Producing dicarboxylic acids using polyketide synthases
The present invention provides for a polyketide synthase (PKS) capable of synthesizing a dicarboxylic acid (diacid). Such diacids include diketide-diacids and triketide-diacids. The invention includes recombinant nucleic acid encoding the PKS, and host cells comprising the PKS. The invention also includes methods for producing the diacids.
1. A method of producing a diacid, comprising culturing a prokaryotic or yeast host cell comprising a recombinant nucleic acid that encodes a polyketide synthase (PKS), said PKS composed of a loading module containing a beta-keto acyl carrier protein synthase Q domain (KS Q ) lacking decarboxylase activity, one or more extender modules, and a thioesterase (TE) domain, in a suitable culture medium such that the diacid is produced.
2. The method of claim 1 , further comprising: (c) isolating said diacid from the host cell and the culture medium.
3. The method of claim 2 , further comprising: (d) reacting the diacid with a diamine to produce a nylon.
4. The method of claim 2 , further comprising: (d) reacting the diacid with a dialcohol to produce a polyester.
5. The method of claim 1 , wherein said diacid is pentane-1,5-dioic acid, and said PKS has a loading module that utilizes malonate and a single extender module that has a malonate-specific acyltransferase (AT) domain and a full set of reduction domains.
6. The method of claim 1 , wherein said diacid is heptane-1,7-dioic acid, and said PKS has a loading module that utilizes malonate and two extender modules, each of which has a malonate-specific acyltransferase (AT) domain and a full set of reduction domains.
7. The method of claim 1 , wherein the host cell is a prokaryotic host cell.
8. The method of claim 7 , wherein the host cell is an E. coli or a Streptomyces sp . cell.
9. the method of claim 8 , wherein the PKS comprises the loading module and module 1 of the spiramycin, oligomycin, or primaricin PKS and the TE domain from erythromycin PKS or the TE domain encoded by the monCII gene, wherein the KS Q domain of the loading module is deleted or modified to inactivate the decarboxylase activity.
10. The method of claim 5 , wherein the loading module is from spiromycin, and the extender module is module 5 or module 6 from nystatin PKS or module 3from the oligomycin PKS, and the TE domain is from erythromycin PKS.
11. The method of claim 10 , wherein the host cell is an E. coli or a Streptomyces sp . cell.
12. The method of claim 6 , wherein the loading module is from spiromycin, the first extender module is module 5 or module 6 from nystatin PKS or module 3from the oligomycin PKS, the second extender module is module 5 from the epothilone PKS, and the TE domain is from erythromycin PKS.
13. The method of claim 11 , wherein the host cell is an E. coli or a Streptomyces sp . cell.