To convert oil palm biomass to liquid biofuels, several technologies in the pipeline that can be considered are pyrolysis (bio-oil), catalytic depolymerisation (synthetic diesel), microbial fermentation (bioethanol) and hydrotreating (hydrocarbon fuel). In all endeavour, the most important stage is oil palm biomass pretreatment as it has been well documented as one of the most tedious and energy intensive processes due to difficulty in breaking the complicated cell wall of oil palm biomass.

Pyrolysis of oil palm biomass generates bio-oils and other coproducts such as biochar and gas in different concentration at varying temperature ranges. MPOB has set up a pyrolysis experimental rig for small-scale slow pyrolysis (Sukiran et al. 2010,2011) and a Biomass Experimental Kit (BEK) for larger scale biochar produc­tion as the targeted product. The biochar produced has potential for soil remedy and GHG emissions reduction (carbon sequestration). Other emerging pyrolysis tech­nology is microwave-induced pyrolysis (Salema and Ani 2011; Omar et al. 2011).

Under the National Key Economic Area (NKEA), one attempt is to set up com­mercial pyrolysis plant to produce bio-oil from EFB. The bio-oil produced will be used to replace fossil-based fuels.

The bioethanol production from EFB involves three processes, i. e. thermo — mechanical/chemical fractionation, sugar hydrolysis and extraction followed by microbial fermentation (Malaysia-Danish Environmental Cooperation Programme 2008; Politov et al. 2009; Mohd Asyraf et al. 2011a, b; Ria et al. 2011). The poten­tial bioethanol production is about 388 L of ethanol per tonne of EFB (Malaysia — Danish Environmental Cooperation Programme 2008). Two forms of oil palm biomass, i. e. EFB and oil palm trunk (OPT), can be used in fermentation to produce bioethanol (Yamada et al. 2010). The biomass samples must be subjected to a pre­treatment via delignification with 1% NaOH, acid hydrolysis and enzymatic sac­charification prior to fermentation process and then fermented using Saccharomyces cerevisiae to produce fermentation broth which yields a mixture of bioethanol and water coproducts after distillation.

Although there is an active pursuit on pilot and commercial scale production of bioethanol from oil palm biomass, the bioethanol plant is far from reaching on the ground. However, with the penetration of more promising technologies, there is plan to set up pilot and commercial biorefinery plant side by side at palm oil mills to produce various products from oil palm biomass (The Star 2011).

With the current market trends and demand towards sustainable development and climate change mitigation, it is envisaged that the future trend in bioenergy deployment is probably to convert oil palm biomass into aviation fuel. Research has shown that a few palm esters can be used as potential aviation fuel. Besides, a trial is ongoing to produce aviation fuel via hydrotreating process (MPOB in collabora­tion with UOP).