title: Statistical approach to study the interactive effects of process parameters for enhanced xylitol production by Candida tropicalis and its potential for the synthesis of xylitol monoesters.
abstract: Previous results showed that an indigenously isolated yeast strain of Candida tropicalis was found to produce 12.11 g/L of xylitol under unoptimized conditions in presence of 50 g/L of xylose. In the present study, optimizing the process using one-variable at-a-time resulted in the production of 59.07 g/L of xylitol in 96 h in presence of 100 g/L xylose. Further optimization using response surface methodology led to the production of 65.45 g/L in medium containing 100 g/L xylose, 0.5% yeast extract, 0.03% MgSO(4).7H(2)O and 0.2% KH(2)PO(4), pH-4.5, 30 °C, 200 r/min for 96  h with 4% inoculum level. Addition of 1% methanol in response surface methodology optimized-medium led to the production of 67.12 g/L. Scaling up in 10 L fermentor resulted in productivity of 0.80 g/Lh with yield of 0.68 g/g. Efficient synthesis of xylitol esters was achieved with butyric acid (50.32%) and caproic acid (38.36%) in 4 h using Pseudomonas aeruginosa lipase in t-butanol: tetrahydrofuran (1:1 v/v).
authors.affiliation: Department of Microbiology University of Delhi South Campus, New Delhi, India.
authors.forename: Swati
authors.initials: S
authors.lastname: Misra
authors.forename: Shailendra
authors.initials: S
authors.lastname: Raghuwanshi
authors.forename: Rajendra Kumar
authors.initials: RK
authors.lastname: Saxena
mesh_terms: D000704:Analysis of Variance; D020148:Butyric Acid / Q000378:metabolism; D041022:Candida tropicalis / Q000378:metabolism*; D002208:Caproates / Q000378:metabolism; D004952:Esters / Q000378:metabolism; D005285:Fermentation; D008049:Lipase / Q000378:metabolism; D000432:Methanol; D011550:Pseudomonas aeruginosa / Q000201:enzymology; D014993:Xylitol / Q000096:biosynthesis*; D014994:Xylose / Q000378:metabolism
chemical_list: D002208:Caproates; D004952:Esters; D020148:Butyric Acid; C037652:hexanoic acid; D014994:Xylose; D008049:Lipase; D014993:Xylitol; D000432:Methanol
keywords: Candida tropicalis; Xylitol; ester synthesis; process optimization; response surface methodology