Considering the following chemical equation, guess what could be the nature of respiratory substrate?
$2\,\mathrm{C}_{51}\mathrm{H}_{98}\mathrm{O}_{6} + 145\,\mathrm{O}_{2} \rightarrow 102\,\mathrm{CO}_{2} + 98\,\mathrm{H}_{2}\mathrm{O} + \text{Energy}$