Palm kernel cake (PKC) was used for biobutanol production by Clostridium saccharoperbutylacetonicum N1-4 in acetone-butanol-ethanol (ABE) fermentation. PKC was subjected to acid hydrolysis pretreatment and hydrolysates released were detoxified by XAD-4 resin. The effect of pH, temperature and inoculum size on butanol production was evaluated using an empirical model. Twenty ABE fermentations were run according to an experimental design. Experimental results revealed that XAD-4 resin removed 50% furfural and 77.42% hydroxymethyl furfural. The analysis of the empirical model showed that linear effect of inoculums size with quadratic effect of pH and inoculum size influenced butanol production at 99% probability level (P < 0.01). The optimum conditions for butanol production were pH 6.28, temperature of 28 degrees C and inoculum size of 15.9%. ABE fermentation was carried out under optimum conditions which 0.1 g/L butanol was obtained. Butanol production was enhanced by diluting PKC hydrolysate up to 70% in which 3.59 g/L butanol was produced. (C) 2014 Elsevier Ltd. All rights reserved.