Ethanol production by co-fermentation of molasses and oil palm empty fruit bunch hydrolysate

Maximum ethanol production by co-fermentation of molasses (22%, w/v total sugar) and oil palm empty fruit bunch (OPEFB) hydrolysate was 61.60 g/l (0.38 g/g sugar) at 72 h, while maximum ethanol produced from the molasses was 53.89 g/l (0.34 g/g sugar). OPEFB slurry (the OPEFB hydrolysate which contained solid residue of pretreated OPEFB) gave maximum ethanol 68.77 g/l (0.44 g/g sugar) when it was co-fermented with the molasses. After fermentation, scanning electron micrograph of pretreated OPEFB in the OPEFB slurry revealed yeast cells adsorped to the pretreated OPEFB. The results indicated that ethanol production by co-fermentation of molasses and OPEFB hydrolysate was cumulative sum of ethanol produced from each raw material, and pretreated OPEFB suspended in OPEFB hydrolysate increased ethanol production in the co-fermentation of molasses and OPEFB hydrolysate.