Biohydrogen production through separate hydrolysis and fermentation and simultaneous saccharification and fermentation of empty fruit bunch of palm oil

Indonesia produces 32 million tons of palm oil per year, the largest volume of yearly palm oil production. This massive amount of palm oil production has led to the accumulation of a large amount of empty fruit bunch (EFB) disposed as solid waste. EFB acts as a lignocellulosic biomass consisting of 43 % cellulose, 23% hemicellulose and 33% lignin. EFB can potentially be utilized as a raw material to produce biohydrogen, one of the various bio-energy forms. The EFB was initially subjected to delignification using Aspergillus fumigatus for seven days at 30°C in the pH range of 5-6. This biodelignification is intended to increase the accessibility of cellulase towards the EFB biomass before being converted into biohydrogen by Enterobacter aerogenes. In this work, the delignified EFB was subjected to produce biohydrogen through SHF and SSF methods. The results demonstrate that the production of biohydrogen using EFB as raw material through the SHF method has many weaknesses. The main disadvantage was the product of reducing sugar (RS) inhibits cellulase activity. Cellulase was found to be inactive and sugar production stopped during the fermentation process. Furthermore, E. aerogenes underwent material insufficiency to be converted to hydrogen. The maximum product of biohydrogen was 15.5 ml/g EFB on 260 g EFB/L, with the cellulase concentration of 36 FPU/g EFB. Biohydrogen production using E. aerogenes was significantly affected by the cellulase concentration and the amount of EFB. The production of biohydrogen increased significantly using the SSF method. The highest production of hydrogen gas was 635.3 ml which was achieved at the EFB weight of 220 g/L with a cellulase concentration of 36 FPU/g EFB. The effectiveness of the SSF method for biohydrogen production is shown by the reduction of cellulose (28.70%) and hemicellulose (23.53%), compared to the SHF method.