Influence of storage conditions on oil palm frond juice as a renewable feedstock for bioethanol production

Abstract

The high fermentable sugars content in oil palm frond (OPF) juice makes it an excellent fermentation feedstock for bioethanol production. The major challenge of using the juice as a feedstock is the rapid degradation of the fermentable sugars during storage. Thus, this study was aimed to investigate the effects of OPF juice concentration and mild temperature storage on its glucose content. The OPF juice was obtained by pressing the fresh OPF petiole and it was concentrated by evaporating 30–70% (v/v) of water from the juice. The juice was stored at different temperatures (30–60 °C) for 20 days prior to its use for bioethanol production. The results showed that regardless of the OPF juice concentration, the glucose content remained stable at 50 °C and 60 °C storage. Moreover, bacterial spoilage in the OPF juice was slightly inhibited when stored at 50 °C and it completely disappeared when stored at 60 °C. The production of bioethanol using OPF juice stored at 50 °C gave approximately 15% higher bioethanol production when compared to the use of freshly prepared OPF juice. The results indicate that 50% concentrated OPF juice stored at 50 °C are promising alternative pre-treatment and storage conditions for OPF juice liquid feedstock prior to its use for bioethanol fermentation.