Recombinant host cells comprising phosphoketalase
View Patent ↗The present invention is related to recombinant host cells comprising: (i) at least one deletion, mutation, and/or substitution in an endogenous gene encoding a polypeptide that converts pyruvate to acetaldehyde, acetyl-phosphate or acetyl-CoA; and (ii) a heterologous polynucleotide encoding a polypeptide having phosphoketolase activity. The present invention is also related to recombinant host cells further comprising (iii) a heterologous polynucleotide encoding a polypeptide having phosphotransacetylase activity.
1. A method for the production of isobutanol comprising growing a recombinant host cell comprising:
(i) at least one genetic modification in an endogenous gene encoding a polypeptide having pyruvate decarboxylase activity, wherein the at least one genetic modification reduces or eliminates pyruvate decarboxylase activity;
(ii) a heterologous polynucleotide encoding a polypeptide having phosphoketolase activity, wherein the heterologous polynucleotide encoding a polypeptide having phosphoketolase activity is xpk1 from Lactobacillus plantarum , xpkA from Lactobacillus pentosus MD363, or 6-phosphate phosphoketolase from B. lactis;
(iii) at least one genetic modification in an endogenous gene encoding a polypeptide having glycerol-3-phosphate dehydrogenase activity, wherein the at least one genetic modification reduces or eliminates glycerol-3-phosphate dehydrogenase activity; and
(iv) an isobutanol biosynthetic pathway comprising the substrate to product conversions:
(a) pyruvate to acetolactate,
(b) acetolactate to 2,3-dihydroxyisovalerate,
(c) 2,3-dihydroxyisovalerate to 2-ketoisovalerate,
(d) 2-ketoisovalerate to isobutyraldehyde,
(e) isobutyraldehyde to isobutanol;
under conditions wherein isobutanol is produced and optionally recovering isobutanol.
2. The method of claim 1 , wherein the isobutanol is recovered by distillation, azeotropic distillation, liquid-liquid extraction, adsorption, gas stripping, membrane evaporation, pervaporation, vacuum flash, or combinations thereof.
3. The method of claim 1 , wherein the isobutanol is recovered by contacting the fermentation broth with an extractant.
4. The method of claim 3 , wherein the extractant is C 12 to C 22 fatty alcohols, C 12 to C 22 fatty acids, esters of C 12 to C 22 fatty acids, C 12 to C 22 fatty aldehydes, or mixtures thereof.
5. The recombinant host cell of claim 1 , wherein the polypeptide having phosphoketolase activity comprises at least 85% identity to SEQ ID NO: 481.
6. The recombinant host cell of claim 1 , wherein the recombinant host cell is Saccharomyces cerevisiae.