Respiratory Quotient from Chemistry

A brief consideration of bacteriology introduces a simple calculation of the RQ-A variety of naicroorganisms can use long-chain alkanes (paraffin wax) or short-chain alkanes as an energy source (Van Eyk and Bartels, 1%8) The complete oxidation of alkanes has the. same outcome, whether catalyzed by a flame at a candlewick, a spark inside a furnace, or enzymes within a Jiving cell. Complete oxidation of hexane means that all of the carbon atoms arc oxidized to carbon dioxide  

For simplicity, the discharged hydn gen atoms and consumed oxygen molecules are not UTitten in Eq. (5,1), The discharged hydrogen atoms are shown in the next reaction. For convenience in working through the calculations, they may be written as 

The reducing equivalents released from aerobically consumed fuels are transferred to oxygen, producing water, Including water in the formula for hexane oxidation yields 

The final step is to add the correct number of oxygen molecules. The right-hand side of Eq, (5.3) shows 19 oxygen atoms. This means that there must be 19 oxygen atoms on the left-hand side. As the atmosphere contains Oj, rather than oxygen atoms, it is more appropriate to write the 19 oxygen atoms as 19/2 O2, or 9.5O3  

The RQ of hexane, as calculated from Equation (5.4), is CO2/O2 = 6/9.5 = 0.63. Hexane is an alkane. Fatty adds are quite similar in structure to alkanes. The RQ for the complete combustion of fatty adds has a value close to 0-6- 

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