Thermochemical Buswell's Equation for Biohydrogen: Counting Heat of Dark Fermentation

Dark fermentation is an anaerobic microbial-mediated redox system represented by Buswell's equation for biohydrogen, in which thermal parameters such as theoretical higher heating value and energy conversion efficiency are applied to evaluate the degradability performance of organic matter, but the standard heat of Buswell's equation for biohydrogen has not been established. Likewise, the standard heat of biohydrolysis and standard heat of bioredox, two sub-reactions of dark fermentation, have not yet been established. This study uses the stoichiometric Buswell's equation for biohydrogen as an energy model to quantify the standard heat of Buswell's equation for biohydrogen, the standard heat of biohydrolysis, and the standard heat of bioredox. Through the integration of the theoretical higher heating value of organic matter and mathematical thermal mathematical equation of Buswell’s equation for biohydrogen, this study concludes that (i) the standard heat of Buswell's equation for biohydrogen is demonstrated as an endothermic reaction, (ii) the standard heat of Buswell's equation for biohydrogen is identified as the sum of the standard heat of biohydrolysis and the standard heat of bioredox, (iii) the standard heat of bioredox can be calculated using the theoretical higher heating value of organic matter via the derived mathematical equation, and (iv) the standard heat of biohydrolysis can be determined by the difference between the standard heat of Buswell's equation for biohydrogen and the standard heat of bioredox.