The present disclosure describes the engineering of microbial cells for fermentative production of tyramine and provides novel engineered microbial cells and cultures, as well as related tyramine production methods.

The disclosure discloses recombinant Pseudomonas plecoglossicida for producing L-xylose and application thereof, and belongs to the technical field of bioengineering. According to the disclosure, a synthesized 2-ketogluconate reductase gene and a 2,5-diketogluconate reductase gene derived from Corynebaterium ATCC 31090 and a pyruvate decarboxylase gene derived from Saccharomyces cerevisiae are successfully expressed in a host P. plecoglossicida by a double plasmid system, and an obtained genetically engineered strain is fermented for 56 h in a shake flask, where the yield of L-xylose reaches 16.2 g/L, and the transformation rate reaches 20.3%; the obtained genetically engineered strain is fermented for 48 h and 44 h in 3 L and 15 L fermentors, respectively, where the yields of L-xylose reach 37.6 g/L and 45.8 g/L, respectively, and the glucose transformation rates are 47.0% and 57.3%, respectively. The method has the advantages of low raw material cost, no pollution to the environment, simple operation, and important economic and social benefits.

A method for constructing an ALA production bacterial strain, the method enhances the activity of related enzymes promoting the synthesis of oxaloacetate and in the 5-aminolevulinic acid (ALA) production bacterial strain, or introducing exogenous related enzymes promoting the synthesis of oxaloacetate, such as phosphoenolpyruvate carboxylase or pyruvate carboxylase, and/or reducing the activity of related enzymes in the downstream metabolic pathway of succinyl coenzyme A in the bacterial strain, such as succinyl coenzyme A synthetase or succinate dehydrogenase, and/or reducing the activity of phosphoenolpyruvate carboxylated kinase and/or malic enzyme. An ALA high-yield bacterial strain constructed by utilizing the method, and method for utilizing the bacterial strain to prepare ALA.

The present invention relates to a novel variant RNA polymerase sigma factor 70 (σ.sup.70) polypeptide, a polynucleotide encoding the same, a microorganism containing the polypeptide, and a method for producing L-threonine by using the microorganism.

The present disclosure relates to a microorganism producing L-tryptophan in which the microorganism is modified such that a protein having an L-tryptophan-exporting activity comprising the amino acid sequence of SEQ ID NO: 1 is expressed, and a method for producing L-tryptophan using the microorganism.

The present disclosure relates to modified homoserine dehydrogenase and a method for producing homoserine or a homoserine-derived L-amino acid using the same.

The invention provides a method for producing a terpene or a precursor thereof by microbial fermentation. Typically, the method involves culturing a recombinant bacterium in the presence of a gaseous substrate whereby the bacterium produces a terpene or a precursor thereof, such as mevalonic acid, isopentenyl pyrophosphate, dimethylallyl pyrophosphate, isoprene, geranyl pyrophosphate, farnesyl pyrophosphate, and/or farnesene. The bacterium may comprise one or more exogenous enzymes, such as enzymes in mevalonate, DXS, or terpene biosynthesis pathways.

Disclosed herein is a recombinant microorganism having enhanced 2,3-butanediol producing ability, wherein a pathway for converting pyruvate to acetyl-CoA, a pathway for converting pyruvate to formic acid, or a pathway for converting pyruvate to lactate is inhibited in a microorganism having acetyl-CoA and lactate biosynthetic pathways.

An enzyme has an activity of reversible dehydrogenation of D-amino acid and is a hexamer of polypeptides having an amino acid sequence that has 80% or more identity with the amino acid sequence of SEQ ID NO: 2. The amino acid sequence of the polypeptide can include one or more amino acid substitutions for one or more amino acid residues of SEQ ID NO: 2.

The present disclosure relates to a novel promoter and a method for producing L-amino acids using the promoter, and more specifically, to a novel polynucleotide having promoter activity, a vector and a microorganism of the genus Corynebacterium comprising the polynucleotide, a method for producing L-amino acids and a fermented composition using the microorganism, and a fermented composition.