    4.3.1.19 | synthesis |
production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from a single unrelated carbon source via threonine biosynthesis in Escherichia coli, by overexpression of threonine deaminase, which is the key factor for providing propionyl-coenzyme A (propionyl-CoA), from different host bacteria, removal of the feedback inhibition of threonine by mutating and overexpressing the thrABC operon in Escherichia coli, and knock-out of the competitive pathways of catalytic conversion of propionyl-CoA to 3-hydroxyvaleryl-CoA. Construction of a series of strains and mutants leads to production of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer with differing monomer compositions in a modified M9 medium supplemented with 20 g/liter xylose. The largest 3-hydroxyvalerate fraction obtained in the copolymer is 17.5 mol% |
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