Environmental performance of bioethanol production from oil palm frond petiole sugars in an integrated palm biomass biorefinery

Abstract

Generation of biofuels from renewable resources such as lignocellulosic biomass is a promising approach to reduce the sole reliability on the depleting fossil fuel. The aim of this work is to assess the potential environmental impact of bioethanol production from oil palm frond in a conceptual oil palm based biorefinery model, utilizing wet disc milling as a pretreatment method. A cradle-to-gate approach was selected, beginning with the harvesting and transportation of the frond petiole from the plantation, followed by production of oil palm frond petiole sugars via pretreatment and saccharification prior to bioethanol fermentation, and finally purification of the fermentation products to obtain anhydrous bioethanol. A life cycle assessment was performed using CML 2 baseline 2000 method (SimaPro v8.0), where ten impact categories were evaluated. It was found that the most significant environmental impact was from sugar recovery process with contribution of more than 90 %. This is mainly due to high power consumption by wet disc milling during pretreatment. Apart from that, production of enzyme and chemicals which were used during saccharification consumes high energy thus contributing major problems to the surrounding. Finding of this study helps to identify the hotspot which can be improved to establish a more energy efficient and greener system for bioethanol production from oil palm frond petiole sugars.