Kinetic of xylitol fermentation by candida grown under batch cultivation

MONASTERIO, R.P.; PATTACINI, S.; PASTOR, M.D.

Rosario

Congreso; V Congreso Argentino de Microbiología General; 2008

Sociedad Argentina de Microbiología General

Xylitol is an economically important product used in the pharmaceutical, chemical and food industries owing to the dietetic and anticariogenic properties. Traditionally, xylitol has been produced almost exclusively by chemical process, which involves an expensive step of purifications of xylose. In recent years, attention has been focused on the biotechnological process, because it does not require initial xylose purification and is conducted under moderate temperature and atmospheric pressure. In the present work, we report the kinetic results of xylitol fermentation by Candida grown under batch cultivation. Optimal conditions for xylitol production, including pH value, medium composition and inoculation parameters. Debaryomyces hansenii NRRL Y-7426, Candida parapsilosis NRRL Y-12969, Candida guilliermondii NRRL Y-2075, Candida boidinii NRRL Y-2332, Candida tropicalis NRRL Y-12968 were used in the fermentation experiments. The inoculums were prepared from a suspension of cells in shaken flask assay. Cell concentration was determined by drying washed biomass at 105 ºC to constant weight and number of cells/mL in the Neubauer camera in microscopy and pH evolution. Xylosa and xylitol concentrations were determined by high-performance liquid chromatography (HPLC) using column LiChrosarb-NH2, 5µm, 200 x 46 mm, detector IR. And xylosa was determined by DNS (reductor sugars) in spectrophometer. Five strains were used in assays, were determinate fast growth. The high values of dry weight in g/L and cells/ml were valuated in C. guilliermondii (20,09; 5,07 x 109), C. tropicalis (6,27; 1,91 x 109