OPTIMIZATION OF HYDROGEN PRODUCTION FROM FRUIT WASTE THROUGH MESOPHILIC AND THERMOPHILIC DARK FERMENTATION: EFFECT OF SUBSTRATE-TO-INOCULUM RATIO

This research was aimed to optimize hydrogen production from fruit waste, particularly on the effect of the substrate-toinoculum ratio (SIR). Production of hydrogen was carried out through dark fermentation process both in mesophilic (30 °C, 1 atm) and thermophilic (55 °C, 1 atm) condition. Fermentation was conducted at SIR value ranging from 0.800 to 174 VSsubstrate/g VSinoc. In mesophilic fermentation, the highest cumulative total gas yield was achieved at SIR value of 19 corresponding total gas yield of 113 ml STP/g VS (5%v of H2). In thermophilic condition, the highest H2 yield was obtained at SIR value of 0.800 VSsubstrate/g VSinoc with H2 yield of 294 mL STP/g VS (50 – 60%v of purity). It was noticed that the lower SIR value, the higher hydrogen yield. In summary, it is concluded that substrate-to-inoculum ratio (SIR) plays important role in dark fermentation process to produce renewable energy of hydrogen fuel.