The invention relates to a plasmid, a DNA assembly method and its application recombinant strain. The plasmid has single adjacent Type IIP and Type IIS RE recognition sites. The plasmid combines the properties of Type IIP and Type IIS REs to achieve recursive cycling, SCAR-free and repeat sequence assembly.

Recombinant microbial cells are provided which have been engineered to produce fatty acid derivatives having linear chains containing an odd number of carbon atoms by the fatty acid biosynthetic pathway. Also provided are methods of making odd chain fatty acid derivatives using the recombinant microbial cells, and compositions comprising odd chain fatty acid derivatives produced by such methods.

The invention relates to a plasmid, a DNA assembly method and its application recombinant strain. The plasmid has single adjacent Type IIP and Type IIS RE recognition sites. The plasmid combines the properties of Type IIP and Type IIS REs to achieve recursive cycling, SCAR-free and repeat sequence assembly.

There is disclosed a mutant, non-naturally occurring or transgenic plant cell comprising: (i) a polynucleotide comprising, consisting or consisting essentially of a sequence encoding a threonine synthase and having at least 90% sequence identity to SEQ ID NO:1, SEQ ID NO:2 or SEQ ID NO:3 or at least 87% sequence identity to SEQ ID NO:4, or SEQ ID NO:5; (ii) a polypeptide encoded by any one of said polynucleotides set forth in (i); or (iii) a polypeptide having at least 95% sequence identity to SEQ ID NO:6, SEQ ID NO:7 or SEQ ID NO:8; or (iv) a construct, vector or expression vector comprising the polynucleotide as set forth in (i).

The present invention relates to the technical field of microbial engineering. Specifically disclosed are a recombinant microorganism, a method for constructing same and use thereof. According to the present invention, by means of constructing a phosphate acetyltransferase-inactivated strain and applying the strain to the production of threonine, the threonine-producing ability of the strain is remarkably improved, and the strain has a remarkably increased production of threonine as compared to an unmodified strain. Combined with attenuated expression or inactivation of acetate kinase, HTH-type transcriptional regulator and the like, as well as improved activity of pyruvate carboxylase and enzymes involved in a threonine synthesis-related pathway, the production of threonine is further improved. The described modifications can be used in the fermentative production of threonine and have relatively good application value.

The present invention provides a method for constructing a threonine-producing engineered bacterium. According to the present invention, a 2-methylcitrate synthase 1-inactivated strain (Corynebacterium) is applied to the production of threonine, and the production of threonine produced by the 2-methylcitrate synthase 1-inactivated strain is increased by about 42% compared with that produced by an unengineered strain. When the application of the 2-methylcitrate synthase 1-inactivated strain is further combined with enhanced expression of at least one of aspartate aminotransferase, aspartate kinase, homoserine dehydrogenase, threonine synthase, NAD kinase, fructose-1,6-bisphosphatase 2 and the like in the threonine synthesis pathway, the production of threonine is improved. The method provides a new way for large-scale production of threonine and has high application value.

Provided are a recombinant microorganism for producing threonine and the use thereof in the fermentation production of threonine or a derivative thereof. A 20-30 bp segment upstream of a start codon of a gene encoding phosphoenolpyruvate carboxylase in the recombinant microorganism is replaced with a strong promoter. By means of the specific optimization of the promoter of the gene encoding phosphoenolpyruvate carboxylase and the mutation of the encoding region of the gene, the ability of the strain to synthesize threonine is significantly improved.

A method for producing 2,4-dihydroxybutyrate (DHB) or L-threonine using a microbial metabolic pathway is disclosed, by expressing the metabolic pathway in a microbial production strain which was previously modified with respect to its natural wild type form by introducing at least one of the genes necessary for the expression of those enzymes used for the enzymatic conversions into the production strain.

The present invention concerns a metabolically engineered microorganism for glycine bioproduction or a salt or an ester thereof, the genome of said microorganism comprises an attenuation of the expression of genes encoding enzymes having glycine cleavage system activity as defined by E.C. 1.4.1.27 together with an overexpressing of threonine dehydrogenase dependent pathway as defined by EC E.C. 1.1.1.103 and E.C. 2.3.1.29 and/or with a threonine aldolase dependent pathway as defined by E.C. 4.1.2.48 or EC 4.1.2.42 or any of its catalytically active variants, its use for the production of glycine or one of its salts or esters. The present invention also concerns a fermentation process using said metabolically engineered microorganism for the production of glycine or one of its salts or esters.