TABLE 7.

Pathway selectivity and productivity^a

Pathway variant	Enzyme ratios	Selectivity (n-butanol/ethanol ratio)b		Specific productivity (mol of C/h/g of enzyme) (predicted)c
		Measured	Predicted	n-Butanol	Ethanol	Overall
X514-Bad/X514-Bdh	Equal activity	0.41 ± 0.02	0.14 ± 0.06	35	95	112
	Optimized	2.59 ± 0.02	1.80 ± 0.11	53	12	45
X514-AdhE	Equal activity	0.05 ± 0.01	0.02 ± 0.01	9.4	99	102
	Optimized	1.31 ± 0.01	1.82 ± 0.06	21	2.8	13
Cbei-Bad/Cacet-Bdh	Equal activity		0.19	12	2.1	2.7
	Optimized		2.88	29	0.4	3.2

^aFor reactions run at 60°C, 5-min reaction time scale.

^bMoles of carbon in the n-butanol/ethanol ratio.

^cAverage rate to produce 90% of the final alcohol concentration.