Optimasi Konsentrasi Arabinosa sebagai Ko-substrat untuk Produksi Xilitol oleh Sel Amobil Candida tropicalis

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.