The efficiency of cell growth in a substrate in a biotechnology process was given in a rep...

The efficiency of cell growth in a substrate in a biotechnology process was given in a report as

In the notation table

η is the energetic efficiency of cell metabolism (energy/energy)

 is the cell yield, carbon basis (cells produced/substrate consumed)

γb is the degree of reductance of biomass (available electron equivalents/g mole carbon, such as 4.24 e- equiv./mol cell carbon)

is the biomass heat of combustion (energy/available electron equiv.)

ΔHcat is the available energy from catabolism (energy/mole substrate carbon)

Is there a missing conversion factor? If so, what would it be? The author claims that the units in the numerator of the equation are (mol cell carbon/ mol substrate carbon) (mol available e-/mol cell carbon) (heat of combustion/ mol available e-). Is this correct?