| dc.description.abstract | This research was carried out to investigate xylitol production by Candida tropicalis immobilized cells under two sets condition, which were addition of arabinose as a co-substrate and its fermented on sugar mixed medium. Ratio xylose to arabinose was used at the range 6:1-6:3% (xylose 30 g/L and arabinose 5-15 g/L). Sugar mixed medium variation which used in this research were xylose and glucose; xylose and arabinose; and also xylose, glucose, and arabinose, respectively. Candida tropicalis cells entrapped in Ca-alginate and incubated in batch fermentation on 100 rpm rotary shaker at 30˚C for 96 hours. Xylitol produced by cells were measured using spectrophotometer and by D-sorbitol/Dxylitol enzymatic assays. The results revealed that addition of arabinose at the range 6:1-6:3% could increased xylitol production (3.11-5.90 g/L). The highest volumetric rate of xylitol production (0.06 g/L h) and yield product (0.20 g xylitol produced /g xylose consumed) were achieved at ratio 6:3%. Contrary with glucose in fermentation medium could decreased xylitol production of 20% compared with control medium. This negative effect of glucose was annulled by adding arabinose in sugar mixed medium containing xylose, glucose, and arabinose can reached xylitol production for 4.2 g/L. | en |
