Sustainable hydrogen production from fruit and vegetable waste (FVW) using mixed anaerobic cultures via dark fermentation: kinetic aspects

Abstract

The study explores the effects of different pH ranges (5.5–8) and food to microorganism (F/M) ratios (0.5–2) on the H2 production from fruit and vegetable waste (FVW). The study was performed via dark fermentation of mixed FVW without temperature control. The study highlights the effect of different kinetic parameters, such as lag time (λ), maximum H2 production rate (Rmax), and H2 production potential (Pmax) along with the correlation coefficient (R2). The finding shows that H2 production was limited to the first 72 h of fermentation. Furthermore, the pH in the range of 7–7.5 was observed to be suitable for H2 production via dark fermentation. The highest accumulated H2 yield of 125 ml was observed at pH 7.5. The F/M ration has a significant effect on the H2 yield. The H2 yield increased with an increase in the concentration of the substrate. Moreover, the H2 yield was highest for the F/M ratio of 1:1 and decreased when the ratio was 2:1. A modified Gompertz equation adequately (i.e., R2 > 0.99) describes the cumulative H2 yield. The present work highlights a sustainable approach for the valorization of FVW. The sustainable H2 production using mixed anaerobic cultures via dark fermentation is feasible using FVW.