The purpose of the present invention is to provide a PHA, in particular PHBV, having a molecular weight exceeding 3,610,000 and/or a method for producing such a PHA while controlling the molecular weight thereof. Provided is a copolymer of random copolymerization of 3-hydroxybutanoic acid and 3-hydroxyvaleric acid, having a weight-average molecular weight exceeding 3,610,000.

A biofilm process is disclosed for treating wastewater containing readily biodegradable dissolved organic matter GP (measured as chemical oxygen demand or COD) and producing surplus biomass from the biofilm process that includes an enhanced polyhydroxyalkanoate (PHA) content. The process comprises directing a wastewater influent containing the readily biodegradable COD (RBCOD) into a biofilm unit process. The PHA content of surplus biomass is enhanced by controlling for a decreased biofilm process specific organic loading rate in combination with controlling phosphorus loading rates relative to the process RBCOD loading rates: (1) controlling the wastewater influent phosphorus loading rate to the biofilm unit process includes maintaining an average RBCOD/P ratio of the influent that is between 200 and 800 g/g; (2) decreasing the process specific organic loading rate includes producing a biofilm unit process effluent having readily separable mixed liquor volatile suspended solids (RS-MLVSS); and (3) separating a portion of the RS-MLVSS from the biofilm unit process effluent and recycling at least a portion of the separated RS-MLVSS back to the biofilm unit process. The combination of the RBCOD/P control and specific loading rate control maintains, on average, the surplus biomass with a PHA content that is greater than 30% gPHA/g VSS.

Embodiments of the invention relate generally to methods to generate microorganisms and/or microorganism cultures that exhibit the ability to produce polyhydroxyalkanoates (PHA) from carbon sources at high efficiencies. In several embodiments, preferential expression of, or preferential growth of microorganisms utilizing certain metabolic pathways, enables the high efficiency PHA production from carbon-containing gases or materials. Several embodiments relate to the microorganism cultures, and/or microorganisms isolated therefrom.

The purpose of the present invention is to provide a method for enhancing the production quantity of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HH)) having a high fraction of 3-hydroxyhexanoate (3HH) using a saccharide or glycerol as a starting material. The present invention provides: a method for producing a P(3HB-co-3HH) copolymer including performing transformation by homologous recombination of a crotonyl-CoA reductase gene in a chromosome of a recombinant strain of Cupriavidus necator endowed with the ability to produce P(3HB-co-3HH), or performing transformation by introducing an autonomous replication vector in which the crotonyl-CoA reductase gene is incorporated in the aforementioned strain, and cultivating the transformant in a medium containing a saccharide or glycerol as a carbon source; and a method for enhancing the production quantity of the copolymer and/or the fraction of 3HHx in the copolymer.

The present application provides: a transformed microorganism for producing a PHA copolymer containing 3HH monomer unit at a higher composition ratio, specifically, a transformed microorganism comprising a PHA synthase gene capable of synthesizing a PHA copolymer containing 3HH monomer unit and a gene encoding a protein having (R)-specific enoyl-CoA hydratase activity, characterized in that, in the transformed microorganism, the expression of a gene encoding at least one β-ketothiolase enzyme having thiolysis activity for β-keto-(C6) acyl-CoA (i.e., β-ketohexanoyl-CoA) is inhibited, thereby losing or reducing the enzyme activity; and a method for producing a PHA copolymer containing 3HH monomer unit, comprising a step of culturing the transformed microorganism.

The present application provides: a transformed microorganism for producing a PHA copolymer containing 3HH monomer unit at a higher composition ratio, specifically, a transformed microorganism comprising a PHA synthase gene capable of synthesizing a PHA copolymer containing 3HH monomer unit and a gene encoding a protein having (R)-specific enoyl-CoA hydratase activity, characterized in that, in the transformed microorganism, the expression of a gene encoding at least one β-ketothiolase enzyme having thiolysis activity for β-keto-(C6) acyl-CoA (i.e., β-ketohexanoyl-CoA) is inhibited, thereby losing or reducing the enzyme activity; and a method for producing a PHA copolymer containing 3HH monomer unit, comprising a step of culturing the transformed microorganism.

Provided is a method for preparing a block copolymer including a step of subjecting a lactide monomer to ring-opening polymerization in the presence of a biosynthesized poly(3-hydroxypropionate) initiator to prepare a polylactide-poly(3-hydroxypropionate) block copolymer.

Provided is a method for preparing a block copolymer including a step of subjecting a lactide monomer to ring-opening polymerization in the presence of a biosynthesized poly(3-hydroxypropionate) initiator to prepare a polylactide-poly(3-hydroxypropionate) block copolymer.

Described here is a method for increasing the transfer of a gas substrate in microbial fermentation, comprising incubating an emulsion comprising an oil phase and an aqueous phase droplet dispersed in the oil phase, and supplying the gas substrate to the oil phase, wherein the aqueous phase droplet comprises a microorganism, and wherein the emulsion is stabilized by a surfactant or an amphiphilic particle that is adsorbed to an interface of the oil phase and the aqueous phase. Also described is an emulsion for microbial fermentation, comprises an oil phase and an aqueous phase droplet dispersed in the oil phase, wherein the aqueous phase droplet comprises a microorganism, wherein the emulsion comprises a gas substrate externally-supplied to the oil phase, and wherein the emulsion is stabilized by a surfactant or an amphiphilic particle that is adsorbed to an interface of the oil phase and the aqueous phase.

Embodiments of the invention relate generally to processes for the production and processing of polyhydroxyalkanoates (PHA) from carbon sources. In several embodiments, PHAs are produced at high efficiencies from carbon-containing gases or materials.