Fermentative production of acetone from renewable resources by means of novel metabolic pathway
The invention describes a process for preparing acetone starting from acetyl-coenzyme A comprising process steps A. enzymatic conversion of acetyl-CoA into acetoacetyl-CoA B. enzymatic conversion of acetoacetyl-CoA into acetoacetate and CoA and C. decarboxylation of acetoacetate to acetone and CO 2 , which is characterized in that the coenzyme A is not transferred in process step B to an acceptor molecule. In addition, process step B is surprisingly catalyzed by enzymes of the classes of acyl-CoA thioesterase, acyl-CoA synthetase or acyl-CoA thiokinase. A completely novel metabolic pathway is concerned, because the enzymatic hydrolysis of acetoacetyl-CoA without simultaneous transfer of CoA to a receptor molecule has never previously been described for any microbial enzyme.
1. A process for preparing acetone starting from acetyl-coenzyme A, comprising:
A. contacting acetyl-CoA with a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 16 and which converts acetyl CoA into acetoacetyl CoA;
B. contacting the acetoacetyl-CoA with a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 1, 3 or 5 and which converts acetoacetyl CoA into acetoacetate and CoA; and
C. contacting the acetoacetate with a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 18 and which decarboxylates the acetoacetate to produce acetone and CO 2 ;
wherein the coenzyme A in B is not transferred to an acceptor molecule.
2. The process of claim 1 , comprising:
A. contacting acetyl-CoA with a polypeptide that is at least 95% identical to the amino acid sequence of SEQ ID NO: 16 and which converts acetyl CoA into acetoacetyl CoA;
B. contacting the acetoacetyl-CoA with a polypeptide that is at least 95% identical to the amino acid sequence of SEQ ID NO: 1, 3 or 5 and which converts acetoacetyl CoA into acetoacetate and CoA; and
C. contacting the acetoacetate with a polypeptide that is at least 95% identical to the amino acid sequence of SEQ ID NO: 18 and which decarboxylates the acetoacetate to acetone and CO 2 ;
wherein the coenzyme A in B is not transferred to an acceptor molecule.
3. The method of claim 1 , wherein B comprises contacting the acetoacetyl-CoA with a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 1 to produce acetoacetate.
4. The method of claim 1 , wherein B comprises contacting the acetoacetyl-CoA with a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 3 to produce acetoacetate.
5. The method of claim 1 , wherein B comprises contacting the acetoacetyl-CoA with a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 5 to produce acetoacetate.
6. The process according to claim 1 that is carried out by a microorganism.
7. The process according to claim 6 , wherein the microorganism comprises
a polynucleotide encoding a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 16;
a polynucleotide encoding a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 1, 3 or 5; and
a polynucleotide encoding a polypeptide that is at least 90% identical to the amino acid sequence of SEQ ID NO: 18.
8. The process of claim 1 , comprising:
A. contacting acetyl-CoA with a polypeptide that is at least 98% identical to the amino acid sequence of SEQ ID NO: 16 and which converts acetyl CoA into acetoacetyl CoA;
B. contacting the acetoacetyl-CoA with a polypeptide that is at least 98% identical to the amino acid sequence of SEQ ID NO: 1, 3 or 5 and which converts acetoacetyl CoA into acetoacetate and CoA; and
C. contacting the acetoacetate with a polypeptide that is at least 98% identical to the amino acid sequence of SEQ ID NO: 18 and which decarboxylates the acetoacetate to acetone and CO 2 ;
wherein the coenzyme A in B is not transferred to an acceptor molecule.
9. The process of claim 1 , comprising:
A. contacting acetyl-CoA with a polypeptide that is at least 99% identical to the amino acid sequence of SEQ ID NO: 16 and which converts acetyl CoA into acetoacetyl CoA;
B. contacting the acetoacetyl-CoA with a polypeptide that is at least 99% identical to the amino acid sequence of SEQ ID NO: 1, 3 or 5 and which converts acetoacetyl CoA into acetoacetate and CoA; and
C. contacting the acetoacetate with a polypeptide that is at least 99% identical to the amino acid sequence of SEQ ID NO: 18 and which decarboxylates the acetoacetate to acetone and CO 2 ;
wherein the coenzyme A in B is not transferred to an acceptor molecule.
10. The process of claim 1 , comprising:
A. contacting acetyl-CoA with a polypeptide having the amino acid sequence of SEQ ID NO: 16 and which converts acetyl CoA into acetoacetyl CoA;
B. contacting the acetoacetyl-CoA with a polypeptide having the amino acid sequence of SEQ ID NO: 1, 3 or 5 and which converts acetoacetyl CoA into acetoacetate and CoA; and
C. contacting the acetoacetate with a polypeptide that is at least 99% identical to the amino acid sequence of SEQ ID NO: 18 and which decarboxylates the acetoacetate to acetone and CO 2 ;
wherein the coenzyme A in B is not transferred to an acceptor molecule.