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.

The present invention relates to the technical field of microorganisms, and specifically to engineered microorganisms expressing acetoacetyl-CoA reductase variants and methods for increasing the proportion of 3-hydroxyhexanoic acid in PHA. The acetoacetyl-CoA reductase variants and their coding genes provided by the present invention can significantly increase the proportion of 3-hydroxyhexanoic acid in PHA produced by strains; the proportion of 3-hydroxyhexanoic acid in PHA produced by the engineered Ralstonia eutropha constructed utilizing the acetoacetyl-CoA reductase variants and their coding genes provided by the present invention is significantly increased, which provides new genes and strain resources for strains producing poly(3-hydroxybutyrate-co-3-10 the development of engineered hydroxyhexanoate) with high proportion of 3-hydroxyhexanoic acid.

Construction and expression of synthetic pathways to produce (S) or (R)-3-hydroxybutyrate (3HB) as enantiomerically-pure products by genetically engineering cyanobacterium Synechocystis sp. PCC 6803. Under optimized growth conditions, the pathway employing phaA and phaB from R. eutropha was the most effective, producing up to 533.45.5 mg/l (R)-3HB after 21 days photosynthetic cultivation. For the first time, the feasibility and high efficiency of producing 3HB using solar energy and CO.sub.2 as sole energy and carbon sources by engineered cyanobacteria is demonstrated.

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.

This disclosure relates to the field of bacterial strains and their ability to degrade lignocellulosic biomass. In a preferred embodiment, the present disclosure is directed to a Geobacillus sp. strain. Notably, we have found that the Geobacillus sp. strain has the capability to simultaneously hydrolyze and ferment lignocellulosic biomass to form polyhydroxyalkanoate (PHA). Most preferably, the hydrolysis and fermentation to form PHA takes place in a single step.

Construction and expression of synthetic pathways to produce (5) or (R)-3-hydroxybutyrate (3HB) as enantiomerically-pure products by genetically engineering cyanobacterium Synechocystis sp. PCC 6803. Under optimized growth conditions, the pathway employing phaA and phaB from R. eutropha was the most effective, producing up to 533.45.5 mg/l (R)-3HB after 21 days photosynthetic cultivation. For the first time, the feasibility and high efficiency of producing 3HB using solar energy and CO.sub.2 as sole energy and carbon sources by engineered cyanobacteria is demonstrated.

The present disclosure provides a microorganism and expression cassette useful for biologically producing PHA ho-mopolymers and/or PHA copolymers, including PHB-co-MCL copolymers of controllable or predetermined composition. In embodiments, the present disclosure provides a nucleic acid construct suitable for use in a microorganism and/or expression cassette including a nucleic acid construct including: one or more genes comprising a phaJ4 gene, a phaA gene, a phaB gene, a phaC1 gene, or combinations thereof; a cDNA that encodes one or more proteins comprising an enoyl-CoA hydratase 2, a -ketothiolase, an acetoacetyl-CoA reductase, a type II poly hydroxyalkanoate synthase, or combinations thereof; or one or more nucleic acid sequences that encode one or more proteins including an enoyl-CoA hydratase 2, a -ketothiolase, an acetoacetyl-CoA reductase, a type II poly hydroxyalkanoate synthase, or combinations thereof.

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.

A method of manufacturing 1,4-butanediol through acetyl-CoA, acetoacetyl-CoA, 3-hydroxybutyryl-CoA, crotonyl-CoA, and 4-hydroxybutyryl-CoA by using a microbe and/or a culture thereof, wherein the microbe in the manufacturing method for 1,4-butanediol includes any one of genes among (a) a gene that has a base sequence of sequence number 1, (b) a gene that has a base sequence such that one or more bases are deleted, substituted, or added in a base sequence of sequence number 1, wherein the gene has a base sequence with an identity greater than or equal to 90% with respect to the base sequence of sequence number 1, and (c) a gene that hybridizes with a gene that has a base sequence complementary with a gene that has a base sequence described in sequence number 1 on a stringent condition, and includes any one or more genes among (d) genes that have base sequences of sequence numbers 2 to 9, (e) genes that have base sequences such that one or more bases are deleted, substituted, or added in base sequences of sequence numbers 2 to 9, wherein the genes have base sequences with an identity greater than or equal to 90% with respect to original base sequences thereof, and (f) genes that hybridize with genes that have base sequences complementary with genes that have base sequences of sequence numbers 2 to 9 on a stringent condition.

The present invention relates to the technical field of microorganisms, and specifically to engineered microorganisms expressing acetoacetyl-CoA reductase variants and methods for increasing the proportion of 3-hydroxyhexanoic acid in PHA. The acetoacetyl-CoA reductase variants and their coding genes provided by the present invention can significantly increase the proportion of 3-hydroxyhexanoic acid in PHA produced by strains; the proportion of 3-hydroxyhexanoic acid in PHA produced by the engineered Ralstonia eutropha constructed utilizing the acetoacetyl-CoA reductase variants and their coding genes provided by the present invention is significantly increased, which provides new genes and strain resources for strains producing poly(3-hydroxybutyrate-co-3-10 the development of engineered hydroxyhexanoate) with high proportion of 3-hydroxyhexanoic acid.