Biosynthesis of polyhydroxyalkanoates co-polymer in E. coli using genes from Pseudomonas and Bacillus.
Expression of Pseudomonas aeruginosa genes PHA synthase1 (phaC1) and (R)-specific enoyl CoA hydratase1 (phaJ1) under a lacZ promoter was able to support production of a copolymer of Polyhydroxybutyrate (PHB) and medium chain length polyhydoxyalkanoates (mcl-PHA) in Escherichia coli. In order to improve the yield and quality of PHA, plasmid bearing the above genes was introduced into E. coli JC7623, harboring integrated beta-ketothiolase (phaA) and NADPH dependent-acetoacetyl CoA reductase (phaB) genes from a Bacillus sp. also driven by a lacZ promoter. The recombinant E. coli (JC7623ABC1J1) grown on various fatty acids along with glucose was found to produce 28-34% cellular dry weight of PHA. Gas chromatography and (1)H Nuclear Magnetic Resonance analysis of the polymer confirmed the ability of the strain to produce PHB-co-Hydroxy valerate (HV)-co-mcl-PHA copolymers. The ratio of short chain length (scl) to mcl-PHA varied from 78:22 to 18:82. Addition of acrylic acid, an inhibitor of beta-oxidation resulted in improved production (3-11% increase) of PHA copolymer. The combined use of enzymes from Bacillus sp. and Pseudomonas sp. for the production of scl-co-mcl PHA in E. coli is a novel approach and is being reported for the first time.
Davis
Reeta
R
Department of Plant Cell Biotechnology, Central Food Technological Research Institute, Mysore 570020, India.
Anilkumar
P K
PK
Chandrashekar
A
A
Shamala
T R
TR
D000102:Acetyl-CoA C-Acyltransferase / Q000235:genetics / Q000378:metabolism; D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D018533:Biomass; D001704:Biopolymers / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D053898:Biosynthetic Pathways; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D015870:Gene Expression; D005818:Genetic Engineering / Q000379:methods*; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D011549:Pseudomonas / Q000201:enzymology* / Q000235:genetics
D001426:Bacterial Proteins; D001704:Biopolymers; D054813:Polyhydroxyalkanoates; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; D000217:Acyltransferases; C077225:poly(3-hydroxyalkanoic acid) synthase; D000102:Acetyl-CoA C-Acyltransferase