Utilization of Glucose Recovered by Phase Separation System from Acid-hydrolysed Oil Palm Empty Fruit Bunch for Bioethanol Production

Oil palm empty fruit bunch (OPEFB) is one the most abundant lignocellulosic wastes produced throughout the year in the palm oil industry. A new process of separating lignocellulose components after acid hydrolysis (known as phase separation system) has been previously developed, by which lignin and carbohydrate can be completely and rapidly separated in 60 minutes between 25 and 30°C. In this process, cellulose is completely hydrolyzed to oligosaccharides and remains in the acid phase. The maximum glucose yield of 53.8% was obtained by hydrolysis, with 4% acid after autoclaving at 121°C for 5 minutes. This work focused on the separation of monosaccharide (glucose) from cellulose fraction, which was subsequently used as a substrate for ethanol production. For this purpose, different types of nitrogen sources were evaluated, with yeast extract as the best nitrogen source (93% of theoretical yield) as compared to palm oil mill effluent (POME) and sludge powder for the growth of acid tolerant Saccharomyces cerevisiae ATCC 26602. Batch and repeated batch fermentation of S. cerevisiae ATCC 26602 using OPEFB hydrolysate gave 0.46 g glucose g ethanol-1, representing 87% of theoretical yield with a productivity of about 0.82 g-1 l-1 h-1 and 0.48 g glucose g ethanol- 1,representing 89% of theoretical yield with productivity of about 2.79 g-1 l-1 h-1, respectively