Classifications

• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P41/00—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture
  • C12P41/003—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture by ester formation, lactone formation or the inverse reactions
  • C12P41/005—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture by ester formation, lactone formation or the inverse reactions by esterification of carboxylic acid groups in the enantiomers or the inverse reaction
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P41/00—Processes using enzymes or microorganisms to separate optical isomers from a racemic mixture
• • C—CHEMISTRY; METALLURGY
  • C12—BIOCHEMISTRY; BEER; SPIRITS; WINE; VINEGAR; MICROBIOLOGY; ENZYMOLOGY; MUTATION OR GENETIC ENGINEERING
  • C12P—FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE
  • C12P13/00—Preparation of nitrogen-containing organic compounds
  • C12P13/04—Alpha- or beta- amino acids

Definitions

• the invention relates to a process for the preparation of an amino acid enriched in the D-enantiomer, in which a mixture of the enantiomers of the corresponding N-carbamoylamino acid is brought into contact with a D-carbamoylase with ammonia being liberated.
• D-amino acids are important building blocks for biologically active preparations such as ⁇ -lactam antibiotics, peptide hormones and pesticides.
• a commonly used preparation process for these "unnatural" amino acids is a process in which the corresponding DL-5-substituted hydantoin is enantioselectively hydrolysed by a hydantoinase to form the corresponding N-carbamoylamino acid. This N- carbamoylamino acid can be converted enzymatically to the corresponding D-amino acid.
• a disadvantage of the known process is that, to realise a certain reaction time, relatively large quantities of biocatalyst are necessary because it is generally known that the enzyme that is responsible for the hydrolysis of carbamoylamino acids (the carbamoylase, also called N-carbamoyl-D-amino acid amidohydrolase) is strongly inhibited by the reaction product ammonia.
• carbamoylase also called N-carbamoyl-D-amino acid amidohydrolase
• the concentration at which ammonia-caused inhibition occurs is reported (Olivieri et. al. (1981) Biotechnology and Bioengineering, vol.
• the ammonia formed is removed by distillation.
• this process for the removal of ammonia is effective only when the reaction mixture has a high pH.
• the carbamoylase enzyme is not active.
• ammonia is removed by distillation at neutral pH, between pH 7-7.5, 60 to 90% of the formed ammonia remains in the reaction mixture even when more than 90% of the reaction volume is removed. Therefore, efficient removal at neutral pH is not possible.
• the invention now provides a simple and economically attractive process in which less biocatalyst needs to be used or a shorter reaction time is realised.
• This is achieved according to the invention by removing the ammonia with the aid of a bivalent metal salt of a phosphate ion, a monohydrogen phosphate ion or a dihydrogen phosphate ion; in the further description briefly designated as phosphate salt.
• a bivalent metal salt of a phosphate ion, a monohydrogen phosphate ion or a dihydrogen phosphate ion in the further description briefly designated as phosphate salt.
• the enzymatic reaction can be carried out (for example) in the presence of a phosphate salt.
• the reaction mixture remained easily stirrable also at high slurry concentrations.
• Another embodiment is formed for example by leading the reaction mixture via for example a loop after separation of the undissolved reaction components, through for example a second reactor, or a column or a filter in which the phosphate salt is present.
• the ammonia present in the reaction mixture is then bound to the phosphate salt, yielding the corresponding ammonium phosphate salt, after which the remaining liquid, which still contains for example enzyme, is returned to the enzymatic decarbamoylation reaction vessel. It has been found that no or much less enzyme inhibition takes place. This is all the more surprising because it is known that divalent metals can interfere with carbamoylase-catalysed reactions even at low concentrations (1 -10 ⁇ molar).
• Suitable bivalent metal ions are magnesium, cobalt, calcium, manganese, zirconium or ruthenium ions.
• magnesium monohydrogen phosphate MgHPO 4
• MgHPO 4 fits in with the optimum process conditions as regards the resulting pH and is easy to prepare from cheap raw materials.
• the phosphate salt can also be formed in situ.
• the phosphate salt for example MgHPO 4
• MgHPO 4 can be prepared in a simple way by addition of phosphoric acid to the corresponding oxide or hydroxide, for example magnesium oxide or hydroxide, which yields phosphate salt.
• the phosphate salt obtained can subsequently be added (optionally after filtering and washing).
• the quantity of phosphate salt to be used preferably lies between 0.5 and 3 phosphate salt equivalents, in particular between 0.8 and 1.2 equivalents, related to the quantity of ammonia that is formed during the reaction.
• suitable enzymes are the enzymes that are usually used in hydantoinase-carbamoylase processes, for example enzymes derived from the genus Pseudomonas, in particular Pseudomonas fluorescens, putida or desmolytica, Achromobacter, Corynebacterium, Bacillus, in particular Bacillus brevis or Bacillus stearothermophilus, Brevibacterium, Microbacterium, Artrobacter, Agrobacterium, in particular Agrobacterium tumefaciens or radiobacter, Acrobacter, Klebsiella, Sarcina, Protaminobacter, Streptomyces, Actinomyces, Candida, Rhodotorula, Pichia or Paecilomyces.
• Pseudomonas in particular Pseudomonas fluorescens, putida or desmolytica
• Achromobacter Corynebacterium
• the enzymatic reaction can be carried out at a pH that lies between pH 5 and pH 9 and is preferably carried out at a pH that lies between pH 6 and 8.
• the temperature at which the enzymatic reaction is carried out preferably lies between 0 and 50°C, in particular between 20 and 40°C.
• a suitable recovery for example takes place by acidifying the reaction mixture to a pH between 0 and 3, preferably between 0.5 and 1.5, followed by removal of the biomass.
• the D-amino acid can be separated, for example by filtration or centrifugation.
• the corresponding ammonium phosphate salt formed from the phosphate salt can be separated for example via centrifugation or filtration.
• Another suitable recovery takes place for example by increasing the pH to a value between 9 and 11, preferably between 9.5 and 10.5, after which the corresponding solid ammonium phosphate salt formed from phosphate salt can be filtered off.
• the biomass is subsequently removed, for example by means of microfiltration or ultrafiltration.
• solid D- amino acid can subsequently be isolated, for example by means of filtration.
• the resulting ammonium phosphate salt can subsequently simply be converted in a known way into the phosphate salt by dry heating of the ammonium phosphate salt, with ammonia being liberated.
• Another method is to heat a slurry of the ammonium phosphate salt at a pH > 8.5, in particular between 9 and 11 , with ammonia being liberated.
• Yet another method is to wash the magnesium ammonium phosphate salt with a mineral acid, for instance sulphuric acid, keeping the pH between 4.5 and 6.5, preferably between 5.5 and 6. Accordingly the salt of ammonium and the mineral acid is obtained and Mg hydrophosphate can be recovered.
• the invention is particularly suitable for use in the preparation of enantiomerically enriched amino acids via the so-called hydantoin route, which involves the preparation of N-carbamoylamino acid enriched in the D-enantiomer from the corresponding hydantoin with the aid of a hydantoinase, optionally in combination with a racemase, followed by the decarbamoylation with the aid of D- carbamoylase, wherein the decarbamoylation is the overall reaction rate determining step.
• hydantoin route involves the preparation of N-carbamoylamino acid enriched in the D-enantiomer from the corresponding hydantoin with the aid of a hydantoinase, optionally in combination with a racemase, followed by the decarbamoylation with the aid of D- carbamoylase, wherein the decarbamoylation is the overall reaction rate determining step.
• the process according to the invention can also be used in resolution processes in which a DL-N-carbamoylamino acid is converted to the corresponding amino acid enriched in the D-enantiomer and the non- converted L- N-carbamoylamino acid enriched in the enantiomer with the aid of a microorganism that contains a D-selective hydantoin-hydrolysing and a N-carbamoyl- amino acid-hydrolysing enzyme.
• the reaction can be carried out at an elevated pH (for example between 7.5 and 9), there is less loss of L-N carbamoylamino acid, for at elevated pH the hydantoinase reaction does not proceed.
• a hydrolysis of DL-p-hydroxyphenylglycine hydantoin was carried out by adding 122 g of this compound with 122 g MgHPO 4 -3H 2 O to 575 ml water.
• the enzymatic conversion was started by addition of 8 ml Agrobacterium radiobacter cell suspension.
• the MgNH 4 PO 4 was washed twice with 50 ml water after which it was suspended in water. Next, a mixture of water and ammonia was evaporated under reduced pressure.
• the reaction mixture was filtered after which the residue was washed twice with 100 ml water.
• the filtrate of this step was led through a microfiltration set-up to remove any cell residues.
• the retentate was washed a few times.
• the permeate was then acidified with around 40 g H 2 SO 4 to a pH of 3.5, upon which D-p-hydroxyphenylglycine crystallises. After separating, washing and drying a yield of 102 g D-p- hydroxyphenylglycine was obtained.
• Example VIII 15 g DL-valine hydantoin and 20 g MgHPO 4 -3H 2 O was added to

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• 2001
  • 2001-01-31 NL NL1017250A patent/NL1017250C1/nl not_active IP Right Cessation
• 2002
  • 2002-01-31 CN CNA028044282A patent/CN1520460A/zh active Pending
  • 2002-01-31 WO PCT/NL2002/000072 patent/WO2002061107A2/en not_active Application Discontinuation
  • 2002-01-31 AU AU2002230274A patent/AU2002230274A1/en not_active Abandoned
  • 2002-01-31 KR KR10-2003-7009948A patent/KR20030071868A/ko not_active Application Discontinuation
  • 2002-01-31 HU HU0302864A patent/HUP0302864A2/hu unknown
  • 2002-01-31 EP EP02711530A patent/EP1404854A2/en not_active Withdrawn
  • 2002-01-31 JP JP2002561661A patent/JP2004521623A/ja not_active Withdrawn
  • 2002-01-31 CZ CZ20032077A patent/CZ20032077A3/cs unknown

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