Depletion of the fossil fuels together with an increase in energy demand is considered as a serious threat to the world. Furthermore, fuel versus food dilemma plays an important role in search of sustainable non-edible feedstocks for production of biofuels. Liquid biofuels such as bioethanol can pave way for a cleaner earth together with less dependency on fossil fuels. Empty fruit bunches (EFBs) is one of the potential biomass wastes, which can be utilized as a raw material for bioethanol production. The high availability of EFBs as a biowaste in Malaysia can endorse the concept of waste-to-wealth that had been long dreamed since late 1990, where unwanted wastes are converted into valuable energy. The three important steps in bioethanol production from EFBs, i.e. pretreatment, hydrolysis, and fermentation are discussed in this paper. This review paper highlights some available literature and detailed information regarding the EFBs as a potential feedstock for bioethanol production in Malaysia. An environmentalfriendly bioenergy and zero waste can be anticipated in Malaysia which in turn promotes an economically sustainable bioethanol production. This review is vital as it explores the EFBs potential as a promising feedstock for bioethanol which can be implemented for future commercial purpose.

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A simultaneous saccharification and fermentation (SSF) optimization process was carried out on pretreated empty fruit bunches (EFBs) by employing the Response Surface Methodology (RSM). EFBs were treated using sequential acid-alkali pretreatment and analyzed physically by a scanning electron microscope (SEM). The findings revealed that the pretreatment had changed the morphology and the EFBs’ structure. Then, the optimum combination of enzymes and microbes for bioethanol production was screened. Results showed that the combination of S. cerevisiae and T. harzianum and enzymes (cellulase and β-glucosidase) produced the highest bioethanol concentration with 11.76 g/L and a bioethanol yield of 0.29 g/g EFB using 4% (w/v) treated EFBs at 30 °C for 72 h. Next, the central composite design (CCD) of RSM was employed to optimize the SSF parameters of fermentation time, temperature, pH, and inoculum concentration for higher yield. The analysis of optimization by CCD predicted that 9.72 g/L of bioethanol (0.46 g/g ethanol yield, 90.63% conversion efficiency) could be obtained at 72 h, 30 °C, pH 4.8, and 6.79% (v/v) of inoculum concentration using 2% (w/v) treated EFBs. Results showed that the fermentation process conducted using the optimized conditions produced 9.65 g/L of bioethanol, 0.46 g/g ethanol yield, and 89.56% conversion efficiency, which was in close proximity to the predicted CCD model.

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Biodiesel production from Waste Palm Cooking Oil (WPCO) is of interest to substitute fossil derived diesel fuel, due to its renewable nature, cleaner emissions and non-toxic properties. Thus, in this study, biodiesel production through transesterification process was optimized using immobilized lipase from Candida rugosa and WPCO collected from the faculty’s cafeteria as a feedstock. Interaction between five operating factors: molar ratio of ethanol to oil, water content, lipase loading, reaction temperature and time on the biodiesel yield were investigated. It was observed that, with the optimal conditions of 10:1 molar ratio of ethanol to oil, 1 g water, temperature 40 °C, 0.8 g immobilized lipase and 32 h reaction time, a yield of 85.72% of biodiesel could be achieved. Thus, this study shows that WPCO, an environmental waste, can be utilized as a promising feedstock for biodiesel production using environmentally friendly biocatalysts such as immobilized lipase.