268218 Purification of Arabitol From Fermentation Broth of Debaryomyces Hansenii Using Glycerol As Substrate
Arabitol, a five carbon sugar alcohol, has many potential industrial applications. This work deals with the recovery of arabitol from fermentation broth containing arabitol, unconsumed glycerol and other minor impurities. Arabitol was produced by fermentation of Debaryomyces hansenii in a suitable medium containing glycerol as the carbon source. To collect and purify arabitol from the broths, studies were done and the following process developed. The supernatant was first treated with 8 g/l of activated carbon for decoloration and removal of some impurities. Then glycerol was removed by acetone extraction. To obtain the necessary phase equilibrium information, solubility and liquid-liquid equilibrium studies were done with simulative three-component acetone-glycerol-xylitol systems. Xylitol, an enantiomer of arabitol, was used because it was much less expensive and more readily available than pure arabitol. Selective extraction of glycerol by acetone from the broth was accordingly designed and optimized. The extraction remainder, containing the desirable arabitol, was dried to remove the residual acetone and then extracted for arabitol with hot butanol (900 ml per liter of supernatant at 90°C).White arabitol crystals were collected from the extract cooled to room temperature. The overall recovery and purity of arabitol crystals were 66% and 95%, respectively. Arabitol loss occurred primarily during the acetone extraction to remove glycerol. Lowering the unconsumed glycerol concentration in fermentation broth is critically important to the overall arabitol production cost.
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