The invention provides CadA polypeptides with mutations that increase activity in alkaline pH compared to the wild-type lysine decarboxylase. The invention also provides methods of generating such mutant polypeptides, microorganisms genetically modified to overexpress the mutant polypeptides, and methods of generating such microorganism.

The present invention relates to a method for producing a lysine carboxylase mutant strain, characteristics of the mutant strain, a gene encoding the lysine decarboxylase mutant strain, and a method for producing cadaverine using the same. The present invention provides lysine decarboxylase derived from E. coli improved through a protein engineering variation. In addition, the lysine decarboxylase mutant strain of the present invention increases activity, pH stability, and thermal stability at the time of producing cadaverine, thereby reducing production costs, through increasing a yield and productivity.

One aspect provided herein relates to lysine decarboxylase polypeptides comprising mutants of SEQ ID NO: 2 (i.e., mutants of Klebsiella oxytoca (K. oxytoca) Ldc) and/or fragments thereof. In certain embodiments, the mutants or fragments thereof may have at least about 95% sequence identity with SEQ ID NO: 2. Another aspect provided herein relates to a DNA polynucleotide comprising one or more lysine decarboxylase nucleotide sequences of mutants of SEQ ID NO: 1 (i.e., mutants of K. oxytoca ldc), fragments thereof, or fragments of SEQ ID NO: 1 (i.e., fragments of K. oxytoca ldc). In certain embodiments, the DNA polynucleotide as disclosed herein may encode one or more lysine decarboxylase polypeptides provided herein. In certain embodiments, the DNA polynucleotide as disclosed herein may encode SEQ ID NO: 2, mutants, and/or fragments thereof. In certain embodiments, the lysine decarboxylase nucleotide sequences provided herein may have at least 95% sequence identity with SEQ ID NO: 1 or SEQ ID NO: 3. Another aspect provided herein relates to expression vectors comprising the DNA polynucleotides described herein used for production of a lysine-derived product. Other aspects provided herein include transformants, mutant host cells, methods for the production of lysine decarboxylases, and methods for the production of a lysine-derived product.

Clostridium sp. are an obligate anaerobic bacterium that produces butyric acid as its major end-product. Previously, we have developed an integrated process that couples fermentation of biomass sugars, with in situ product recovery and distillation. This process works best at pH's lower than 7.0. The process serves to extract carboxylic acids during fermentation which enables reduced base-loading and reduced end-product toxicity. Disclosed herein are methods and non-naturally Clostridium sp. that are capable of increased production of butyric acid and increased growth at low pH conditions (e.g., pH<5.0).

The expression plasmid vectors comprise a polynucleotide sequence encoding Ldc2 polypeptide, a fragment, and/or a mutant. A backbone plasmid is capable of autonomous replication in a host cell. The host cell is not a P. aeruginosa cell. Transformants are transformed with expression plasmid vector. The transformants are not P. aeruginosa. Mutant host cells comprise a polynucleotide sequence encoding Ldc2 polypeptide, a fragment and/or a mutant that has been integrated into the host cell chromosome. A polypeptide, a fragment and/or a mutant comprise Ldc2. A non-naturally occurring polynucleotide, and/or a mutant encodes polypeptide comprising Ldc2. Biobased cadaverine is produced using the transformants and the biobased cadaverine is prepared by the method. Polyamides are formed using the biobased cadaverine and compositions.

Provided are a lysine decarboxylase immobilized cell and preparation method thereof.

Provided herein is a genetically modified host cell comprising a heterologous nucleic acid encoding a biofilm dispersal polypeptide that decreases intracellular c-di-GMP levels and enhances the production of lysine and lysine derivatives. Further provided are methods of generating such cell and producing lysine and lysine derivatives using the genetically modified host cell.

Provided are lysine decarboxylase polypeptides comprising mutants of SEQ ID NO: 2 and/or fragments thereof. The mutants or fragments have at least 95% sequence identity with SEQ ID NO: 2. Also provided are DNA polynucleotides encoding said lysine decarboxylases, expression vector comprising the DNA polynucleotides, transformants, mutant host cells, methods for the production of lysine decarboxylases, and methods for the production of a lysine-derived product.

Provided are microorganisms genetically modified to overexpress porin polypeptides to enhance the production of lysine and lysine derivatives by the microorganism. Also provided are methods of generating such microorganism, and methods of producing lysine and lysine derivatives using the genetically modified microorganisms.

The invention provides CadA polypeptides with mutations that increase activity in alkaline pH compared to the wild-type lysine decarboxylase. The invention also provides methods of generating such mutant polypeptides, microorganisms genetically modified to overexpress the mutant polypeptides, and methods of generating such microorganisms.