Table 5.

Summary of efflux pumps applied in tolerance engineering.

Microbes	Stressors	Methods	Refs
E. coli	limonene	A library of efflux pumps was constructed and a best efflux pumps to enhance tolerance to limonene was obtained by screening in the library.	[80]
E. coli	isopentenol	Genes up-regulated response to isopentenol was identified.	[81]
E. coli	1-hexene, 1-octene, and 1-nonene	Directed evolution of AcrB	[82]
E. coli	n-octane and α-pinene	Directed evolution of AcrB	[83]
E. coli	n-butanol	Directed evolution of AcrB	[84]
E. coli	n-butanol	The expression of efflux pumps was regulated by stress promoter.	[85]
S. cerevisiae	stressors from lignocellulosic ethanol fermentation	The tolerance genes was dynamically regulated by stress-driven promoters.	[114]