Table 2.

Overview of metabolic engineering for microbial ester production

Enzyme source	Production host	Ester products	Titer	Genetic manipulations	References
S. cerevisiae (ATF1)	Clostridium autoethanogenum	Ethyl acetate	0.3 mM	Using CO-based feedstocks for microbial ester production	[104]
		Butyl acetate	4.5 mM
F. ananassa (AAT)	S. cerevisiae	Ethyl crotonate	125.59 ± 2.04 mg/L	The expression cassettes with different strengths to regulate the expression of key genes	[91]
S. cerevisiae (ATF1)	E. coli	Neryl acetate	11.712 ± 0.653 mg/L	Overexpression of tHMG1 and supplementation with 2 g/L pyruvate	[105]
S. cerevisiae (ATF1)	E. coli	Isobutyl acetate	2.48 g/L	Removing byproduct pathways (Δldh, ΔpoxB, Δpta) and overexpressing AAT	[82]
S. cerevisiae (ATF1)	E. coli	Isoamyl acetate	0.78 g/L
Staphylococcus aureus (CAT)	E. coli	Isoamyl acetate	8.8 g/L	A systematic modular design approach to control proteome reallocation for the selective microbial biosynthesis of branched-chain acetate esters via manipulation of substrate specificity and expression level of multiple pathway enzymes	[79]
S. cerevisiae (ATF1)	Pseudomonas putida KT2440	Hexyl acetate	160.5 mg/L	Overexpression of transporters	[106]
V. cerevisiae (ATF1)	E. coli	Indole-3-ethanol acetate	550 ± 24.05 mg/L	Biosynthesis of indole-3-ethanol acetate directly from a renewable carbon source	[89]
S. cerevisiae (ATF2)	industrial yellow rice wine yeast strain	Ethyl acetate	137.79 mg/L	Overexpressing the alcohol acetyltransferase-encoding gene ATF2	[107]
		Isoamyl acetate	26.68 mg/L
		Isobutyl acetate	7.60 mg/L
Wickerhamomyces anomalus (EAT1)	S. cerevisiae	Ethyl acetate	6.48 ± 0.32 g/L	A novel alcohol acetyltransferase family	[42]
S. cerevisiae (ATF1)	E. coli	Isobutyl acetate	17.2 g/L	Engineered E. coli has an ability to produce acetate ester, isobutyrate ester, butyrate ester	[7]
		Tetradecyl acetate	137 mg/L
Strawberry (AAT)	S. cerevisiae	Ethyl hexanoate	42.35 ± 1.75 mg/L	Optimizing the synthetic pathway of ethyl hexanoate	[108]
S. cerevisiae (ATF1)	E. coli	Farnesyl acetate	128 ± 10.5 mg/L	Biosynthesis of the advanced biofuel farnesyl acetate directly from glucose	[109]
		Farnesyl acetate	201 ± 11.7 mg/L
Strawberry (AAT)	S. cerevisiae	Ethyl butyrate	99.65 ± 7.32 mg/L	Introduced a butyryl-CoA synthesis pathway into S. cerevisiae	[110]
Kiwifruit (AeAT9)	S. cerevisiae	Ethyl acetate	1.69 g/L	Impeded mitochondrial transport and utilization of pyruvate and acetyl-CoA to increase the ethyl acetate accumulation in the cytoplasm	[90]
Strawberry (AAT)	Clostridium acetobutylicum	Butyl butyrate	40.60 mg/L	The one-step fermentation of butyl butyrate from glucose in the engineered C. acetobutylicum	[99]
Apple (AAT)			50.07 mg/L
S. cerevisiae (ATF1)	E. coli	2-Phenylethyl acetate	687 mg/L	An economical process for the biosynthesis of 2-PEAc directly from glucose	[111]
S. cerevisiae (ATF1)	S. cerevisiae	Isobutyl acetate	260.2 mg/L	Increase the ester production by improving the mitochondrial pyruvate concentration towards branched-chain alcohol biosynthesis	[112]
		3-Methyl-1-butyl acetate	296.1 mg/L
		2-Methyl-1-butyl acetate	289.6 mg/L
Rosa hybrida (AAT)	E. coli	Geranyl acetate	10.36 g/L	Biosynthesis of monoterpene esters	[113]
Strawberry (AAT)	E. coli	Butyl acetate	0.64 g/L	Engineer modular microbial platforms for anaerobic production of butyryl-CoA-derived designed esters from renewable feedstocks	[84]
		Butyl butyrate	0.45 g/L
		Ethyl butyrate	0.41 g/L
S. cerevisiae (ATF1)	E. coli	Anisyl acetate	355 mg/L	An efficient artificial biosynthetic pathway from glucose to anisyl acetate	[114]
S. cerevisiae(ATF1)	E. coli	Butyl acetate	22.8 g/L	Optimization of AAT expression and redox balance with auto-inducible fermentative controlled gene expression	[115]
Marinobacter hydrocarbonoclasticus (WS2)	S. cerevisiae	Fatty acid ethyl ester	5 g/L	Push–pull-block strategy	[116]
S. cerevisiae (ATF1)	E. coli	Isoprenyl acetate	28 g/L	Harnessing the IPP-bypass MVA pathway	[117]
Strawberry (AAT)	Clostridium tyrobutyricum	Butyl butyrate	62.59 g/L	Under mannitol with fed-batch fermentation in a 5 L bioreactor, which is the highest butyl butyrate titer reported so far	[118]