Production of fusel lactates via biocatalysis
Microbial enzymes are used for esterification of biomass-derived substrates for production of industrially valuable esters. E. coli was used as an efficient platform for recombinant synthesis of fusel lactates such as the green solvent ethyl lactate.
1. A process for converting a glucose-containing hydrolyzed biomass into a fusel lactate, the process comprising:
expressing an esterase gene in a bacterial host, the bacterial host being added to or already present in the glucose-containing hydrolyzed biomass;
maintaining conditions suitable for fermenting in the hydrolyzed biomass, the fermenting producing an alcohol and a lactate; and
catalyzing through an enzyme encoded by the esterase gene, a reaction from the alcohol and lactate to form a fusel lactate in the bacterial host;
wherein the enzyme is selected from the group consisting of: ethyl-ester-synthase-1, acetylxylan-esterase-2, carbohydrate-esterase, esterase-A, truncated-esterase-A, and combinations thereof;
wherein the esterase gene is obtained from an organism selected from: Komagataella phaffii, Saccharomyces cerevisiae, Brettanomyces bruxellensis , or Pseudomonas aeruginosa.
2. The process of claim 1 , wherein the fusel lactate is selected from the group consisting of: ethyl lactate, isopentyl lactate, isopropyl lactate, (iso)butyl lactate, and (iso)pentyl lactate.
3. The process of claim 1 , wherein the bacterial host produces a fermentation strain that produces alcohol.
4. The process of claim 1 , wherein the reaction is further catalyzed by organic acids, Coenzyme A, adducts thereof, or combinations thereof also present in the hydrolyzed biomass.
5. The process of claim 1 , wherein the esterase gene is selected from EEB1, CE, tEstA, and EstA or combinations thereof.
6. The process of claim 1 , wherein the maintaining conditions suitable for fermenting include maintaining a pH of 6 to 8, and a temperature of 22 to 37° C.
7. The process of claim 1 , wherein the bacterial host is cloned with esterase enzymes using a pET15b plasmid at an NdeI/BamHI locus of the bacterial host.
8. The process of claim 1 , further comprising separating the fusel lactate from a remainder of the hydrolyzed biomass by extracting it and distilling it from the hydrolyzed biomass.
9. The process of claim 1 , wherein the bacterial host is Corynebacterium glutamicum.
10. The process of claim 1 , wherein the enzyme has a k m for producing ethyl lactate;
and the k m is less than 30.2×10 −6 M.
11. A process for converting a glucose-containing hydrolyzed biomass into a fusel lactate, the process comprising:
expressing an esterase gene in a bacterial host, the bacterial host being added to or already present in the glucose-containing hydrolyzed biomass;
maintaining conditions suitable for fermenting in the hydrolyzed biomass, the fermenting producing an alcohol and a lactate; and
catalyzing through an enzyme encoded by the esterase gene, a reaction from the alcohol and lactate to form a fusel lactate in the bacterial host;
wherein the esterase gene is selected from EEB1, CE, tEstA, and EstA or combinations thereof;
wherein the enzyme has a k m and a v max for producing ethyl lactate, and the k m is less than 30.2×10 −6 M and the v max is from 1.5×10 −6 mol/(L*s) to 2×10 −6 mol/(L*s).
12. The process of claim 11 , wherein the bacterial host is cloned with esterase enzymes using a pET15b plasmid at an NdeI/BamHI locus of the bacterial host.
13. The process of claim 12 , wherein the esterase gene is selected from EEB1, CE, tEstA, and EstA or combinations thereof.
14. The process of claim 1 , wherein the bacterial host is E. Coli.
15. The process of claim 11 , wherein the esterase gene is obtained from an organism selected from: Komagataella phaffii, Brettanomyces bruxellensis , or Pseudomonas aeruginosa.
16. A process for converting a glucose-containing hydrolyzed biomass into a fusel lactate, the process comprising:
expressing an acyl-alcohol transferase gene, esterase gene, or both in a bacterial host, the bacterial host being added to or already present in the glucose-containing hydrolyzed biomass;
maintaining conditions suitable for fermenting in the hydrolyzed biomass, the fermenting producing an alcohol and a lactate; and
catalyzing through an enzyme encoded by the acyl-alcohol transferase gene or -esterase gene, a reaction from the alcohol and lactate to form a fusel lactate in the bacterial host;
wherein the enzyme is selected from the group consisting of: ethyl-ester-synthase-1, acetylxylan-esterase-2, carbohydrate-esterase, esterase-A, truncated-esterase-A, diacylglycerol-transferase, ethanol-o-acyltransferase, propionate CoA transferase, and combinations thereof;
wherein the acyl-alcohol transferase gene or esterase gene are obtained from an organism selected from: Komagataella phaffii, Saccharomyces cerevisiae, Brettanomyces bruxellensis , or Pseudomonas aeruginosa.
17. The process of claim 11 , wherein the fusel lactate is ethyl lactate, and the the esterase gene is selected from EEB1 and CE.
18. The process of claim 16 , wherein the bacterial host is cloned with esterase enzymes using a pET15b plasmid at an NdeI/BamHI locus of the bacterial host.
19. The process of claim 16 , wherein the enzyme has a k m for producing ethyl lactate and the k m is less than 30.2×10 −6 M.
20. The process of claim 16 , wherein the enzyme is selected from the group consisting of: diacylglycerol-transferase, ethanol-o-acyltransferase, propionate CoA transferase, and combinations thereof.