Engineering nature for gaseous hydrocarbon production

Table 2 Relative In vitro and In vivo studies of ADO and CvFAP for the production of alkane gases

Alkane production (relative k_app min⁻¹)
Enzyme variant	Propane	Butane	Refs.
ADO kinetic studies relative to wild-type^a
A134F	4.5	5.9	[32]
V41Y	1.0	1.8	[32]
A134F/V41Y	1.0	1.3	[32]
A118L	2.2	nd	[38]
A118F	2.2	nd	[38]
A121F	3.3	nd	[38]

Substrate	Decoy	Alkane	Alkane (μM)	Refs.
CvFAP wild-type kinetic studies^b
Formic acid	None/C15	H₂	48.8/291.7	[36]
Acetic acid	None/C14	methane	2.7/7.5	[36]
Propionic acid	None/C13	ethane	103/347.1	[36]
Butyric acid	None/C12	propane	382.2/1090.5	[36]
Isobutyric acid	None/C13	propane	305.2/1007	[36]
Valeric acid	None/C9	butane	860.7/2440	[36]
Isovaleric acid	None/C9	isobutane	268.6/940.2	[36]

Alkane production (mg/L)
Enzyme variant	Propane		Butane	Isobutane	Refs.
ADO In vivo production of alkane gases^c
Wild-type	0.27		nd	nd	[32]
A134F	0.46		nd	nd	[32]
CvFAP In vivo production of alkane gases in E. coli^d
Wild-type	7.0		17.7	5.6	[6]
G462A	17.6		33.5	30.2	[6]
G462F	31.2		27.7	28.6	[6]
G462I	43.8		47.1	86.8	[6]
G462V	24.5		21.9	17.4	[6]
CvFAP In vivo production of alkane gases in other microorganisms^e
G462I in Halomonas TQ10		7.0	17.7	5.6	[6]
G462I in Synechocystis		17.6	33.5	30.2	[6]

nd not determined
^aKinetic studies of isolated enzymes in the presence of butyraldehyde or valeraldehyde using a chemical reducing system (ferrous ammonium sulphate, phenazine methosulphate and NADH). Data is expressed as relative k_app (min⁻¹) compared to wild-type enzyme
^bKinetic studies of CvFAP isolated enzymes with 150 mM substrate ± a decoy molecule
^cIn vivo production of propane with ADO co-expressed with ferredoxin in E. coli. Cultures were grown in the presence of 10 mM butyraldehyde
^dE. coli cultures expressing CvFAP in the presence of supplemental 10 mM butyric, valeric or isovaleric acid
^eCultures expressing CvFAP_G462I in the presence of 80 mM butyrate or CO₂ for Halomonas or Synechocystis, respectively

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