The disclosure provides recombinant bacterial host cells that metabolize and convert glycerol or volatile fatty acids (VFAs) to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV. The disclosure further provides methods of producing PHBV using the recombinant bacteria disclosed herein.

Provided are a genetically engineered strain for producing polylactic acid and a method for producing polylactic acid. The genome of the genetically engineered strain is integrated with a coding sequence of exogenous D-lactate dehydrogenase gene, a coding sequence of exogenous propionyl-CoA transferase gene, and a coding sequence of exogenous polyhydroxyalkanoate synthase gene, enabling the genetically engineered strain to express exogenous D-lactate dehydrogenase, exogenous propionyl-CoA transferase, and exogenous polyhydroxyalkanoate synthase. The method includes: providing the above genetically engineered strain of Synechococcus elongatus; introducing carbon dioxide and culturing the genetically engineered strain under light; and when a growth OD of the genetically engineered strain reaches the maximum, collecting and drying the genetically engineered strain, and recycling the polylactic acid in the strain.

The present invention relates to a recombinant yeast cell comprising a gene encoding a protein exhibiting lactyl-CoA synthase activity and a gene encoding a protein exhibiting lactyl-CoA polymerase activity, said recombinant cell having the ability of producing polylactic acid (PLA), and the uses thereof.

Described are methods for the production of isobutene comprising the enzymatic conversion of 3-methylcrotonic acid into isobutene wherein said 3-methylcrotonic acid is obtained by the enzymatic conversion of 3-methylcrotonyl-CoA into 3-methylcrotonic acid or wherein said 3-methylcrotonic acid is obtained by the enzymatic conversion of 3-hydroxyisovalerate (HIV) into 3-methylcrotonic acid. It is described that the enzymatic conversion of 3-methylcrotonic acid into isobutene can, e.g., be achieved by making use of a 3-methylcrotonic acid decarboxylase, preferably an FMN-dependent decarboxylase associated with an FMN prenyl transferase, an aconitate decarboxylase (EC 4.1.1.6), a methylcrotonyl-CoA carboxylase (EC 6.4.1.4), or a geranoyl-CoA carboxylase (EC 6.4.1.5).

The present disclosure relates to a novel method for preparing poly(3-hydroxybutyrate-co-4-hydroxybutyrate), a microorganism using the biosynthetic pathway of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) of the present disclosure, a composition for producing poly(3-hydroxybutyrate-co-4-hydroxybutyrate), and a method for regulating the 4-hydroxybutyrate content of poly(3-hydroxybutyrate-co-4-hydroxybutyrate).

A system for carbon fixation is provided. The system comprises enzymes which catalyze reactions of a carbon fixation pathway, wherein at least one of the reactions of the carbon fixation pathway is a carboxylation reaction, wherein products of the reactions of the carbon fixation pathway comprise oxaloacetate and malonyl-CoA, wherein an enzyme which performs the carboxylation reaction is selected from the group consisting of phophoenolpyruvate (PEP) carboxlase, pyruvate carboxylase and acetyl-CoA carboxylase and wherein an export product of the carbon fixation pathway is glyoxylate. Additional carbon fixation pathways are also provided and methods of generating same.

Provided is a bacterial strain having a mutation in the gene that codes for monofunctional peptidoglycan transglycosylase (MtgA), wherein the mutation inactivates MtgA or reduces the activity of MtgA in comparison to a control strain lacking the mutation.

Provided is a mutant of propionyl-CoA transferase from Clostridium propionicum that can convert lactate into lactyl-CoA with high efficiency in a method of preparing a polylactate (PLA) or PLA copolymer using microorganisms. Unlike conventional propionyl-CoA transferase which is weakly expressed in E. coli, when a mutant of propiony-CoA transferase from Clostridium propionicum is introduced into recombinant E. coli, lactyl-CoA can be supplied very smoothly, thereby enabling highly efficient preparation of polylactate (PLA) and PLA copolymer.

Provided are microorganisms for making polyhydroxylalkanoate (PHA) compounds. For instance, the microorganism can include a polyhydroxylalkanoate (PHA) synthase (phaC) gene and one or both of an isocaprenoyl-CoA:2-hydroxyisocaproate CoA-transferase (hadA) gene and a propionate CoA-transferase (pct) gene. In some cases, the species of the microorganism is a Cupriavidus necator bacteria that has been genetically modified to include the PHA and hadA or pct genes.

Provided are a recombinant Ralstonia eutropha capable of producing polylactate or a hydroxyalkanoate-lactate copolymer, and a method of preparing polylactate or a hydroxyalkanoate-lactate copolymer using the same. The recombinant Ralstonia eutropha, which is prepared by introducing a gene of an enzyme converting lactate into lactyl-CoA and a gene of a polyhydroxyalkanoate (PHA) synthase using lactyl-CoA as a substrate thereto, may be cultured, thereby efficiently preparing a lactate polymer and a lactate copolymer.