The present invention is related to a method for the production of a dicarboxylic acid, wherein the method comprises a bioconversion step, wherein in the bioconversion step, the dicarboxylic acid is produced from a precursor compound contained in a medium; and a purification step for purifying the dicarboxylic acid from the medium, wherein the purification step comprises (a) a nano-diafiltration step and/or (b) a distillation step or an evaporation step or both a distillation step and an evaporation step, wherein preferably if the purification step comprises (a) the nano-diafiltration step and (b) the distillation step or the evaporation step or both the distillation step and the evaporation step, the nano-diafiltration step is carried out prior to the distillation step and the evaporation step, respectively, and
wherein the dicarboxylic acid is selected from the group comprising decanedioic acid, dodecanedioic acid, tetradecanedioic acid and hexadecanedioic acid, preferably the dicarboxylic acid is dodecanedioic acid (DDDA).

The present invention is related to a method for the production of a dicarboxylic acid, wherein the method comprises a bioconversion step, wherein in the bioconversion step, the dicarboxylic acid is produced from a precursor compound contained in a medium; and a purification step for purifying the dicarboxylic acid from the medium, wherein the purification step comprises (a) a nano-diafiltration step and/or (b) a distillation step or an evaporation step or both a distillation step and an evaporation step, wherein preferably if the purification step comprises (a) the nano-diafiltration step and (b) the distillation step or the evaporation step or both the distillation step and the evaporation step, the nano-diafiltration step is carried out prior to the distillation step and the evaporation step, respectively, and
wherein the dicarboxylic acid is selected from the group comprising decanedioic acid, dodecanedioic acid, tetradecanedioic acid and hexadecanedioic acid, preferably the dicarboxylic acid is dodecanedioic acid (DDDA).

The present disclosure provides a system for extracting long chain dicarboxylic acid, the system comprising: a primary membrane filtration unit, a first crystallization unit, a first separation unit, a first dissolution tank, a secondary membrane filtration unit, a second separation unit, a second crystallization unit and a third separation unit. By the system for extracting long chain dicarboxylic acid of an embodiment of the present invention, the resulted long chain dicarboxylic acid product has a high purity, very low and even no residual alkane residue, and organic solvent-free.

The present disclosure provides a method for extracting long chain dicarboxylic acid, the method comprising: (1) subjecting a long chain dicarboxylic acid fermentation broth to a primary membrane filtration treatment to give a first filtrate; subjecting the first filtrate to decolorization, crystallization, and solid-liquid separation to give a first solid; (2) redissolving the first solid in water to form a solution; subjecting the solution to decolorization, crystallization by acidification, and solid-liquid separation to give a second solid. By the method, the resulted long chain dicarboxylic acid product has a high purity and no residual organic solvent.

The present disclosure provides a method for extracting long chain dicarboxylic acid, the method comprising: (1) subjecting a long chain dicarboxylic acid fermentation broth to a primary membrane filtration treatment to give a first filtrate; subjecting the first filtrate to decolorization, crystallization, and solid-liquid separation to give a first solid; (2) redissolving the first solid in water to form a solution; subjecting the solution to decolorization, crystallization by acidification, and solid-liquid separation to give a second solid. By the method, the resulted long chain dicarboxylic acid product has a high purity and no residual organic solvent.

The present disclosure provides a system for refining long chain dicarboxylic acid, comprising: a first membrane filtration unit, for a first membrane filtration of a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom; a first decolorization unit, for carrying out a first decolorization treatment to the filtrate obtained after the membrane filtration; a first acidification/crystallization unit, for carrying out a first acidification/crystallization of a filtrate obtained after the membrane filtration to give a solid-liquid mixture; a first separation unit, for a solid-liquid separation of the solid-liquid mixture; a drying unit, for drying the solid separated by the separation unit to give a first solid. By using the refining system according to the present disclosure, the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

The present disclosure provides a system for refining long chain dicarboxylic acid, comprising: a first membrane filtration unit, for a first membrane filtration of a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom; a first decolorization unit, for carrying out a first decolorization treatment to the filtrate obtained after the membrane filtration; a first acidification/crystallization unit, for carrying out a first acidification/crystallization of a filtrate obtained after the membrane filtration to give a solid-liquid mixture; a first separation unit, for a solid-liquid separation of the solid-liquid mixture; a drying unit, for drying the solid separated by the separation unit to give a first solid. By using the refining system according to the present disclosure, the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

The present disclosure provides a method and a system for refining long chain dicarboxylic acid, said method comprising the following steps: (1) subjecting a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom to a membrane filtration, an acidification/crystallization, a solid-liquid separation and drying to give a long chain dicarboxylic acid crude product; (2) subjecting the long chain dicarboxylic acid crude product to a vacuum distillation to give the long chain dicarboxylic acid product; wherein the pressure in the vacuum distillation is ≤100 Pa. By using the refining method according to the present disclosure, the procedure is simplified, and the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

The present disclosure provides a method and a system for refining long chain dicarboxylic acid, said method comprising the following steps: (1) subjecting a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom to a membrane filtration, an acidification/crystallization, a solid-liquid separation and drying to give a long chain dicarboxylic acid crude product; (2) subjecting the long chain dicarboxylic acid crude product to a vacuum distillation to give the long chain dicarboxylic acid product; wherein the pressure in the vacuum distillation is ≤100 Pa. By using the refining method according to the present disclosure, the procedure is simplified, and the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

The present disclosure provides a method and a system for refining long chain dicarboxylic acid, said method comprising the following steps: (1) subjecting a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom to a membrane filtration, an acidification/crystallization, a solid-liquid separation and drying to give a long chain dicarboxylic acid crude product; (2) subjecting the long chain dicarboxylic acid crude product to a vacuum distillation to give the long chain dicarboxylic acid product; wherein the pressure in the vacuum distillation is ≤100 Pa. By using the refining method according to the present disclosure, the procedure is simplified, and the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.