Question

One strategy for converting biomass to conventional hydrocarbon fuels involves the use of naturally occurring bacterial enzymes. In certain cyanobacteria, a fatty acyl-ACP undergoes conversion to a fatty aldehyde. An aldehyde decarbonylase acts on the aldehyde, producing CO and an alkane. Identify the alkanes generated from stearoyl-ACP and palmitoyl-ACP.

Short answer

The alkanes Heptadecane and pentadecane are generated from stearoyl-ACP and palmitoyl-ACP.

Step-by-step solution

Definition of ACP

The acyl carrier protein (ACP) is a cofactor in the production of fatty acids. During production and oxidation, ACP works as a fatty acid chain transporter.

It accomplishes this by facilitating fatty acid acyl chain transfer from mitochondria to cytosol.

Reactions for alkane synthesis

The reactions for alkane synthesis via the conversion of acyl-ACP to aldehyde and the decarbonylase reaction are as follows:

The fatty acyl of stearic acid ${\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{16}\mathrm{COOH}$is converted to fatty aldehyde by the following reaction:

${\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{16}\mathrm{COO}-\mathrm{SACP}\to {\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{16}\mathrm{CHO}$

Aldehyde decarbonylase reaction:

${\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{16}\mathrm{CHO}\to \mathrm{CO}+{\mathrm{C}}_{17}{\mathrm{H}}_{36}$

The fatty acyl of palmitic acid ${\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{14}\mathrm{COOH}$is converted to fatty aldehyde by the following reaction:

${\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{14}\mathrm{COO}-\mathrm{SACP}\to {\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{14}\mathrm{CHO}$

Aldehyde decarbonylase reaction:

$$\begin{gathered} {\mathrm{CH}}_3{\left({\mathrm{CH}}_2\right)}_{14}\mathrm{CHO}\to \mathrm{CO}+{\mathrm{C}}_{15}{\mathrm{H}}_{32} \\ **{\mathrm{C}}_{15}{\mathrm{H}}_{32}‐\mathrm{pentadecane} \end{gathered}$$

The alkanes generated from stearoyl-ACP and palmitoyl-ACP are Heptadecane and pentadecane.