Unlocking the potential of peach pulp residue for the simultaneous production of biohydrogen and biobutanol using Clostridium pasteurianum and Clostridium tyrobutyricum

This paper presents the potential valorization of peach pulp residue (PPR) for simultaneous fermentative hydrogen and butanol production. Two different Clostridium strains - Clostridium pasteurianum (CP) and Clostridium tyrobutyricum (CT) - are employed for the dark fermentation, with daily measurements of gas production and fermentation metabolites. The volumetric hydrogen production rates are 2564.60 mL/L·day for CP and 2270.40 mL/L·day for CT. The hydrogen yields are 2.25 mol/mol glucose for CP and 2.10 mol/mol glucose for CT. CP exhibits a higher acetic acid yield (1.93 mol), whereas CT demonstrates higher yields of butyric acid (0.59 mol), butanol (0.21 mol), and ethanol (0.31 mol) per mol of glucose. The carbon flow analysis indicates that both CP and CT follow the principle of liquid-phase product balance. These findings underscore the potential for bioconversion of PPR into biohydrogen, organic acids, butanol, and ethanol, thereby contributing to waste valorization and the production of affordable and clean energy.