Tuesday, April 30, 2013
Exhibit Hall
Oil palm empty fruit bunch (EFB) is a major solid waste resulting from the palm oil milling process. Its richness in hemicellulose content has contributed to the potential use of EFB for xylitol production. Xylitol is a high value-added five-carbon polyol sweetener with several health benefits. Biological production of xylitol from EFB is more attractive as compared to current industrial production of xylitol using nickel-dependent chemical reduction of pure xylose, because it is cost-effective and environmental-friendly. The lack of comprehensive optimized operating conditions, however, has led to unsatisfactory xylitol recovery. The objective of this study is to optimize, using response surface methodology, xylitol production from EFB by Candida tropicalis IMR C480/08A. The production of xylitol was achieved using a 24 hour batch fermentation at 30°C. The effect of operating conditions, namely initial pH, initial xylose concentration, initial cell concentration and agitation speed, were investigated. The optimum initial pH, initial cell concentration, initial xylose concentration and agitation speed were pH 4.86, 2.0 gL-1, 156.47 gL-1 and 250 rpm, respectively. Under these optimal conditions, a maximum xylitol yield of 12.74 gL-1 was produced with a bioconversion yield of 1.08 gg-1 and a volumetric rate of xylitol generation of 0.57 gL-1h-1. The xylose-to-xylitol bioconversion yield in this study was greatly enhanced as compared to the existing report on xylitol production from EFB, with a reported bioconversion yield of 0.51 gg-1. The optimized batch fermentation conditions from this study may be used as constructive guidelines for the industrial scale-up of xylitol production from EFB.