PHA with a variable fraction of 3 HV monomer (maximum of 72 wt %) depending on the controlled conditions. Conclusions Propionate is the principal precursor for 3 HV monomer in P( HB ‐ co ‐ HV ) biopolymer and its utilization requires conversion to propionyl‐CoA. Engineered E. coli YHY 99, overexpressing suc CD genes, leads to an increase of the succinyl‐CoA pool, which enhances the conversion rate of propionate by providing a CoA supply to other acyltransferase enzymes that have a role in propionate utilization. Significance and Impact of the Study Engineered E. coli YHY 99 was able to utilize propionate with a 4·5‐fold increase in rate, as compared to the control strain, and resulted in the synthesis of a copolymer with high 3 HV monomer content.