Xylitol microbial production

TABLE 18.1 Kinetic Parameters for Microbial Production of Xylitol by Candida Species... 

Onishi, H., Suzuki, T., 1969. Microbial production of xylitol from glucose. Applied Microbiology 18 (6), 1031-1035. 

Like D-glucose and D-fructose, however, D-xylose can be utilized chemic ly or microbially—to generate a variety of interesting five-ca n c emica s o er than furfural (vide supra) or xylitol, a noncaloric sweetener, both being duectly produced from xylan hydrolysates, that is, without the actual isolation of the sugar. Other readily accessible intermediate products of high preparative utiUty (Scheme 2.14) are the open-chain fixed dithioacetal, the D-xylal, and D-hydroxy-xylal esters, or pyrazol or imidazol A -heterocycles with a hydrophilic trihydroxypropyl side chain. 

The xylose produced via enzymatic hydrolysis of the hemicellulose fraction could be converted via microbial fermentation into xylitol (which has been listed by the US Department of Energy among the top 12 value-added platform chemicals) for the production of a range of chemicals, including xylaric acid, propylene glycol, ethylene glycol and a mixture of hydroxyl-furans and polyesters (Werpy and Petersen, 2004). 

D. hansenii (180). The highest xylitol concentration attained in microbial processes using xylose as substrate have been in the range of 200 to 220 g/L (181 184). Nakano et al. (185) reported very high xylitol (356 g/L) production by C. magnoliae in fed-batch culture under a microaerobic condition maintained by... 

Xylose is the main carbohydrate present in the hemicellulose fraction (second most abundant component of lignocellulose, representing about 80 % of total sugars) (Girio et al. 2010). Potentially, the released carbohydrates, mono- and dimeric sugars, are substrates for the production of value-added products such as ethanol, xylitol, n-butanol, 2,3-butanediol, and lactic acid via microbial fermentation processes (Chandel et al. 2010, 2011, 2012). 

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