Metabolic engineering of Escherichia coli for efficient biosynthesis of butyl acetate

Jason T Ku,Arvin Y Chen,Ethan I Lan

doi:10.1186/s12934-022-01755-y

Jason T Ku, Arvin Y Chen + Show 1 more

Open Access

https://doi.org/10.1186/s12934-022-01755-y

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Abstract

BackgroundButyl acetate is a versatile compound that is widely used in the chemical and food industry. The conventional butyl acetate synthesis via Fischer esterification of butanol and acetic acid using catalytic strong acids under high temperature is not environmentally benign. Alternative lipase-catalyzed ester formation requires a significant amount of organic solvent which also presents another environmental challenge. Therefore, a microbial cell factory capable of producing butyl acetate through fermentation of renewable resources would provide a greener approach to butyl acetate production.ResultHere, we developed a metabolically engineered strain of Escherichia coli that efficiently converts glucose to butyl acetate. A modified Clostridium CoA-dependent butanol production pathway was used to synthesize butanol which was then condensed with acetyl-CoA through an alcohol acetyltransferase. Optimization of alcohol acetyltransferase expression and redox balance with auto-inducible fermentative controlled gene expression led to an effective titer of 22.8 ± 1.8 g/L butyl acetate produced in a bench-top bioreactor.ConclusionBuilding on the well-developed Clostridium CoA-dependent butanol biosynthetic pathway, expression of an alcohol acetyltransferase converts the butanol produced into butyl acetate. The results from this study provided a strain of E. coli capable of directly producing butyl acetate from renewable resources at ambient conditions.

Highlights

Butyl acetate is an industrially important chemical used as a solvent for various coatings and paints involved in the production of consumer products such as automobiles, wood furniture, artificial leather, printing inks, nail polish and adhesives [1,2,3]
Building on the well-developed Clostridium CoA-dependent butanol biosynthetic pathway, expression of an alcohol acetyltransferase converts the butanol produced into butyl acetate
The results from this study provided a strain of E. coli capable of directly producing butyl acetate from renewable resources at ambient conditions

Summary

Introduction

Butyl acetate is an industrially important chemical used as a solvent for various coatings and paints involved in the production of consumer products such as automobiles, wood furniture, artificial leather, printing inks, nail polish and adhesives [1,2,3]. Butyl acetate is currently manufactured through Fischer esterification of butanol and acetic acid under elevated temperature with sulfuric acid for catalysis [7], which is not environmentally benign for the volume at which butyl acetate is produced. To address this difficulty, mild methods for preparing butyl acetate such as using lipase for catalysis have been developed. Lipase-catalyzed condensation requires a significant amount of organic solvent which presents another environmental challenge [8, 9]. The conventional butyl acetate synthesis via Fischer esterification of butanol and acetic acid using catalytic strong acids under high temperature is not environmentally benign. A microbial cell factory capable of producing butyl acetate through fermentation of renewable resources would provide a greener approach to butyl acetate production

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